This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake.

When curl is asked to pass along the hostname to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that hostname can be is 255 bytes.

If the hostname is detected to be longer than 255 bytes, curl switches to local name resolving and instead passes on the resolved address only to the proxy. Due to a bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long hostname to the target buffer instead of copying just the resolved address there.

This flaw allows an attacker to insert cookies at will into a running program using libcurl, if the specific series of conditions are met.

libcurl performs transfers. In its API, an application creates "easy handles" that are the individual handles for single transfers.

libcurl provides a function call that duplicates en easy handle called curl_easy_duphandle.

If a transfer has cookies enabled when the handle is duplicated, the cookie-enable state is also cloned - but without cloning the actual cookies. If the source handle did not read any cookies from a specific file on disk, the cloned version of the handle would instead store the file name as none (using the four ASCII letters, no quotes).

Subsequent use of the cloned handle that does not explicitly set a source to load cookies from would then inadvertently load cookies from a file named none - if such a file exists and is readable in the current directory of the program using libcurl. And if using the correct file format of course.

nscd: Stack-based buffer overflow in netgroup cache

If the Name Service Cache Daemon's (nscd) fixed size cache is exhausted by client requests then a subsequent client request for netgroup data may result in a stack-based buffer overflow. This flaw was introduced in glibc 2.15 when the cache was added to nscd.

This vulnerability is only present in the nscd binary.

nscd: Null pointer crashes after notfound response

If the Name Service Cache Daemon's (nscd) cache fails to add a not-found netgroup response to the cache, the client request can result in a null pointer dereference. This flaw was introduced in glibc 2.15 when the cache was added to nscd.

This vulnerability is only present in the nscd binary.

nscd: netgroup cache may terminate daemon on memory allocation failure

The Name Service Cache Daemon's (nscd) netgroup cache uses xmalloc or xrealloc and these functions may terminate the process due to a memory allocation failure resulting in a denial of service to the clients. The flaw was introduced in glibc 2.15 when the cache was added to nscd.

This vulnerability is only present in the nscd binary.

nscd: netgroup cache assumes NSS callback uses in-buffer strings

The Name Service Cache Daemon's (nscd) netgroup cache can corrupt memory when the NSS callback does not store all strings in the provided buffer. The flaw was introduced in glibc 2.15 when the cache was added to nscd.

This vulnerability is only present in the nscd binary.

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: Add rough attr alloc_size check

In the Linux kernel, the following vulnerability has been resolved:

fs: relax assertions on failure to encode file handles

Encoding file handles is usually performed by a filesystem >encode_fh() method that may fail for various reasons.

The legacy users of exportfs_encode_fh(), namely, nfsd and name_to_handle_at(2) syscall are ready to cope with the possibility of failure to encode a file handle.

There are a few other users of exportfs_encode_{fh,fid}() that currently have a WARN_ON() assertion when ->encode_fh() fails. Relax those assertions because they are wrong.

The second linked bug report states commit 16aac5ad1fa9 ("ovl: support encoding non-decodable file handles") in v6.6 as the regressing commit, but this is not accurate.

The aforementioned commit only increases the chances of the assertion and allows triggering the assertion with the reproducer using overlayfs, inotify and drop_caches.

Triggering this assertion was always possible with other filesystems and other reasons of ->encode_fh() failures and more particularly, it was also possible with the exact same reproducer using overlayfs that is mounted with options index=on,nfs_export=on also on kernels < v6.6. Therefore, I am not listing the aforementioned commit as a Fixes commit.

Backport hint: this patch will have a trivial conflict applying to v6.6.y, and other trivial conflicts applying to stable kernels < v6.6.

A vulnerability was found in systemd-coredump. This flaw allows an attacker to force a SUID process to crash and replace it with a non-SUID binary to access the original's privileged process coredump, allowing the attacker to read sensitive data, such as /etc/shadow content, loaded by the original process.

A SUID binary or process has a special type of permission, which allows the process to run with the file owner's permissions, regardless of the user executing the binary. This allows the process to access more restricted data than unprivileged users or processes would be able to. An attacker can leverage this flaw by forcing a SUID process to crash and force the Linux kernel to recycle the process PID before systemd-coredump can analyze the /proc/pid/auxv file. If the attacker wins the race condition, they gain access to the original's SUID process coredump file. They can read sensitive content loaded into memory by the original binary, affecting data confidentiality.

Issue summary: An application using the OpenSSL HTTP client API functions may trigger an out-of-bounds read if the 'no_proxy' environment variable is set and the host portion of the authority component of the HTTP URL is an IPv6 address.

Impact summary: An out-of-bounds read can trigger a crash which leads to Denial of Service for an application.

The OpenSSL HTTP client API functions can be used directly by applications but they are also used by the OCSP client functions and CMP (Certificate Management Protocol) client implementation in OpenSSL. However the URLs used by these implementations are unlikely to be controlled by an attacker.

In this vulnerable code the out of bounds read can only trigger a crash. Furthermore the vulnerability requires an attacker-controlled URL to be passed from an application to the OpenSSL function and the user has to have a 'no_proxy' environment variable set. For the aforementioned reasons the issue was assessed as Low severity.

The vulnerable code was introduced in the following patch releases: 3.0.16, 3.1.8, 3.2.4, 3.3.3, 3.4.0 and 3.5.0.

The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this issue, as the HTTP client implementation is outside the OpenSSL FIPS module boundary.

In the Linux kernel, the following vulnerability has been resolved:

blk-cgroup: Fix class @block_class's subsystem refcount leakage

blkcg_fill_root_iostats() iterates over @block_class's devices by class_dev_iter_(init|next)(), but does not end iterating with class_dev_iter_exit(), so causes the class's subsystem refcount leakage.

Fix by ending the iterating with class_dev_iter_exit().

In the Linux kernel, the following vulnerability has been resolved:

nfp: bpf: Add check for nfp_app_ctrl_msg_alloc()

Add check for the return value of nfp_app_ctrl_msg_alloc() in nfp_bpf_cmsg_alloc() to prevent null pointer dereference.

In the Linux kernel, the following vulnerability has been resolved:

tcp: drop secpath at the same time as we currently drop dst

Xiumei reported hitting the WARN in xfrm6_tunnel_net_exit while running tests that boil down to: - create a pair of netns - run a basic TCP test over ipcomp6 - delete the pair of netns

The xfrm_state found on spi_byaddr was not deleted at the time we delete the netns, because we still have a reference on it. This lingering reference comes from a secpath (which holds a ref on the xfrm_state), which is still attached to an skb. This skb is not leaked, it ends up on sk_receive_queue and then gets defer-free'd by skb_attempt_defer_free.

The problem happens when we defer freeing an skb (push it on one CPU's defer_list), and don't flush that list before the netns is deleted. In that case, we still have a reference on the xfrm_state that we don't expect at this point.

We already drop the skb's dst in the TCP receive path when it's no longer needed, so let's also drop the secpath. At this point, tcp_filter has already called into the LSM hooks that may require the secpath, so it should not be needed anymore. However, in some of those places, the MPTCP extension has just been attached to the skb, so we cannot simply drop all extensions.

In the Linux kernel, the following vulnerability has been resolved:

ipc: fix to protect IPCS lookups using RCU

syzbot reported that it discovered a use-after-free vulnerability, 0

idr_for_each() is protected by rwsem, but this is not enough. If it is not protected by RCU read-critical region, when idr_for_each() calls radix_tree_node_free() through call_rcu() to free the radix_tree_node structure, the node will be freed immediately, and when reading the next node in radix_tree_for_each_slot(), the already freed memory may be read.

Therefore, we need to add code to make sure that idr_for_each() is protected within the RCU read-critical region when we call it in shm_destroy_orphaned().

In the Linux kernel, the following vulnerability has been resolved:

fbdev: Fix fb_set_var to prevent null-ptr-deref in fb_videomode_to_var

If fb_add_videomode() in fb_set_var() fails to allocate memory for fb_videomode, later it may lead to a null-ptr dereference in fb_videomode_to_var(), as the fb_info is registered while not having the mode in modelist that is expected to be there, i.e. the one that is described in fb_info->var.

================================================================ general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901 Call Trace: display_to_var+0x3a/0x7c0 drivers/video/fbdev/core/fbcon.c:929 fbcon_resize+0x3e2/0x8f0 drivers/video/fbdev/core/fbcon.c:2071 resize_screen drivers/tty/vt/vt.c:1176 [inline] vc_do_resize+0x53a/0x1170 drivers/tty/vt/vt.c:1263 fbcon_modechanged+0x3ac/0x6e0 drivers/video/fbdev/core/fbcon.c:2720 fbcon_update_vcs+0x43/0x60 drivers/video/fbdev/core/fbcon.c:2776 do_fb_ioctl+0x6d2/0x740 drivers/video/fbdev/core/fbmem.c:1128 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1203 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x67/0xd1 ================================================================

The reason is that fb_info->var is being modified in fb_set_var(), and then fb_videomode_to_var() is called. If it fails to add the mode to fb_info->modelist, fb_set_var() returns error, but does not restore the old value of fb_info->var. Restore fb_info->var on failure the same way it is done earlier in the function.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

In the Linux kernel, the following vulnerability has been resolved:

fbdev: Fix do_register_framebuffer to prevent null-ptr-deref in fb_videomode_to_var

If fb_add_videomode() in do_register_framebuffer() fails to allocate memory for fb_videomode, it will later lead to a null-ptr dereference in fb_videomode_to_var(), as the fb_info is registered while not having the mode in modelist that is expected to be there, i.e. the one that is described in fb_info->var.

