Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ext4: don't BUG if someone dirty pages without asking ext4 first [un]pin_user_pages_remote is dirtying pages without properly warning the file system in advance. A related race was noted by Jan Kara in 2018[1]; however, more recently instead of it being a very hard-to-hit race, it could be reliably triggered by process_vm_writev(2) which was discovered by Syzbot[2]. This is technically a bug in mm/gup.c, but arguably ext4 is fragile in that if some other kernel subsystem dirty pages without properly notifying the file system using page_mkwrite(), ext4 will BUG, while other file systems will not BUG (although data will still be lost). So instead of crashing with a BUG, issue a warning (since there may be potential data loss) and just mark the page as clean to avoid unprivileged denial of service attacks until the problem can be properly fixed. More discussion and background can be found in the thread starting at [2]. [1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz [2] https://lore.kernel.org/r/Yg0m6IjcNmfaSokM@google.com
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected a42afc5f56f319107e987aa6adf2f65d93d527c7 before 5db60e76edf5680ff1f3a7221036fc44b308f146; affected a42afc5f56f319107e987aa6adf2f65d93d527c7 before d666dfaa571465a19f014534a214c255ea33f301; affected a42afc5f56f319107e987aa6adf2f65d93d527c7 before 0d3a6926f7e8be3c897fa46216ce13b119a9f56a; affected a42afc5f56f319107e987aa6adf2f65d93d527c7 before 5a016c053f426a73752c3b41b60b497b58694d48; affected a42afc5f56f319107e987aa6adf2f65d93d527c7 before 330d0e44fc5a47c27df958ecdd4693a3cb1d8b81; affected a42afc5f56f319107e987aa6adf2f65d93d527c7 before a0856764dc1276ad2dc7891288c2e9246bf11a37; affected a42afc5f56f319107e987aa6adf2f65d93d527c7 before 343117559ef41e992e326f7a92da1a8f254dfa8c; affected a42afc5f56f319107e987aa6adf2f65d93d527c7 before 677c9d30e8487bee6c8e3b034070319d98f6e203; affected a42afc5f56f319107e987aa6adf2f65d93d527c7 before cc5095747edfb054ca2068d01af20be3fcc3634f |
| Linux / Linux | affected 2.6.37; unaffected 0 before 2.6.37; unaffected 4.9.311 through 4.9.*; unaffected 4.14.276 through 4.14.*; unaffected 4.19.238 through 4.19.*; unaffected 5.4.189 through 5.4.*; unaffected 5.10.110 through 5.10.*; unaffected 5.15.33 through 5.15.*; unaffected 5.16.19 through 5.16.*; unaffected 5.17.2 through 5.17.*; unaffected 5.18 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/5db60e76edf5680ff1f3a7221036fc44b308f146
- https://git.kernel.org/stable/c/d666dfaa571465a19f014534a214c255ea33f301
- https://git.kernel.org/stable/c/0d3a6926f7e8be3c897fa46216ce13b119a9f56a
- https://git.kernel.org/stable/c/5a016c053f426a73752c3b41b60b497b58694d48
- https://git.kernel.org/stable/c/330d0e44fc5a47c27df958ecdd4693a3cb1d8b81
- https://git.kernel.org/stable/c/a0856764dc1276ad2dc7891288c2e9246bf11a37
- https://git.kernel.org/stable/c/343117559ef41e992e326f7a92da1a8f254dfa8c
- https://git.kernel.org/stable/c/677c9d30e8487bee6c8e3b034070319d98f6e203
- https://git.kernel.org/stable/c/cc5095747edfb054ca2068d01af20be3fcc3634f