cbcvebase.
CVE-2024-35798
published 2024-05-17

CVE-2024-35798: In the Linux kernel, the following vulnerability has been resolved: btrfs: fix race in read_extent_buffer_pages() There are reports from tree-checker that…

PriorityP418medium4.7CVSS 3.1
AVLACHPRLUINSUCNINAH
EPSS
0.18%
7.5th percentile
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix race in read_extent_buffer_pages() There are reports from tree-checker that detects corrupted nodes, without any obvious pattern so possibly an overwrite in memory. After some debugging it turns out there's a race when reading an extent buffer the uptodate status can be missed. To prevent concurrent reads for the same extent buffer, read_extent_buffer_pages() performs these checks: /* (1) */ if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags)) return 0; /* (2) */ if (test_and_set_bit(EXTENT_BUFFER_READING, &eb->bflags)) goto done; At this point, it seems safe to start the actual read operation. Once that completes, end_bbio_meta_read() does /* (3) */ set_extent_buffer_uptodate(eb); /* (4) */ clear_bit(EXTENT_BUFFER_READING, &eb->bflags); Normally, this is enough to ensure only one read happens, and all other callers wait for it to finish before returning. Unfortunately, there is a racey interleaving: Thread A | Thread B | Thread C ---------+----------+--------- (1) | | | (1) | (2) | | (3) | | (4) | | | (2) | | | (1) When this happens, thread B kicks of an unnecessary read. Worse, thread C will see UPTODATE set and return immediately, while the read from thread B is still in progress. This race could result in tree-checker errors like this as the extent buffer is concurrently modified: BTRFS critical (device dm-0): corrupted node, root=256 block=8550954455682405139 owner mismatch, have 11858205567642294356 expect [256, 18446744073709551360] Fix it by testing UPTODATE again after setting the READING bit, and if it's been set, skip the unnecessary read. [ minor update of changelog ]

Affected

13 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.7.12-1 (forky)linux 6.7.12-1 (forky)
linuxlinux
linuxlinux>= d7172f52e9933b6ec9305e7fe6e829e3939dba04 < 0427c8ef8bbb7f304de42ef51d69c960e165e0520427c8ef8bbb7f304de42ef51d69c960e165e052
linuxlinux>= d7172f52e9933b6ec9305e7fe6e829e3939dba04 < 3a25878a3378adce5d846300c9570f15aa7f7a803a25878a3378adce5d846300c9570f15aa7f7a80
linuxlinux>= d7172f52e9933b6ec9305e7fe6e829e3939dba04 < 2885d54af2c2e1d910e20d5c8045bae40e02fbc12885d54af2c2e1d910e20d5c8045bae40e02fbc1
linuxlinux>= d7172f52e9933b6ec9305e7fe6e829e3939dba04 < ef1e68236b9153c27cb7cf29ead0c532870d4215ef1e68236b9153c27cb7cf29ead0c532870d4215
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.7.12-16.7.12-1
linuxlinux_kernel>= 0 < 6.7.12-16.7.12-1
linuxlinux_kernel>= 0 < 6.8.0-35.356.8.0-35.35
linuxlinux_kernel>= 6.5 < 6.6.246.6.24
linuxlinux_kernel>= 6.7 < 6.7.126.7.12
linuxlinux_kernel>= 6.8 < 6.8.36.8.3

CVSS provenance

nvdv3.14.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_ubuntu6.3MEDIUM
vendor_debian4.7LOW
vendor_redhat4.7MEDIUM
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