================================================================ general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 1 PID: 30371 Comm: syz-executor.1 Not tainted 5.10.226-syzkaller #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:fb_videomode_to_var+0x24/0x610 drivers/video/fbdev/core/modedb.c:901 Call Trace: display_to_var+0x3a/0x7c0 drivers/video/fbdev/core/fbcon.c:929 fbcon_resize+0x3e2/0x8f0 drivers/video/fbdev/core/fbcon.c:2071 resize_screen drivers/tty/vt/vt.c:1176 [inline] vc_do_resize+0x53a/0x1170 drivers/tty/vt/vt.c:1263 fbcon_modechanged+0x3ac/0x6e0 drivers/video/fbdev/core/fbcon.c:2720 fbcon_update_vcs+0x43/0x60 drivers/video/fbdev/core/fbcon.c:2776 do_fb_ioctl+0x6d2/0x740 drivers/video/fbdev/core/fbmem.c:1128 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1203 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x67/0xd1 ================================================================

Even though fbcon_init() checks beforehand if fb_match_mode() in var_to_display() fails, it can not prevent the panic because fbcon_init() does not return error code. Considering this and the comment in the code about fb_match_mode() returning NULL - "This should not happen" - it is better to prevent registering the fb_info if its mode was not set successfully. Also move fb_add_videomode() closer to the beginning of do_register_framebuffer() to avoid having to do the cleanup on fail.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

In the Linux kernel, the following vulnerability has been resolved:

ext4: inline: fix len overflow in ext4_prepare_inline_data

When running the following code on an ext4 filesystem with inline_data feature enabled, it will lead to the bug below.

    fd = open("file1", O_RDWR | O_CREAT | O_TRUNC, 0666);
    ftruncate(fd, 30);
    pwrite(fd, "a", 1, (1UL << 40) + 5UL);

That happens because write_begin will succeed as when ext4_generic_write_inline_data calls ext4_prepare_inline_data, pos + len will be truncated, leading to ext4_prepare_inline_data parameter to be 6 instead of 0x10000000006.

Then, later when write_end is called, we hit:

    BUG_ON(pos + len > EXT4_I(inode)->i_inline_size);

at ext4_write_inline_data.

Fix it by using a loff_t type for the len parameter in ext4_prepare_inline_data instead of an unsigned int.

[ 44.545164] ------------[ cut here ]------------ [ 44.545530] kernel BUG at fs/ext4/inline.c:240! [ 44.545834] Oops: invalid opcode: 0000 [#1] SMP NOPTI [ 44.546172] CPU: 3 UID: 0 PID: 343 Comm: test Not tainted 6.15.0-rc2-00003-g9080916f4863 #45 PREEMPT(full) 112853fcebfdb93254270a7959841d2c6aa2c8bb [ 44.546523] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 44.546523] RIP: 0010:ext4_write_inline_data+0xfe/0x100 [ 44.546523] Code: 3c 0e 48 83 c7 48 48 89 de 5b 41 5c 41 5d 41 5e 41 5f 5d e9 e4 fa 43 01 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 0f 0b <0f> 0b 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 20 49 [ 44.546523] RSP: 0018:ffffb342008b79a8 EFLAGS: 00010216 [ 44.546523] RAX: 0000000000000001 RBX: ffff9329c579c000 RCX: 0000010000000006 [ 44.546523] RDX: 000000000000003c RSI: ffffb342008b79f0 RDI: ffff9329c158e738 [ 44.546523] RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 [ 44.546523] R10: 00007ffffffff000 R11: ffffffff9bd0d910 R12: 0000006210000000 [ 44.546523] R13: fffffc7e4015e700 R14: 0000010000000005 R15: ffff9329c158e738 [ 44.546523] FS: 00007f4299934740(0000) GS:ffff932a60179000(0000) knlGS:0000000000000000 [ 44.546523] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 44.546523] CR2: 00007f4299a1ec90 CR3: 0000000002886002 CR4: 0000000000770eb0 [ 44.546523] PKRU: 55555554 [ 44.546523] Call Trace: [ 44.546523] <TASK> [ 44.546523] ext4_write_inline_data_end+0x126/0x2d0 [ 44.546523] generic_perform_write+0x17e/0x270 [ 44.546523] ext4_buffered_write_iter+0xc8/0x170 [ 44.546523] vfs_write+0x2be/0x3e0 [ 44.546523] __x64_sys_pwrite64+0x6d/0xc0 [ 44.546523] do_syscall_64+0x6a/0xf0 [ 44.546523] ? __wake_up+0x89/0xb0 [ 44.546523] ? xas_find+0x72/0x1c0 [ 44.546523] ? next_uptodate_folio+0x317/0x330 [ 44.546523] ? set_pte_range+0x1a6/0x270 [ 44.546523] ? filemap_map_pages+0x6ee/0x840 [ 44.546523] ? ext4_setattr+0x2fa/0x750 [ 44.546523] ? do_pte_missing+0x128/0xf70 [ 44.546523] ? security_inode_post_setattr+0x3e/0xd0 [ 44.546523] ? ___pte_offset_map+0x19/0x100 [ 44.546523] ? handle_mm_fault+0x721/0xa10 [ 44.546523] ? do_user_addr_fault+0x197/0x730 [ 44.546523] ? do_syscall_64+0x76/0xf0 [ 44.546523] ? arch_exit_to_user_mode_prepare+0x1e/0x60 [ 44.546523] ? irqentry_exit_to_user_mode+0x79/0x90 [ 44.546523] entry_SYSCALL_64_after_hwframe+0x55/0x5d [ 44.546523] RIP: 0033:0x7f42999c6687 [ 44.546523] Code: 48 89 fa 4c 89 df e8 58 b3 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff [ 44.546523] RSP: 002b:00007ffeae4a7930 EFLAGS: 00000202 ORIG_RAX: 0000000000000012 [ 44.546523] RAX: ffffffffffffffda RBX: 00007f4299934740 RCX: 00007f42999c6687 [ 44.546523] RDX: 0000000000000001 RSI: 000055ea6149200f RDI: 0000000000000003 [ 44.546523] RBP: 00007ffeae4a79a0 R08: 0000000000000000 R09: 0000000000000000 [ 44.546523] R10: 0000010000000005 R11: 0000000000000202 R12: 0000 ---truncated---

In the Linux kernel, the following vulnerability has been resolved:

nfsd: Initialize ssc before laundromat_work to prevent NULL dereference

In nfs4_state_start_net(), laundromat_work may access nfsd_ssc through nfs4_laundromat -> nfsd4_ssc_expire_umount. If nfsd_ssc isn't initialized, this can cause NULL pointer dereference.

Normally the delayed start of laundromat_work allows sufficient time for nfsd_ssc initialization to complete. However, when the kernel waits too long for userspace responses (e.g. in nfs4_state_start_net -> nfsd4_end_grace -> nfsd4_record_grace_done -> nfsd4_cld_grace_done -> cld_pipe_upcall -> __cld_pipe_upcall -> wait_for_completion path), the delayed work may start before nfsd_ssc initialization finishes.

Fix this by moving nfsd_ssc initialization before starting laundromat_work.

In the Linux kernel, the following vulnerability has been resolved:

af_unix: Don't leave consecutive consumed OOB skbs.

Jann Horn reported a use-after-free in unix_stream_read_generic().

The following sequences reproduce the issue:

$ python3 from socket import * s1, s2 = socketpair(AF_UNIX, SOCK_STREAM) s1.send(b'x', MSG_OOB) s2.recv(1, MSG_OOB) # leave a consumed OOB skb s1.send(b'y', MSG_OOB) s2.recv(1, MSG_OOB) # leave a consumed OOB skb s1.send(b'z', MSG_OOB) s2.recv(1) # recv 'z' illegally s2.recv(1, MSG_OOB) # access 'z' skb (use-after-free)

Even though a user reads OOB data, the skb holding the data stays on the recv queue to mark the OOB boundary and break the next recv().

After the last send() in the scenario above, the sk2's recv queue has 2 leading consumed OOB skbs and 1 real OOB skb.

Then, the following happens during the next recv() without MSG_OOB

1. unix_stream_read_generic() peeks the first consumed OOB skb
2. manage_oob() returns the next consumed OOB skb
3. unix_stream_read_generic() fetches the next not-yet-consumed OOB skb
4. unix_stream_read_generic() reads and frees the OOB skb

, and the last recv(MSG_OOB) triggers KASAN splat.

