| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-49932: btrfs: don't readahead the relocation inode on RST |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| btrfs: don't readahead the relocation inode on RST |
| |
| On relocation we're doing readahead on the relocation inode, but if the |
| filesystem is backed by a RAID stripe tree we can get ENOENT (e.g. due to |
| preallocated extents not being mapped in the RST) from the lookup. |
| |
| But readahead doesn't handle the error and submits invalid reads to the |
| device, causing an assertion in the scatter-gather list code: |
| |
| BTRFS info (device nvme1n1): balance: start -d -m -s |
| BTRFS info (device nvme1n1): relocating block group 6480920576 flags data|raid0 |
| BTRFS error (device nvme1n1): cannot find raid-stripe for logical [6481928192, 6481969152] devid 2, profile raid0 |
| ------------[ cut here ]------------ |
| kernel BUG at include/linux/scatterlist.h:115! |
| Oops: invalid opcode: 0000 [#1] PREEMPT SMP PTI |
| CPU: 0 PID: 1012 Comm: btrfs Not tainted 6.10.0-rc7+ #567 |
| RIP: 0010:__blk_rq_map_sg+0x339/0x4a0 |
| RSP: 0018:ffffc90001a43820 EFLAGS: 00010202 |
| RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffea00045d4802 |
| RDX: 0000000117520000 RSI: 0000000000000000 RDI: ffff8881027d1000 |
| RBP: 0000000000003000 R08: ffffea00045d4902 R09: 0000000000000000 |
| R10: 0000000000000000 R11: 0000000000001000 R12: ffff8881003d10b8 |
| R13: ffffc90001a438f0 R14: 0000000000000000 R15: 0000000000003000 |
| FS: 00007fcc048a6900(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 000000002cd11000 CR3: 00000001109ea001 CR4: 0000000000370eb0 |
| Call Trace: |
| <TASK> |
| ? __die_body.cold+0x14/0x25 |
| ? die+0x2e/0x50 |
| ? do_trap+0xca/0x110 |
| ? do_error_trap+0x65/0x80 |
| ? __blk_rq_map_sg+0x339/0x4a0 |
| ? exc_invalid_op+0x50/0x70 |
| ? __blk_rq_map_sg+0x339/0x4a0 |
| ? asm_exc_invalid_op+0x1a/0x20 |
| ? __blk_rq_map_sg+0x339/0x4a0 |
| nvme_prep_rq.part.0+0x9d/0x770 |
| nvme_queue_rq+0x7d/0x1e0 |
| __blk_mq_issue_directly+0x2a/0x90 |
| ? blk_mq_get_budget_and_tag+0x61/0x90 |
| blk_mq_try_issue_list_directly+0x56/0xf0 |
| blk_mq_flush_plug_list.part.0+0x52b/0x5d0 |
| __blk_flush_plug+0xc6/0x110 |
| blk_finish_plug+0x28/0x40 |
| read_pages+0x160/0x1c0 |
| page_cache_ra_unbounded+0x109/0x180 |
| relocate_file_extent_cluster+0x611/0x6a0 |
| ? btrfs_search_slot+0xba4/0xd20 |
| ? balance_dirty_pages_ratelimited_flags+0x26/0xb00 |
| relocate_data_extent.constprop.0+0x134/0x160 |
| relocate_block_group+0x3f2/0x500 |
| btrfs_relocate_block_group+0x250/0x430 |
| btrfs_relocate_chunk+0x3f/0x130 |
| btrfs_balance+0x71b/0xef0 |
| ? kmalloc_trace_noprof+0x13b/0x280 |
| btrfs_ioctl+0x2c2e/0x3030 |
| ? kvfree_call_rcu+0x1e6/0x340 |
| ? list_lru_add_obj+0x66/0x80 |
| ? mntput_no_expire+0x3a/0x220 |
| __x64_sys_ioctl+0x96/0xc0 |
| do_syscall_64+0x54/0x110 |
| entry_SYSCALL_64_after_hwframe+0x76/0x7e |
| RIP: 0033:0x7fcc04514f9b |
| Code: Unable to access opcode bytes at 0x7fcc04514f71. |
| RSP: 002b:00007ffeba923370 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 |
| RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fcc04514f9b |
| RDX: 00007ffeba923460 RSI: 00000000c4009420 RDI: 0000000000000003 |
| RBP: 0000000000000000 R08: 0000000000000013 R09: 0000000000000001 |
| R10: 00007fcc043fbba8 R11: 0000000000000246 R12: 00007ffeba924fc5 |
| R13: 00007ffeba923460 R14: 0000000000000002 R15: 00000000004d4bb0 |
| </TASK> |
| Modules linked in: |
| ---[ end trace 0000000000000000 ]--- |
| RIP: 0010:__blk_rq_map_sg+0x339/0x4a0 |
| RSP: 0018:ffffc90001a43820 EFLAGS: 00010202 |
| RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffea00045d4802 |
| RDX: 0000000117520000 RSI: 0000000000000000 RDI: ffff8881027d1000 |
| RBP: 0000000000003000 R08: ffffea00045d4902 R09: 0000000000000000 |
| R10: 0000000000000000 R11: 0000000000001000 R12: ffff8881003d10b8 |
| R13: ffffc90001a438f0 R14: 0000000000000000 R15: 0000000000003000 |
| FS: 00007fcc048a6900(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 00007fcc04514f71 CR3: 00000001109ea001 CR4: 0000000000370eb0 |
| Kernel panic - not syncing: Fatal exception |
| Kernel Offset: disabled |
| ---[ end Kernel panic - not syncing: Fatal exception ]--- |
| |
| So in case of a relocation on a RAID stripe-tree based file system, skip |
| the readahead. |
| |
| The Linux kernel CVE team has assigned CVE-2024-49932 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 6.11.3 with commit f7a1218a983ab98aba140dc20b25f60b39ee4033 |
| Fixed in 6.12 with commit 04915240e2c3a018e4c7f23418478d27226c8957 |
| |
| 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-2024-49932 |
| 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/btrfs/relocation.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/f7a1218a983ab98aba140dc20b25f60b39ee4033 |
| https://git.kernel.org/stable/c/04915240e2c3a018e4c7f23418478d27226c8957 |
