# CVE-2021-47145: linux: In the Linux kernel, the following vulnerability has been resolved:  btrfs: do not BUG_ON in link_to_fixup_dir  While...

CVE-2021-47145 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47145, released March 25, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-47145
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0027
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 25, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  btrfs: do not BUG_ON in link_to_fixup_dir  While doing error injection testing I got the following panic    kernel BUG at fs/btrfs/tree-log.c:1862!   invalid opcode: 0000 [#1] SMP NOPTI   CPU: 1 PID: 7836 Comm: mount Not tainted 5.13.0-rc1+ #305   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014   RIP: 0010:link_to_fixup_dir+0xd5/0xe0   RSP: 0018:ffffb5800180fa30 EFLAGS: 00010216   RAX: fffffffffffffffb RBX: 00000000fffffffb RCX: ffff8f595287faf0   RDX: ffffb5800180fa37 RSI: ffff8f5954978800 RDI: 0000000000000000   RBP: ffff8f5953af9450 R08: 0000000000000019 R09: 0000000000000001   R10: 000151f408682970 R11: 0000000120021001 R12: ffff8f5954978800   R13: ffff8f595287faf0 R14: ffff8f5953c77dd0 R15: 0000000000000065   FS:  00007fc5284c8c40(0000) GS:ffff8f59bbd00000(0000) knlGS:0000000000000000   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033   CR2: 00007fc5287f47c0 CR3: 000000011275e002 CR4: 0000000000370ee0   Call Trace:    replay_one_buffer+0x409/0x470    ? btree_read_extent_buffer_pages+0xd0/0x110    walk_up_log_tree+0x157/0x1e0    walk_log_tree+0xa6/0x1d0    btrfs_recover_log_trees+0x1da/0x360    ? replay_one_extent+0x7b0/0x7b0    open_ctree+0x1486/0x1720    btrfs_mount_root.cold+0x12/0xea    ? __kmalloc_track_caller+0x12f/0x240    legacy_get_tree+0x24/0x40    vfs_get_tree+0x22/0xb0    vfs_kern_mount.part.0+0x71/0xb0    btrfs_mount+0x10d/0x380    ? vfs_parse_fs_string+0x4d/0x90    legacy_get_tree+0x24/0x40    vfs_get_tree+0x22/0xb0    path_mount+0x433/0xa10    __x64_sys_mount+0xe3/0x120    do_syscall_64+0x3d/0x80    entry_SYSCALL_64_after_hwframe+0x44/0xae  We can get -EIO or any number of legitimate errors from btrfs_search_slot(), panicing here is not the appropriate response.  The error path for this code handles errors properly, simply return the error.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.14.6-1 | [DEBIAN-CVE-2021-47145](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47145.md) | Mar 25, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.14.6-1 | [DEBIAN-CVE-2021-47145](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47145.md) | Mar 25, 2024 |
| Linux | linux Debian 14 | 5.14.6-1 | [DEBIAN-CVE-2021-47145](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47145.md) | Mar 25, 2024 |

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