The 3. above occurs because of the SO_PEEK_OFF code, which does not expect unix_skb_len(skb) to be 0, but this is true for such consumed OOB skbs.

while (skip >= unix_skb_len(skb)) { skip -= unix_skb_len(skb); skb = skb_peek_next(skb, &sk->sk_receive_queue); ... }

In addition to this use-after-free, there is another issue that ioctl(SIOCATMARK) does not function properly with consecutive consumed OOB skbs.

So, nothing good comes out of such a situation.

Instead of complicating manage_oob(), ioctl() handling, and the next ECONNRESET fix by introducing a loop for consecutive consumed OOB skbs, let's not leave such consecutive OOB unnecessarily.

Now, while receiving an OOB skb in unix_stream_recv_urg(), if its previous skb is a consumed OOB skb, it is freed.

0: BUG: KASAN: slab-use-after-free in unix_stream_read_actor (net/unix/af_unix.c:3027) Read of size 4 at addr ffff888106ef2904 by task python3/315

CPU: 2 UID: 0 PID: 315 Comm: python3 Not tainted 6.16.0-rc1-00407-gec315832f6f9 #8 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-4.fc42 04/01/2014 Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:122) print_report (mm/kasan/report.c:409 mm/kasan/report.c:521) kasan_report (mm/kasan/report.c:636) unix_stream_read_actor (net/unix/af_unix.c:3027) unix_stream_read_generic (net/unix/af_unix.c:2708 net/unix/af_unix.c:2847) unix_stream_recvmsg (net/unix/af_unix.c:3048) sock_recvmsg (net/socket.c:1063 (discriminator 20) net/socket.c:1085 (discriminator 20)) __sys_recvfrom (net/socket.c:2278) __x64_sys_recvfrom (net/socket.c:2291 (discriminator 1) net/socket.c:2287 (discriminator 1) net/socket.c:2287 (discriminator 1)) do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1)) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) RIP: 0033:0x7f8911fcea06 Code: 5d e8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 75 19 83 e2 39 83 fa 08 75 11 e8 26 ff ff ff 66 0f 1f 44 00 00 48 8b 45 10 0f 05 <48> 8b 5d f8 c9 c3 0f 1f 40 00 f3 0f 1e fa 55 48 89 e5 48 83 ec 08 RSP: 002b:00007fffdb0dccb0 EFLAGS: 00000202 ORIG_RAX: 000000000000002d RAX: ffffffffffffffda RBX: 00007fffdb0dcdc8 RCX: 00007f8911fcea06 RDX: 0000000000000001 RSI: 00007f8911a5e060 RDI: 0000000000000006 RBP: 00007fffdb0dccd0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000202 R12: 00007f89119a7d20 R13: ffffffffc4653600 R14: 0000000000000000 R15: 0000000000000000 </TASK>

Allocated by task 315: kasan_save_stack (mm/kasan/common.c:48) kasan_save_track (mm/kasan/common.c:60 (discriminator 1) mm/kasan/common.c:69 (discriminator 1)) __kasan_slab_alloc (mm/kasan/common.c:348) kmem_cache_alloc_ ---truncated---

In the Linux kernel, the following vulnerability has been resolved:

bpf: Avoid __bpf_prog_ret0_warn when jit fails

syzkaller reported an issue:

WARNING: CPU: 3 PID: 217 at kernel/bpf/core.c:2357 __bpf_prog_ret0_warn+0xa/0x20 kernel/bpf/core.c:2357 Modules linked in: CPU: 3 UID: 0 PID: 217 Comm: kworker/u32:6 Not tainted 6.15.0-rc4-syzkaller-00040-g8bac8898fe39 RIP: 0010:__bpf_prog_ret0_warn+0xa/0x20 kernel/bpf/core.c:2357 Call Trace: <TASK> bpf_dispatcher_nop_func include/linux/bpf.h:1316 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] cls_bpf_classify+0x74a/0x1110 net/sched/cls_bpf.c:105 ...

When creating bpf program, 'fp->jit_requested' depends on bpf_jit_enable. This issue is triggered because of CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is set to 1, causing the arch to attempt JIT the prog, but jit failed due to FAULT_INJECTION. As a result, incorrectly treats the program as valid, when the program runs it calls __bpf_prog_ret0_warn and triggers the WARN_ON_ONCE(1).

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix WARN() in get_bpf_raw_tp_regs

syzkaller reported an issue:

WARNING: CPU: 3 PID: 5971 at kernel/trace/bpf_trace.c:1861 get_bpf_raw_tp_regs+0xa4/0x100 kernel/trace/bpf_trace.c:1861 Modules linked in: CPU: 3 UID: 0 PID: 5971 Comm: syz-executor205 Not tainted 6.15.0-rc5-syzkaller-00038-g707df3375124 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:get_bpf_raw_tp_regs+0xa4/0x100 kernel/trace/bpf_trace.c:1861 RSP: 0018:ffffc90003636fa8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffffff81c6bc4c RDX: ffff888032efc880 RSI: ffffffff81c6bc83 RDI: 0000000000000005 RBP: ffff88806a730860 R08: 0000000000000005 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000004 R13: 0000000000000001 R14: ffffc90003637008 R15: 0000000000000900 FS: 0000000000000000(0000) GS:ffff8880d6cdf000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7baee09130 CR3: 0000000029f5a000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> _bpfget_stack_raw_tp kernel/trace/bpf_trace.c:1934 [inline] bpf_get_stack_raw_tp+0x24/0x160 kernel/trace/bpf_trace.c:1931 bpf_prog_ec3b2eefa702d8d3+0x43/0x47 bpf_dispatcher_nop_func include/linux/bpf.h:1316 [inline] bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2363 [inline] bpf_trace_run3+0x23f/0x5a0 kernel/trace/bpf_trace.c:2405 __bpf_trace_mmap_lock_acquire_returned+0xfc/0x140 include/trace/events/mmap_lock.h:47 __traceiter_mmap_lock_acquire_returned+0x79/0xc0 include/trace/events/mmap_lock.h:47 __do_trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:47 [inline] trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:47 [inline] __mmap_lock_do_trace_acquire_returned+0x138/0x1f0 mm/mmap_lock.c:35 __mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline] mmap_read_trylock include/linux/mmap_lock.h:204 [inline] stack_map_get_build_id_offset+0x535/0x6f0 kernel/bpf/stackmap.c:157 __bpf_get_stack+0x307/0xa10 kernel/bpf/stackmap.c:483 _bpfget_stack kernel/bpf/stackmap.c:499 [inline] bpf_get_stack+0x32/0x40 kernel/bpf/stackmap.c:496 __bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1941 [inline] bpf_get_stack_raw_tp+0x124/0x160 kernel/trace/bpf_trace.c:1931 bpf_prog_ec3b2eefa702d8d3+0x43/0x47

Tracepoint like trace_mmap_lock_acquire_returned may cause nested call as the corner case show above, which will be resolved with more general method in the future. As a result, WARN_ON_ONCE will be triggered. As Alexei suggested, remove the WARN_ON_ONCE first.

In the Linux kernel, the following vulnerability has been resolved:

fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod()

In fb_find_mode_cvt(), iff mode->refresh somehow happens to be 0x80000000, cvt.f_refresh will become 0 when multiplying it by 2 due to overflow. It's then passed to fb_cvt_hperiod(), where it's used as a divider -- division by 0 will result in kernel oops. Add a sanity check for cvt.f_refresh to avoid such overflow...

Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool.

In the Linux kernel, the following vulnerability has been resolved:

software node: Correct a OOB check in software_node_get_reference_args()

software_node_get_reference_args() wants to get @index-th element, so the property value requires at least '(index + 1) * sizeof(*ref)' bytes but that can not be guaranteed by current OOB check, and may cause OOB for malformed property.

Fix by using as OOB check '((index + 1) * sizeof(*ref) > prop->length)'.

In the Linux kernel, the following vulnerability has been resolved:

net/sched: Always pass notifications when child class becomes empty

Certain classful qdiscs may invoke their classes' dequeue handler on an enqueue operation. This may unexpectedly empty the child qdisc and thus make an in-flight class passive via qlen_notify(). Most qdiscs do not expect such behaviour at this point in time and may re-activate the class eventually anyways which will lead to a use-after-free.

