In the Linux kernel, the following vulnerability has been resolved:
ext4: fix racy may inline data check in dio write
syzbot reports that the following warning from ext4_iomap_begin()
triggers as of the commit referenced below:
if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
return -ERANGE;
This occurs during a dio write, which is never expected to encounter
an inode with inline data. To enforce this behavior,
ext4_dio_write_iter() checks the current inline state of the inode
and clears the MAY_INLINE_DATA state flag to either fall back to
buffered writes, or enforce that any other writers in progress on
the inode are not allowed to create inline data.
The problem is that the check for existing inline data and the state
flag can span a lock cycle. For example, if the ilock is originally
locked shared and subsequently upgraded to exclusive, another writer
may have reacquired the lock and created inline data before the dio
write task acquires the lock and proceeds.
The commit referenced below loosens the lock requirements to allow
some forms of unaligned dio writes to occur under shared lock, but
AFAICT the inline data check was technically already racy for any
dio write that would have involved a lock cycle. Regardless, lift
clearing of the state bit to the same lock critical section that
checks for preexisting inline data on the inode to close the race.
Metrics
Affected Vendors & Products
References
History
Mon, 04 Nov 2024 15:15:00 +0000
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-05-21T15:31:03.694Z
Updated: 2024-12-19T08:25:56.852Z
Reserved: 2024-05-21T15:19:24.241Z
Link: CVE-2023-52786
Vulnrichment
Updated: 2024-08-02T23:11:35.517Z
NVD
Status : Awaiting Analysis
Published: 2024-05-21T16:15:17.413
Modified: 2024-11-21T08:40:35.167
Link: CVE-2023-52786
Redhat