| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-37876: netfs: Only create /proc/fs/netfs with CONFIG_PROC_FS |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| netfs: Only create /proc/fs/netfs with CONFIG_PROC_FS |
| |
| When testing a special config: |
| |
| CONFIG_NETFS_SUPPORTS=y |
| CONFIG_PROC_FS=n |
| |
| The system crashes with something like: |
| |
| [ 3.766197] ------------[ cut here ]------------ |
| [ 3.766484] kernel BUG at mm/mempool.c:560! |
| [ 3.766789] Oops: invalid opcode: 0000 [#1] SMP NOPTI |
| [ 3.767123] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W |
| [ 3.767777] Tainted: [W]=WARN |
| [ 3.767968] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), |
| [ 3.768523] RIP: 0010:mempool_alloc_slab.cold+0x17/0x19 |
| [ 3.768847] Code: 50 fe ff 58 5b 5d 41 5c 41 5d 41 5e 41 5f e9 93 95 13 00 |
| [ 3.769977] RSP: 0018:ffffc90000013998 EFLAGS: 00010286 |
| [ 3.770315] RAX: 000000000000002f RBX: ffff888100ba8640 RCX: 0000000000000000 |
| [ 3.770749] RDX: 0000000000000000 RSI: 0000000000000003 RDI: 00000000ffffffff |
| [ 3.771217] RBP: 0000000000092880 R08: 0000000000000000 R09: ffffc90000013828 |
| [ 3.771664] R10: 0000000000000001 R11: 00000000ffffffea R12: 0000000000092cc0 |
| [ 3.772117] R13: 0000000000000400 R14: ffff8881004b1620 R15: ffffea0004ef7e40 |
| [ 3.772554] FS: 0000000000000000(0000) GS:ffff8881b5f3c000(0000) knlGS:0000000000000000 |
| [ 3.773061] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| [ 3.773443] CR2: ffffffff830901b4 CR3: 0000000004296001 CR4: 0000000000770ef0 |
| [ 3.773884] PKRU: 55555554 |
| [ 3.774058] Call Trace: |
| [ 3.774232] <TASK> |
| [ 3.774371] mempool_alloc_noprof+0x6a/0x190 |
| [ 3.774649] ? _printk+0x57/0x80 |
| [ 3.774862] netfs_alloc_request+0x85/0x2ce |
| [ 3.775147] netfs_readahead+0x28/0x170 |
| [ 3.775395] read_pages+0x6c/0x350 |
| [ 3.775623] ? srso_alias_return_thunk+0x5/0xfbef5 |
| [ 3.775928] page_cache_ra_unbounded+0x1bd/0x2a0 |
| [ 3.776247] filemap_get_pages+0x139/0x970 |
| [ 3.776510] ? srso_alias_return_thunk+0x5/0xfbef5 |
| [ 3.776820] filemap_read+0xf9/0x580 |
| [ 3.777054] ? srso_alias_return_thunk+0x5/0xfbef5 |
| [ 3.777368] ? srso_alias_return_thunk+0x5/0xfbef5 |
| [ 3.777674] ? find_held_lock+0x32/0x90 |
| [ 3.777929] ? netfs_start_io_read+0x19/0x70 |
| [ 3.778221] ? netfs_start_io_read+0x19/0x70 |
| [ 3.778489] ? srso_alias_return_thunk+0x5/0xfbef5 |
| [ 3.778800] ? lock_acquired+0x1e6/0x450 |
| [ 3.779054] ? srso_alias_return_thunk+0x5/0xfbef5 |
| [ 3.779379] netfs_buffered_read_iter+0x57/0x80 |
| [ 3.779670] __kernel_read+0x158/0x2c0 |
| [ 3.779927] bprm_execve+0x300/0x7a0 |
| [ 3.780185] kernel_execve+0x10c/0x140 |
| [ 3.780423] ? __pfx_kernel_init+0x10/0x10 |
| [ 3.780690] kernel_init+0xd5/0x150 |
| [ 3.780910] ret_from_fork+0x2d/0x50 |
| [ 3.781156] ? __pfx_kernel_init+0x10/0x10 |
| [ 3.781414] ret_from_fork_asm+0x1a/0x30 |
| [ 3.781677] </TASK> |
| [ 3.781823] Modules linked in: |
| [ 3.782065] ---[ end trace 0000000000000000 ]--- |
| |
| This is caused by the following error path in netfs_init(): |
| |
| if (!proc_mkdir("fs/netfs", NULL)) |
| goto error_proc; |
| |
| Fix this by adding ifdef in netfs_main(), so that /proc/fs/netfs is only |
| created with CONFIG_PROC_FS. |
| |
| The Linux kernel CVE team has assigned CVE-2025-37876 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.8 with commit 7eb5b3e3a0a55f2d166ca949ef47ca6e0c704aab and fixed in 6.12.26 with commit 2ef6eea2efce01d1956ace483216f6b6e26330c9 |
| Issue introduced in 6.8 with commit 7eb5b3e3a0a55f2d166ca949ef47ca6e0c704aab and fixed in 6.14.5 with commit 6c4c5e0b96a90f2a11c378e66edc1f25165e10b6 |
| Issue introduced in 6.8 with commit 7eb5b3e3a0a55f2d166ca949ef47ca6e0c704aab and fixed in 6.15 with commit 40cb48eba3b4b79e110c1a35d33a48cac54507a2 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2025-37876 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| fs/netfs/main.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/2ef6eea2efce01d1956ace483216f6b6e26330c9 |
| https://git.kernel.org/stable/c/6c4c5e0b96a90f2a11c378e66edc1f25165e10b6 |
| https://git.kernel.org/stable/c/40cb48eba3b4b79e110c1a35d33a48cac54507a2 |