The referenced fix commit attempted to fix this behavior for the HFSC case by moving the backlog accounting around, though this turned out to be incomplete since the parent's parent may run into the issue too. The following reproducer demonstrates this use-after-free:

tc qdisc add dev lo root handle 1: drr
tc filter add dev lo parent 1: basic classid 1:1
tc class add dev lo parent 1: classid 1:1 drr
tc qdisc add dev lo parent 1:1 handle 2: hfsc def 1
tc class add dev lo parent 2: classid 2:1 hfsc rt m1 8 d 1 m2 0
tc qdisc add dev lo parent 2:1 handle 3: netem
tc qdisc add dev lo parent 3:1 handle 4: blackhole

echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888
tc class delete dev lo classid 1:1
echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888

Since backlog accounting issues leading to a use-after-frees on stale class pointers is a recurring pattern at this point, this patch takes a different approach. Instead of trying to fix the accounting, the patch ensures that qdisc_tree_reduce_backlog always calls qlen_notify when the child qdisc is empty. This solves the problem because deletion of qdiscs always involves a call to qdisc_reset() and / or qdisc_purge_queue() which ultimately resets its qlen to 0 thus causing the following qdisc_tree_reduce_backlog() to report to the parent. Note that this may call qlen_notify on passive classes multiple times. This is not a problem after the recent patch series that made all the classful qdiscs qlen_notify() handlers idempotent.

In the Linux kernel, the following vulnerability has been resolved:

maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate()

Temporarily clear the preallocation flag when explicitly requesting allocations. Pre-existing allocations are already counted against the request through mas_node_count_gfp(), but the allocations will not happen if the MA_STATE_PREALLOC flag is set. This flag is meant to avoid re-allocating in bulk allocation mode, and to detect issues with preallocation calculations.

The MA_STATE_PREALLOC flag should also always be set on zero allocations so that detection of underflow allocations will print a WARN_ON() during consumption.

User visible effect of this flaw is a WARN_ON() followed by a null pointer dereference when subsequent requests for larger number of nodes is ignored, such as the vma merge retry in mmap_region() caused by drivers altering the vma flags (which happens in v6.6, at least)

In the Linux kernel, the following vulnerability has been resolved:

NFSv4/pNFS: Fix a race to wake on NFS_LAYOUT_DRAIN

We found a few different systems hung up in writeback waiting on the same page lock, and one task waiting on the NFS_LAYOUT_DRAIN bit in pnfs_update_layout(), however the pnfs_layout_hdr's plh_outstanding count was zero.

It seems most likely that this is another race between the waiter and waker similar to commit ed0172af5d6f ("SUNRPC: Fix a race to wake a sync task"). Fix it up by applying the advised barrier.

In the Linux kernel, the following vulnerability has been resolved:

nfs: Clean up /proc/net/rpc/nfs when nfs_fs_proc_net_init() fails.

syzbot reported a warning below [1] following a fault injection in nfs_fs_proc_net_init(). 0

When nfs_fs_proc_net_init() fails, /proc/net/rpc/nfs is not removed.

Later, rpc_proc_exit() tries to remove /proc/net/rpc, and the warning is logged as the directory is not empty.

Let's handle the error of nfs_fs_proc_net_init() properly.

0: FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 UID: 0 PID: 6120 Comm: syz.2.27 Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:123) should_fail_ex (lib/fault-inject.c:73 lib/fault-inject.c:174) should_failslab (mm/failslab.c:46) kmem_cache_alloc_noprof (mm/slub.c:4178 mm/slub.c:4204) __proc_create (fs/proc/generic.c:427) proc_create_reg (fs/proc/generic.c:554) proc_create_net_data (fs/proc/proc_net.c:120) nfs_fs_proc_net_init (fs/nfs/client.c:1409) nfs_net_init (fs/nfs/inode.c:2600) ops_init (net/core/net_namespace.c:138) setup_net (net/core/net_namespace.c:443) copy_net_ns (net/core/net_namespace.c:576) create_new_namespaces (kernel/nsproxy.c:110) unshare_nsproxy_namespaces (kernel/nsproxy.c:218 (discriminator 4)) ksys_unshare (kernel/fork.c:3123) __x64_sys_unshare (kernel/fork.c:3190) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) </TASK>

[1]: remove_proc_entry: removing non-empty directory 'net/rpc', leaking at least 'nfs' WARNING: CPU: 1 PID: 6120 at fs/proc/generic.c:727 remove_proc_entry+0x45e/0x530 fs/proc/generic.c:727 Modules linked in: CPU: 1 UID: 0 PID: 6120 Comm: syz.2.27 Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:remove_proc_entry+0x45e/0x530 fs/proc/generic.c:727 Code: 3c 02 00 0f 85 85 00 00 00 48 8b 93 d8 00 00 00 4d 89 f0 4c 89 e9 48 c7 c6 40 ba a2 8b 48 c7 c7 60 b9 a2 8b e8 33 81 1d ff 90 <0f> 0b 90 90 e9 5f fe ff ff e8 04 69 5e ff 90 48 b8 00 00 00 00 00 RSP: 0018:ffffc90003637b08 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff88805f534140 RCX: ffffffff817a92c8 RDX: ffff88807da99e00 RSI: ffffffff817a92d5 RDI: 0000000000000001 RBP: ffff888033431ac0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff888033431a00 R13: ffff888033431ae4 R14: ffff888033184724 R15: dffffc0000000000 FS: 0000555580328500(0000) GS:ffff888124a62000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f71733743e0 CR3: 000000007f618000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> sunrpc_exit_net+0x46/0x90 net/sunrpc/sunrpc_syms.c:76 ops_exit_list net/core/net_namespace.c:200 [inline] ops_undo_list+0x2eb/0xab0 net/core/net_namespace.c:253 setup_net+0x2e1/0x510 net/core/net_namespace.c:457 copy_net_ns+0x2a6/0x5f0 net/core/net_namespace.c:574 create_new_namespaces+0x3ea/0xa90 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:218 ksys_unshare+0x45b/0xa40 kernel/fork.c:3121 __do_sys_unshare kernel/fork.c:3192 [inline] __se_sys_unshare kernel/fork.c:3190 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3190 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa1a6b8e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c ---truncated---

In the Linux kernel, the following vulnerability has been resolved:

nfsd: nfsd4_spo_must_allow() must check this is a v4 compound request

If the request being processed is not a v4 compound request, then examining the cstate can have undefined results.

This patch adds a check that the rpc procedure being executed (rq_procinfo) is the NFSPROC4_COMPOUND procedure.

In the Linux kernel, the following vulnerability has been resolved:

md/md-bitmap: fix GPF in bitmap_get_stats()

The commit message of commit 6ec1f0239485 ("md/md-bitmap: fix stats collection for external bitmaps") states:

Remove the external bitmap check as the statistics should be
available regardless of bitmap storage location.

Return -EINVAL only for invalid bitmap with no storage (neither in
superblock nor in external file).

But, the code does not adhere to the above, as it does only check for a valid super-block for "internal" bitmaps. Hence, we observe:

Oops: GPF, probably for non-canonical address 0x1cd66f1f40000028 RIP: 0010:bitmap_get_stats+0x45/0xd0 Call Trace:

seq_read_iter+0x2b9/0x46a seq_read+0x12f/0x180 proc_reg_read+0x57/0xb0 vfs_read+0xf6/0x380 ksys_read+0x6d/0xf0 do_syscall_64+0x8c/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

We fix this by checking the existence of a super-block for both the internal and external case.

In the Linux kernel, the following vulnerability has been resolved:

net/sched: Abort __tc_modify_qdisc if parent class does not exist

Lion's patch [1] revealed an ancient bug in the qdisc API. Whenever a user creates/modifies a qdisc specifying as a parent another qdisc, the qdisc API will, during grafting, detect that the user is not trying to attach to a class and reject. However grafting is performed after qdisc_create (and thus the qdiscs' init callback) is executed. In qdiscs that eventually call qdisc_tree_reduce_backlog during init or change (such as fq, hhf, choke, etc), an issue arises. For example, executing the following commands:

sudo tc qdisc add dev lo root handle a: htb default 2 sudo tc qdisc add dev lo parent a: handle beef fq

Qdiscs such as fq, hhf, choke, etc unconditionally invoke qdisc_tree_reduce_backlog() in their control path init() or change() which then causes a failure to find the child class; however, that does not stop the unconditional invocation of the assumed child qdisc's qlen_notify with a null class. All these qdiscs make the assumption that class is non-null.

The solution is ensure that qdisc_leaf() which looks up the parent class, and is invoked prior to qdisc_create(), should return failure on not finding the class. In this patch, we leverage qdisc_leaf to return ERR_PTRs whenever the parentid doesn't correspond to a class, so that we can detect it earlier on and abort before qdisc_create is called.

[1] https://lore.kernel.org/netdev/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com/

In the Linux kernel, the following vulnerability has been resolved:

netlink: Fix wraparounds of sk->sk_rmem_alloc.

Netlink has this pattern in some places

if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) atomic_add(skb->truesize, &sk->sk_rmem_alloc);

, which has the same problem fixed by commit 5a465a0da13e ("udp: Fix multiple wraparounds of sk->sk_rmem_alloc.").

For example, if we set INT_MAX to SO_RCVBUFFORCE, the condition is always false as the two operands are of int.

Then, a single socket can eat as many skb as possible until OOM happens, and we can see multiple wraparounds of sk->sk_rmem_alloc.

