cbcvebase.
CVE-2024-36001
published 2024-05-20

CVE-2024-36001: In the Linux kernel, the following vulnerability has been resolved: netfs: Fix the pre-flush when appending to a file in writethrough mode In…

PriorityP338high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.20%
10.6th percentile
In the Linux kernel, the following vulnerability has been resolved: netfs: Fix the pre-flush when appending to a file in writethrough mode In netfs_perform_write(), when the file is marked NETFS_ICTX_WRITETHROUGH or O_*SYNC or RWF_*SYNC was specified, write-through caching is performed on a buffered file. When setting up for write-through, we flush any conflicting writes in the region and wait for the write to complete, failing if there's a write error to return. The issue arises if we're writing at or above the EOF position because we skip the flush and - more importantly - the wait. This becomes a problem if there's a partial folio at the end of the file that is being written out and we want to make a write to it too. Both the already-running write and the write we start both want to clear the writeback mark, but whoever is second causes a warning looking something like: ------------[ cut here ]------------ R=00000012: folio 11 is not under writeback WARNING: CPU: 34 PID: 654 at fs/netfs/write_collect.c:105 ... CPU: 34 PID: 654 Comm: kworker/u386:27 Tainted: G S ... ... Workqueue: events_unbound netfs_write_collection_worker ... RIP: 0010:netfs_writeback_lookup_folio Fix this by making the flush-and-wait unconditional. It will do nothing if there are no folios in the pagecache and will return quickly if there are no folios in the region specified. Further, move the WBC attachment above the flush call as the flush is going to attach a WBC and detach it again if it is not present - and since we need one anyway we might as well share it.

Affected

9 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.8.9-1 (forky)linux 6.8.9-1 (forky)
linuxlinux
linuxlinux>= 41d8e7673a7726cba57cb8112d81c89cfb6c3e35 < 5eaf23b2e81349f6614f88396dc468fda89fc0b95eaf23b2e81349f6614f88396dc468fda89fc0b9
linuxlinux>= 41d8e7673a7726cba57cb8112d81c89cfb6c3e35 < c97f59e276d4e93480f29a70accbd0d7273cf3f5c97f59e276d4e93480f29a70accbd0d7273cf3f5
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.8.9-16.8.9-1
linuxlinux_kernel>= 0 < 6.8.9-16.8.9-1
linuxlinux_kernel>= 0 < 6.8.0-40.406.8.0-40.40
linuxlinux_kernel>= 6.8 < 6.8.96.8.9

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8LOW
vendor_redhat7.8HIGH
vendor_ubuntu6.5MEDIUM
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