Updated: 2024-08-13 01:41:55.336103
Description:
In the Linux kernel, the following vulnerability has been resolved: ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find() Syzbot reports a warning as follows: ============================================ WARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290 Modules linked in: CPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7 RIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419 Call Trace: <TASK> ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375 generic_shutdown_super+0x136/0x2d0 fs/super.c:641 kill_block_super+0x44/0x90 fs/super.c:1675 ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327 [...] ============================================ This is because when finding an entry in ext4_xattr_block_cache_find(), if ext4_sb_bread() returns -ENOMEM, the ce's e_refcnt, which has already grown in the __entry_find(), won't be put away, and eventually trigger the above issue in mb_cache_destroy() due to reference count leakage. So call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix.
| Links | NIST | CIRCL | RHEL | Ubuntu |
| Severity | Score | |
|---|---|---|
| CVSS Version 2.x | NONE | 0 |
| CVSS Version 3.x | MEDIUM | 5.5 |
| OS name | Project name | Version | Score | Severity | Status | Errata | Last updated |
|---|---|---|---|---|---|---|---|
| AlmaLinux 9.2 ESU | kernel | 5.14.0 | 5.5 | MEDIUM | Ignored | 2024-08-13 14:24:42 | |
| AlmaLinux 9.2 FIPS | kernel | 5.14.0 | 5.5 | MEDIUM | Ignored | 2024-08-13 14:24:42 | |
| CentOS 6 ELS | kernel | 2.6.32 | 5.5 | MEDIUM | Ignored | 2024-08-13 14:24:42 | |
| CentOS 7 ELS | kernel | 3.10.0 | 5.5 | MEDIUM | Ignored | 2024-08-13 14:24:41 | |
| CentOS 8.4 ELS | kernel | 4.18.0 | 5.5 | MEDIUM | Ignored | 2024-08-20 05:25:41 | |
| CentOS 8.5 ELS | kernel | 4.18.0 | 5.5 | MEDIUM | Ignored | 2024-08-20 05:25:42 | |
| CentOS Stream 8 ELS | kernel | 4.18.0 | 5.5 | MEDIUM | Ignored | 2024-08-20 05:25:41 | |
| CloudLinux 6 ELS | kernel | 2.6.32 | 5.5 | MEDIUM | Ignored | 2024-08-13 14:24:42 | |
| CloudLinux 7 ELS | kernel | 3.10.0 | 5.5 | MEDIUM | Ignored | 2024-08-13 14:24:41 | |
| Oracle Linux 6 ELS | kernel | 2.6.32 | 5.5 | MEDIUM | Ignored | 2024-08-13 14:24:41 |