Let's fix it by using atomic_add_return() and comparing the two variables as unsigned int.

Before: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Local Address:Port Peer Address:Port -1668710080 0 rtnl:nl_wraparound/293 *

After: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Local Address:Port Peer Address:Port 2147483072 0 rtnl:nl_wraparound/290 * ^ `--- INT_MAX - 576

In the Linux kernel, the following vulnerability has been resolved:

perf: Revert to requiring CAP_SYS_ADMIN for uprobes

Jann reports that uprobes can be used destructively when used in the middle of an instruction. The kernel only verifies there is a valid instruction at the requested offset, but due to variable instruction length cannot determine if this is an instruction as seen by the intended execution stream.

Additionally, Mark Rutland notes that on architectures that mix data in the text segment (like arm64), a similar things can be done if the data word is 'mistaken' for an instruction.

As such, require CAP_SYS_ADMIN for uprobes.

In the Linux kernel, the following vulnerability has been resolved:

net/sched: Return NULL when htb_lookup_leaf encounters an empty rbtree

htb_lookup_leaf has a BUG_ON that can trigger with the following:

tc qdisc del dev lo root tc qdisc add dev lo root handle 1: htb default 1 tc class add dev lo parent 1: classid 1:1 htb rate 64bit tc qdisc add dev lo parent 1:1 handle 2: netem tc qdisc add dev lo parent 2:1 handle 3: blackhole ping -I lo -c1 -W0.001 127.0.0.1

The root cause is the following:

1. htb_dequeue calls htb_dequeue_tree which calls the dequeue handler on the selected leaf qdisc
2. netem_dequeue calls enqueue on the child qdisc
3. blackhole_enqueue drops the packet and returns a value that is not just NET_XMIT_SUCCESS
4. Because of this, netem_dequeue calls qdisc_tree_reduce_backlog, and since qlen is now 0, it calls htb_qlen_notify -> htb_deactivate -> htb_deactiviate_prios -> htb_remove_class_from_row -> htb_safe_rb_erase
5. As this is the only class in the selected hprio rbtree, __rb_change_child in __rb_erase_augmented sets the rb_root pointer to NULL
6. Because blackhole_dequeue returns NULL, netem_dequeue returns NULL, which causes htb_dequeue_tree to call htb_lookup_leaf with the same hprio rbtree, and fail the BUG_ON

The function graph for this scenario is shown here: 0) | htb_enqueue() { 0) + 13.635 us | netem_enqueue(); 0) 4.719 us | htb_activate_prios(); 0) # 2249.199 us | } 0) | htb_dequeue() { 0) 2.355 us | htb_lookup_leaf(); 0) | netem_dequeue() { 0) + 11.061 us | blackhole_enqueue(); 0) | qdisc_tree_reduce_backlog() { 0) | qdisc_lookup_rcu() { 0) 1.873 us | qdisc_match_from_root(); 0) 6.292 us | } 0) 1.894 us | htb_search(); 0) | htb_qlen_notify() { 0) 2.655 us | htb_deactivate_prios(); 0) 6.933 us | } 0) + 25.227 us | } 0) 1.983 us | blackhole_dequeue(); 0) + 86.553 us | } 0) # 2932.761 us | qdisc_warn_nonwc(); 0) | htb_lookup_leaf() { 0) | BUG_ON();

The full original bug report can be seen here [1].

We can fix this just by returning NULL instead of the BUG_ON, as htb_dequeue_tree returns NULL when htb_lookup_leaf returns NULL.

[1] https://lore.kernel.org/netdev/pF5XOOIim0IuEfhI-SOxTgRvNoDwuux7UHKnE_Y5-zVd4wmGvNk2ceHjKb8ORnzw0cGwfmVu42g9dL7XyJLf1NEzaztboTWcm0Ogxuojoeo=@willsroot.io/

In the Linux kernel, the following vulnerability has been resolved:

net: vlan: fix VLAN 0 refcount imbalance of toggling filtering during runtime

Assuming the "rx-vlan-filter" feature is enabled on a net device, the 8021q module will automatically add or remove VLAN 0 when the net device is put administratively up or down, respectively. There are a couple of problems with the above scheme.

The first problem is a memory leak that can happen if the "rx-vlan-filter" feature is disabled while the device is running:

# ip link add bond1 up type bond mode 0 # ethtool -K bond1 rx-vlan-filter off # ip link del dev bond1

When the device is put administratively down the "rx-vlan-filter" feature is disabled, so the 8021q module will not remove VLAN 0 and the memory will be leaked [1].

Another problem that can happen is that the kernel can automatically delete VLAN 0 when the device is put administratively down despite not adding it when the device was put administratively up since during that time the "rx-vlan-filter" feature was disabled. null-ptr-unref or bug_on[2] will be triggered by unregister_vlan_dev() for refcount imbalance if toggling filtering during runtime:

$ ip link add bond0 type bond mode 0 $ ip link add link bond0 name vlan0 type vlan id 0 protocol 802.1q $ ethtool -K bond0 rx-vlan-filter off $ ifconfig bond0 up $ ethtool -K bond0 rx-vlan-filter on $ ifconfig bond0 down $ ip link del vlan0

Root cause is as below: step1: add vlan0 for real_dev, such as bond, team. register_vlan_dev vlan_vid_add(real_dev,htons(ETH_P_8021Q),0) //refcnt=1 step2: disable vlan filter feature and enable real_dev step3: change filter from 0 to 1 vlan_device_event vlan_filter_push_vids ndo_vlan_rx_add_vid //No refcnt added to real_dev vlan0 step4: real_dev down vlan_device_event vlan_vid_del(dev, htons(ETH_P_8021Q), 0); //refcnt=0 vlan_info_rcu_free //free vlan0 step5: delete vlan0 unregister_vlan_dev BUG_ON(!vlan_info); //vlan_info is null

Fix both problems by noting in the VLAN info whether VLAN 0 was automatically added upon NETDEV_UP and based on that decide whether it should be deleted upon NETDEV_DOWN, regardless of the state of the "rx-vlan-filter" feature.

In the Linux kernel, the following vulnerability has been resolved:

tls: always refresh the queue when reading sock

After recent changes in net-next TCP compacts skbs much more aggressively. This unearthed a bug in TLS where we may try to operate on an old skb when checking if all skbs in the queue have matching decrypt state and geometry.

BUG: KASAN: slab-use-after-free in tls_strp_check_rcv+0x898/0x9a0 [tls]
(net/tls/tls_strp.c:436 net/tls/tls_strp.c:530 net/tls/tls_strp.c:544)
Read of size 4 at addr ffff888013085750 by task tls/13529

CPU: 2 UID: 0 PID: 13529 Comm: tls Not tainted 6.16.0-rc5-virtme
Call Trace:
 kasan_report+0xca/0x100
 tls_strp_check_rcv+0x898/0x9a0 [tls]
 tls_rx_rec_wait+0x2c9/0x8d0 [tls]
 tls_sw_recvmsg+0x40f/0x1aa0 [tls]
 inet_recvmsg+0x1c3/0x1f0

Always reload the queue, fast path is to have the record in the queue when we wake, anyway (IOW the path going down "if !strp->stm.full_len").

In the Linux kernel, the following vulnerability has been resolved:

net/sched: sch_qfq: Fix race condition on qfq_aggregate

A race condition can occur when 'agg' is modified in qfq_change_agg (called during qfq_enqueue) while other threads access it concurrently. For example, qfq_dump_class may trigger a NULL dereference, and qfq_delete_class may cause a use-after-free.

This patch addresses the issue by:

1. Moved qfq_destroy_class into the critical section.

2. Added sch_tree_lock protection to qfq_dump_class and qfq_dump_class_stats.

In the Linux kernel, the following vulnerability has been resolved:

do_change_type(): refuse to operate on unmounted/not ours mounts

Ensure that propagation settings can only be changed for mounts located in the caller's mount namespace. This change aligns permission checking with the rest of mount(2).

In the Linux kernel, the following vulnerability has been resolved:

clone_private_mnt(): make sure that caller has CAP_SYS_ADMIN in the right userns

What we want is to verify there is that clone won't expose something hidden by a mount we wouldn't be able to undo. "Wouldn't be able to undo" may be a result of MNT_LOCKED on a child, but it may also come from lacking admin rights in the userns of the namespace mount belongs to.

clone_private_mnt() checks the former, but not the latter.

There's a number of rather confusing CAP_SYS_ADMIN checks in various userns during the mount, especially with the new mount API; they serve different purposes and in case of clone_private_mnt() they usually, but not always end up covering the missing check mentioned above.

In the Linux kernel, the following vulnerability has been resolved:

eventpoll: Fix semi-unbounded recursion

Ensure that epoll instances can never form a graph deeper than EP_MAX_NESTS+1 links.

Currently, ep_loop_check_proc() ensures that the graph is loop-free and does some recursion depth checks, but those recursion depth checks don't limit the depth of the resulting tree for two reasons:

• They don't look upwards in the tree.
• If there are multiple downwards paths of different lengths, only one of the paths is actually considered for the depth check since commit 28d82dc1c4ed ("epoll: limit paths").

Essentially, the current recursion depth check in ep_loop_check_proc() just serves to prevent it from recursing too deeply while checking for loops.

A more thorough check is done in reverse_path_check() after the new graph edge has already been created; this checks, among other things, that no paths going upwards from any non-epoll file with a length of more than 5 edges exist. However, this check does not apply to non-epoll files.

As a result, it is possible to recurse to a depth of at least roughly 500, tested on v6.15. (I am unsure if deeper recursion is possible; and this may have changed with commit 8c44dac8add7 ("eventpoll: Fix priority inversion problem").)

To fix it:

1. In ep_loop_check_proc(), note the subtree depth of each visited node, and use subtree depths for the total depth calculation even when a subtree has already been visited.
2. Add ep_get_upwards_depth_proc() for similarly determining the maximum depth of an upwards walk.
3. In ep_loop_check(), use these values to limit the total path length between epoll nodes to EP_MAX_NESTS edges.

In the Linux kernel, the following vulnerability has been resolved:

fbdev: Fix vmalloc out-of-bounds write in fast_imageblit

This issue triggers when a userspace program does an ioctl FBIOPUT_CON2FBMAP by passing console number and frame buffer number. Ideally this maps console to frame buffer and updates the screen if console is visible.

As part of mapping it has to do resize of console according to frame buffer info. if this resize fails and returns from vc_do_resize() and continues further. At this point console and new frame buffer are mapped and sets display vars. Despite failure still it continue to proceed updating the screen at later stages where vc_data is related to previous frame buffer and frame buffer info and display vars are mapped to new frame buffer and eventully leading to out-of-bounds write in fast_imageblit(). This bheviour is excepted only when fg_console is equal to requested console which is a visible console and updates screen with invalid struct references in fbcon_putcs().

In the Linux kernel, the following vulnerability has been resolved:

pNFS: Fix uninited ptr deref in block/scsi layout

The error occurs on the third attempt to encode extents. When function ext_tree_prepare_commit() reallocates a larger buffer to retry encoding extents, the "layoutupdate_pages" page array is initialized only after the retry loop. But ext_tree_free_commitdata() is called on every iteration and tries to put pages in the array, thus dereferencing uninitialized pointers.

An additional problem is that there is no limit on the maximum possible buffer_size. When there are too many extents, the client may create a layoutcommit that is larger than the maximum possible RPC size accepted by the server.

During testing, we observed two typical scenarios. First, one memory page for extents is enough when we work with small files, append data to the end of the file, or preallocate extents before writing. But when we fill a new large file without preallocating, the number of extents can be huge, and counting the number of written extents in ext_tree_encode_commit() does not help much. Since this number increases even more between unlocking and locking of ext_tree, the reallocated buffer may not be large enough again and again.

In the Linux kernel, the following vulnerability has been resolved:

ext4: do not BUG when INLINE_DATA_FL lacks system.data xattr

A syzbot fuzzed image triggered a BUG_ON in ext4_update_inline_data() when an inode had the INLINE_DATA_FL flag set but was missing the system.data extended attribute.

Since this can happen due to a maiciouly fuzzed file system, we shouldn't BUG, but rather, report it as a corrupted file system.

Add similar replacements of BUG_ON with EXT4_ERROR_INODE() ii ext4_create_inline_data() and ext4_inline_data_truncate().

In the Linux kernel, the following vulnerability has been resolved:

fbdev: fix potential buffer overflow in do_register_framebuffer()

The current implementation may lead to buffer overflow when: 1. Unregistration creates NULL gaps in registered_fb[] 2. All array slots become occupied despite num_registered_fb < FB_MAX 3. The registration loop exceeds array bounds

Add boundary check to prevent registered_fb[FB_MAX] access.

In the Linux kernel, the following vulnerability has been resolved:

drbd: add missing kref_get in handle_write_conflicts

With two-primaries enabled, DRBD tries to detect "concurrent" writes and handle write conflicts, so that even if you write to the same sector simultaneously on both nodes, they end up with the identical data once the writes are completed.

In handling "superseeded" writes, we forgot a kref_get, resulting in a premature drbd_destroy_device and use after free, and further to kernel crashes with symptoms.

Relevance: No one should use DRBD as a random data generator, and apparently all users of "two-primaries" handle concurrent writes correctly on layer up. That is cluster file systems use some distributed lock manager, and live migration in virtualization environments stops writes on one node before starting writes on the other node.

Which means that other than for "test cases", this code path is never taken in real life.

FYI, in DRBD 9, things are handled differently nowadays. We still detect "write conflicts", but no longer try to be smart about them. We decided to disconnect hard instead: upper layers must not submit concurrent writes. If they do, that's their fault.

In the Linux kernel, the following vulnerability has been resolved:

netfilter: ctnetlink: fix refcount leak on table dump

There is a reference count leak in ctnetlink_dump_table(): if (res < 0) { nf_conntrack_get(&ct->ct_general); // HERE cb->args[1] = (unsigned long)ct; ...

While its very unlikely, its possible that ct == last. If this happens, then the refcount of ct was already incremented. This 2nd increment is never undone.

This prevents the conntrack object from being released, which in turn keeps prevents cnet->count from dropping back to 0.

This will then block the netns dismantle (or conntrack rmmod) as nf_conntrack_cleanup_net_list() will wait forever.

This can be reproduced by running conntrack_resize.sh selftest in a loop. It takes ~20 minutes for me on a preemptible kernel on average before I see a runaway kworker spinning in nf_conntrack_cleanup_net_list.

One fix would to change this to: if (res < 0) { if (ct != last) nf_conntrack_get(&ct->ct_general);

But this reference counting isn't needed in the first place. We can just store a cookie value instead.

A followup patch will do the same for ctnetlink_exp_dump_table, it looks to me as if this has the same problem and like ctnetlink_dump_table, we only need a 'skip hint', not the actual object so we can apply the same cookie strategy there as well.

In the Linux kernel, the following vulnerability has been resolved:

nfsd: handle get_client_locked() failure in nfsd4_setclientid_confirm()

Lei Lu recently reported that nfsd4_setclientid_confirm() did not check the return value from get_client_locked(). a SETCLIENTID_CONFIRM could race with a confirmed client expiring and fail to get a reference. That could later lead to a UAF.

Fix this by getting a reference early in the case where there is an extant confirmed client. If that fails then treat it as if there were no confirmed client found at all.

In the case where the unconfirmed client is expiring, just fail and return the result from get_client_locked().

In the Linux kernel, the following vulnerability has been resolved:

netlink: avoid infinite retry looping in netlink_unicast()

netlink_attachskb() checks for the socket's read memory allocation constraints. Firstly, it has:

rmem < READ_ONCE(sk->sk_rcvbuf)

to check if the just increased rmem value fits into the socket's receive buffer. If not, it proceeds and tries to wait for the memory under:

rmem + skb->truesize > READ_ONCE(sk->sk_rcvbuf)

The checks don't cover the case when skb->truesize + sk->sk_rmem_alloc is equal to sk->sk_rcvbuf. Thus the function neither successfully accepts these conditions, nor manages to reschedule the task - and is called in retry loop for indefinite time which is caught as:

rcu: INFO: rcu_sched self-detected stall on CPU rcu: 0-....: (25999 ticks this GP) idle=ef2/1/0x4000000000000000 softirq=262269/262269 fqs=6212 (t=26000 jiffies g=230833 q=259957) NMI backtrace for cpu 0 CPU: 0 PID: 22 Comm: kauditd Not tainted 5.10.240 #68 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc42 04/01/2014 Call Trace: <IRQ> dump_stack lib/dump_stack.c:120 nmi_cpu_backtrace.cold lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace lib/nmi_backtrace.c:62 rcu_dump_cpu_stacks kernel/rcu/tree_stall.h:335 rcu_sched_clock_irq.cold kernel/rcu/tree.c:2590 update_process_times kernel/time/timer.c:1953 tick_sched_handle kernel/time/tick-sched.c:227 tick_sched_timer kernel/time/tick-sched.c:1399 __hrtimer_run_queues kernel/time/hrtimer.c:1652 hrtimer_interrupt kernel/time/hrtimer.c:1717 __sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 asm_call_irq_on_stack arch/x86/entry/entry_64.S:808 </IRQ>

netlink_attachskb net/netlink/af_netlink.c:1234 netlink_unicast net/netlink/af_netlink.c:1349 kauditd_send_queue kernel/audit.c:776 kauditd_thread kernel/audit.c:897 kthread kernel/kthread.c:328 ret_from_fork arch/x86/entry/entry_64.S:304

Restore the original behavior of the check which commit in Fixes accidentally missed when restructuring the code.

Found by Linux Verification Center (linuxtesting.org).

In the Linux kernel, the following vulnerability has been resolved:

tracing: Limit access to parser->buffer when trace_get_user failed

When the length of the string written to set_ftrace_filter exceeds FTRACE_BUFF_MAX, the following KASAN alarm will be triggered:

BUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0 Read of size 1 at addr ffff0000d00bd5ba by task ash/165

CPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x34/0x50 (C) dump_stack_lvl+0xa0/0x158 print_address_description.constprop.0+0x88/0x398 print_report+0xb0/0x280 kasan_report+0xa4/0xf0 __asan_report_load1_noabort+0x20/0x30 strsep+0x18c/0x1b0 ftrace_process_regex.isra.0+0x100/0x2d8 ftrace_regex_release+0x484/0x618 __fput+0x364/0xa58 ____fput+0x28/0x40 task_work_run+0x154/0x278 do_notify_resume+0x1f0/0x220 el0_svc+0xec/0xf0 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x1ac/0x1b0

The reason is that trace_get_user will fail when processing a string longer than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0. Then an OOB access will be triggered in ftrace_regex_release-> ftrace_process_regex->strsep->strpbrk. We can solve this problem by limiting access to parser->buffer when trace_get_user failed.

In the Linux kernel, the following vulnerability has been resolved:

ftrace: Also allocate and copy hash for reading of filter files

Currently the reader of set_ftrace_filter and set_ftrace_notrace just adds the pointer to the global tracer hash to its iterator. Unlike the writer that allocates a copy of the hash, the reader keeps the pointer to the filter hashes. This is problematic because this pointer is static across function calls that release the locks that can update the global tracer hashes. This can cause UAF and similar bugs.

Allocate and copy the hash for reading the filter files like it is done for the writers. This not only fixes UAF bugs, but also makes the code a bit simpler as it doesn't have to differentiate when to free the iterator's hash between writers and readers.

In the Linux kernel, the following vulnerability has been resolved:

NFS: Fix a race when updating an existing write

After nfs_lock_and_join_requests() tests for whether the request is still attached to the mapping, nothing prevents a call to nfs_inode_remove_request() from succeeding until we actually lock the page group. The reason is that whoever called nfs_inode_remove_request() doesn't necessarily have a lock on the page group head.

So in order to avoid races, let's take the page group lock earlier in nfs_lock_and_join_requests(), and hold it across the removal of the request in nfs_inode_remove_request().

In the Linux kernel, the following vulnerability has been resolved:

serial: 8250: fix panic due to PSLVERR

When the PSLVERR_RESP_EN parameter is set to 1, the device generates an error response if an attempt is made to read an empty RBR (Receive Buffer Register) while the FIFO is enabled.

In serial8250_do_startup(), calling serial_port_out(port, UART_LCR, UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter function enables the FIFO via serial_out(p, UART_FCR, p->fcr). Execution proceeds to the serial_port_in(port, UART_RX). This satisfies the PSLVERR trigger condition.

When another CPU (e.g., using printk()) is accessing the UART (UART is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter dw8250_force_idle().

Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock to fix this issue.

Panic backtrace: [ 0.442336] Oops - unknown exception [#1] [ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a [ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e ... [ 0.442416] console_on_rootfs+0x26/0x70

In the Linux kernel, the following vulnerability has been resolved:

fs: Prevent file descriptor table allocations exceeding INT_MAX

When sysctl_nr_open is set to a very high value (for example, 1073741816 as set by systemd), processes attempting to use file descriptors near the limit can trigger massive memory allocation attempts that exceed INT_MAX, resulting in a WARNING in mm/slub.c:

WARNING: CPU: 0 PID: 44 at mm/slub.c:5027 __kvmalloc_node_noprof+0x21a/0x288

This happens because kvmalloc_array() and kvmalloc() check if the requested size exceeds INT_MAX and emit a warning when the allocation is not flagged with __GFP_NOWARN.

Specifically, when nr_open is set to 1073741816 (0x3ffffff8) and a process calls dup2(oldfd, 1073741880), the kernel attempts to allocate: - File descriptor array: 1073741880 * 8 bytes = 8,589,935,040 bytes - Multiple bitmaps: ~400MB - Total allocation size: > 8GB (exceeding INT_MAX = 2,147,483,647)

Reproducer: 1. Set /proc/sys/fs/nr_open to 1073741816: # echo 1073741816 > /proc/sys/fs/nr_open

1. Run a program that uses a high file descriptor: #include <unistd.h> #include <sys/resource.h>

int main() { struct rlimit rlim = {1073741824, 1073741824}; setrlimit(RLIMIT_NOFILE, &rlim); dup2(2, 1073741880); // Triggers the warning return 0; }

1. Observe WARNING in dmesg at mm/slub.c:5027

systemd commit a8b627a introduced automatic bumping of fs.nr_open to the maximum possible value. The rationale was that systems with memory control groups (memcg) no longer need separate file descriptor limits since memory is properly accounted. However, this change overlooked that:

1. The kernel's allocation functions still enforce INT_MAX as a maximum size regardless of memcg accounting
2. Programs and tests that legitimately test file descriptor limits can inadvertently trigger massive allocations
3. The resulting allocations (>8GB) are impractical and will always fail

systemd's algorithm starts with INT_MAX and keeps halving the value until the kernel accepts it. On most systems, this results in nr_open being set to 1073741816 (0x3ffffff8), which is just under 1GB of file descriptors.

While processes rarely use file descriptors near this limit in normal operation, certain selftests (like tools/testing/selftests/core/unshare_test.c) and programs that test file descriptor limits can trigger this issue.

Fix this by adding a check in alloc_fdtable() to ensure the requested allocation size does not exceed INT_MAX. This causes the operation to fail with -EMFILE instead of triggering a kernel warning and avoids the impractical >8GB memory allocation request.

In the Linux kernel, the following vulnerability has been resolved:

net: gso: Forbid IPv6 TSO with extensions on devices with only IPV6_CSUM

When performing Generic Segmentation Offload (GSO) on an IPv6 packet that contains extension headers, the kernel incorrectly requests checksum offload if the egress device only advertises NETIF_F_IPV6_CSUM feature, which has a strict contract: it supports checksum offload only for plain TCP or UDP over IPv6 and explicitly does not support packets with extension headers. The current GSO logic violates this contract by failing to disable the feature for packets with extension headers, such as those used in GREoIPv6 tunnels.

This violation results in the device being asked to perform an operation it cannot support, leading to a skb_warn_bad_offload warning and a collapse of network throughput. While device TSO/USO is correctly bypassed in favor of software GSO for these packets, the GSO stack must be explicitly told not to request checksum offload.

Mask NETIF_F_IPV6_CSUM, NETIF_F_TSO6 and NETIF_F_GSO_UDP_L4 in gso_features_check if the IPv6 header contains extension headers to compute checksum in software.

The exception is a BIG TCP extension, which, as stated in commit 68e068cabd2c6c53 ("net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets"): "The feature is only enabled on devices that support BIG TCP TSO. The header is only present for PF_PACKET taps like tcpdump, and not transmitted by physical devices."

kernel log output (truncated): WARNING: CPU: 1 PID: 5273 at net/core/dev.c:3535 skb_warn_bad_offload+0x81/0x140 ... Call Trace: <TASK> skb_checksum_help+0x12a/0x1f0 validate_xmit_skb+0x1a3/0x2d0 validate_xmit_skb_list+0x4f/0x80 sch_direct_xmit+0x1a2/0x380 __dev_xmit_skb+0x242/0x670 __dev_queue_xmit+0x3fc/0x7f0 ip6_finish_output2+0x25e/0x5d0 ip6_finish_output+0x1fc/0x3f0 ip6_tnl_xmit+0x608/0xc00 [ip6_tunnel] ip6gre_tunnel_xmit+0x1c0/0x390 [ip6_gre] dev_hard_start_xmit+0x63/0x1c0 __dev_queue_xmit+0x6d0/0x7f0 ip6_finish_output2+0x214/0x5d0 ip6_finish_output+0x1fc/0x3f0 ip6_xmit+0x2ca/0x6f0 ip6_finish_output+0x1fc/0x3f0 ip6_xmit+0x2ca/0x6f0 inet6_csk_xmit+0xeb/0x150 __tcp_transmit_skb+0x555/0xa80 tcp_write_xmit+0x32a/0xe90 tcp_sendmsg_locked+0x437/0x1110 tcp_sendmsg+0x2f/0x50 ... skb linear: 00000000: e4 3d 1a 7d ec 30 e4 3d 1a 7e 5d 90 86 dd 60 0e skb linear: 00000010: 00 0a 1b 34 3c 40 20 11 00 00 00 00 00 00 00 00 skb linear: 00000020: 00 00 00 00 00 12 20 11 00 00 00 00 00 00 00 00 skb linear: 00000030: 00 00 00 00 00 11 2f 00 04 01 04 01 01 00 00 00 skb linear: 00000040: 86 dd 60 0e 00 0a 1b 00 06 40 20 23 00 00 00 00 skb linear: 00000050: 00 00 00 00 00 00 00 00 00 12 20 23 00 00 00 00 skb linear: 00000060: 00 00 00 00 00 00 00 00 00 11 bf 96 14 51 13 f9 skb linear: 00000070: ae 27 a0 a8 2b e3 80 18 00 40 5b 6f 00 00 01 01 skb linear: 00000080: 08 0a 42 d4 50 d5 4b 70 f8 1a

In the Linux kernel, the following vulnerability has been resolved:

net: bridge: fix soft lockup in br_multicast_query_expired()

When set multicast_query_interval to a large value, the local variable 'time' in br_multicast_send_query() may overflow. If the time is smaller than jiffies, the timer will expire immediately, and then call mod_timer() again, which creates a loop and may trigger the following soft lockup issue.

watchdog: BUG: soft lockup - CPU#1 stuck for 221s! [rb_consumer:66] CPU: 1 UID: 0 PID: 66 Comm: rb_consumer Not tainted 6.16.0+ #259 PREEMPT(none) Call Trace: <IRQ> __netdev_alloc_skb+0x2e/0x3a0 br_ip6_multicast_alloc_query+0x212/0x1b70 __br_multicast_send_query+0x376/0xac0 br_multicast_send_query+0x299/0x510 br_multicast_query_expired.constprop.0+0x16d/0x1b0 call_timer_fn+0x3b/0x2a0 __run_timers+0x619/0x950 run_timer_softirq+0x11c/0x220 handle_softirqs+0x18e/0x560 __irq_exit_rcu+0x158/0x1a0 sysvec_apic_timer_interrupt+0x76/0x90 </IRQ>

This issue can be reproduced with: ip link add br0 type bridge echo 1 > /sys/class/net/br0/bridge/multicast_querier echo 0xffffffffffffffff > /sys/class/net/br0/bridge/multicast_query_interval ip link set dev br0 up

The multicast_startup_query_interval can also cause this issue. Similar to the commit 99b40610956a ("net: bridge: mcast: add and enforce query interval minimum"), add check for the query interval maximum to fix this issue.

In the Linux kernel, the following vulnerability has been resolved:

PCI: endpoint: Fix configfs group list head handling

Doing a list_del() on the epf_group field of struct pci_epf_driver in pci_epf_remove_cfs() is not correct as this field is a list head, not a list entry. This list_del() call triggers a KASAN warning when an endpoint function driver which has a configfs attribute group is torn down:

================================================================== BUG: KASAN: slab-use-after-free in pci_epf_remove_cfs+0x17c/0x198 Write of size 8 at addr ffff00010f4a0d80 by task rmmod/319

CPU: 3 UID: 0 PID: 319 Comm: rmmod Not tainted 6.16.0-rc2 #1 NONE Hardware name: Radxa ROCK 5B (DT) Call trace: show_stack+0x2c/0x84 (C) dump_stack_lvl+0x70/0x98 print_report+0x17c/0x538 kasan_report+0xb8/0x190 __asan_report_store8_noabort+0x20/0x2c pci_epf_remove_cfs+0x17c/0x198 pci_epf_unregister_driver+0x18/0x30 nvmet_pci_epf_cleanup_module+0x24/0x30 [nvmet_pci_epf] __arm64_sys_delete_module+0x264/0x424 invoke_syscall+0x70/0x260 el0_svc_common.constprop.0+0xac/0x230 do_el0_svc+0x40/0x58 el0_svc+0x48/0xdc el0t_64_sync_handler+0x10c/0x138 el0t_64_sync+0x198/0x19c ...

Remove this incorrect list_del() call from pci_epf_remove_cfs().

In the Linux kernel, the following vulnerability has been resolved:

soc: qcom: mdt_loader: Ensure we don't read past the ELF header

When the MDT loader is used in remoteproc, the ELF header is sanitized beforehand, but that's not necessary the case for other clients.

Validate the size of the firmware buffer to ensure that we don't read past the end as we iterate over the header. e_phentsize and e_shentsize are validated as well, to ensure that the assumptions about step size in the traversal are valid.

In the Linux kernel, the following vulnerability has been resolved:

block: avoid possible overflow for chunk_sectors check in blk_stack_limits()

In blk_stack_limits(), we check that the t->chunk_sectors value is a multiple of the t->physical_block_size value.

However, by finding the chunk_sectors value in bytes, we may overflow the unsigned int which holds chunk_sectors, so change the check to be based on sectors.

In the Linux kernel, the following vulnerability has been resolved:

NFS: Fix the setting of capabilities when automounting a new filesystem

Capabilities cannot be inherited when we cross into a new filesystem. They need to be reset to the minimal defaults, and then probed for again.

In the Linux kernel, the following vulnerability has been resolved:

fs: writeback: fix use-after-free in __mark_inode_dirty()

An use-after-free issue occurred when __mark_inode_dirty() get the bdi_writeback that was in the progress of switching.

CPU: 1 PID: 562 Comm: systemd-random- Not tainted 6.6.56-gb4403bd46a8e #1 ...... pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __mark_inode_dirty+0x124/0x418 lr : __mark_inode_dirty+0x118/0x418 sp : ffffffc08c9dbbc0 ........ Call trace: __mark_inode_dirty+0x124/0x418 generic_update_time+0x4c/0x60 file_modified+0xcc/0xd0 ext4_buffered_write_iter+0x58/0x124 ext4_file_write_iter+0x54/0x704 vfs_write+0x1c0/0x308 ksys_write+0x74/0x10c __arm64_sys_write+0x1c/0x28 invoke_syscall+0x48/0x114 el0_svc_common.constprop.0+0xc0/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x40/0xe4 el0t_64_sync_handler+0x120/0x12c el0t_64_sync+0x194/0x198

Root cause is:

___mark_inode_dirty inode_switch_wbs_work_fn

spin_lock(&inode->i_lock); inode_attach_wb locked_inode_to_wb_and_lock_list get inode->i_wb spin_unlock(&inode->i_lock); spin_lock(&wb->list_lock) spin_lock(&inode->i_lock) inode_io_list_move_locked spin_unlock(&wb->list_lock) spin_unlock(&inode->i_lock) spin_lock(&old_wb->list_lock) inode_do_switch_wbs spin_lock(&inode->i_lock) inode->i_wb = new_wb spin_unlock(&inode->i_lock) spin_unlock(&old_wb->list_lock) wb_put_many(old_wb, nr_switched) cgwb_release old wb released wb_wakeup_delayed() accesses wb, then trigger the use-after-free issue

Fix this race condition by holding inode spinlock until wb_wakeup_delayed() finished.

In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix smbdirect_recv_io leak in smbd_negotiate() error path

During tests of another unrelated patch I was able to trigger this error: Objects remaining on __kmem_cache_shutdown()

In the Linux kernel, the following vulnerability has been resolved:

crypto: af_alg - Set merge to zero early in af_alg_sendmsg

If an error causes af_alg_sendmsg to abort, ctx->merge may contain a garbage value from the previous loop. This may then trigger a crash on the next entry into af_alg_sendmsg when it attempts to do a merge that can't be done.

Fix this by setting ctx->merge to zero near the start of the loop.

In the Linux kernel, the following vulnerability has been resolved:

futex: Prevent use-after-free during requeue-PI

syzbot managed to trigger the following race:

T1 T2

futex_wait_requeue_pi() futex_do_wait() schedule() futex_requeue() futex_proxy_trylock_atomic() futex_requeue_pi_prepare() requeue_pi_wake_futex() futex_requeue_pi_complete() / preempt /

     * timeout/ signal wakes T1 *

futex_requeue_pi_wakeup_sync() // Q_REQUEUE_PI_LOCKED futex_hash_put() // back to userland, on stack futex_q is garbage

                                  /* back */
                                 wake_up_state(q->task, TASK_NORMAL);

In this scenario futex_wait_requeue_pi() is able to leave without using futex_q::lock_ptr for synchronization.

This can be prevented by reading futex_q::task before updating the futex_q::requeue_state. A reference on the task_struct is not needed because requeue_pi_wake_futex() is invoked with a spinlock_t held which implies a RCU read section.

Even if T1 terminates immediately after, the task_struct will remain valid during T2's wake_up_state(). A READ_ONCE on futex_q::task before futex_requeue_pi_complete() is enough because it ensures that the variable is read before the state is updated.

Read futex_q::task before updating the requeue state, use it for the following wakeup.

In the Linux kernel, the following vulnerability has been resolved:

crypto: af_alg - Fix incorrect boolean values in af_alg_ctx

Commit 1b34cbbf4f01 ("crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg") changed some fields from bool to 1-bit bitfields of type u32.

However, some assignments to these fields, specifically 'more' and 'merge', assign values greater than 1. These relied on C's implicit conversion to bool, such that zero becomes false and nonzero becomes true.

With a 1-bit bitfields of type u32 instead, mod 2 of the value is taken instead, resulting in 0 being assigned in some cases when 1 was intended.

Fix this by restoring the bool type.