cbcvebase.
CVE-2025-21643
published 2025-01-19

CVE-2025-21643: In the Linux kernel, the following vulnerability has been resolved: netfs: Fix kernel async DIO Netfslib needs to be able to handle kernel-initiated…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.21%
11.2th percentile
In the Linux kernel, the following vulnerability has been resolved: netfs: Fix kernel async DIO Netfslib needs to be able to handle kernel-initiated asynchronous DIO that is supplied with a bio_vec[] array. Currently, because of the async flag, this gets passed to netfs_extract_user_iter() which throws a warning and fails because it only handles IOVEC and UBUF iterators. This can be triggered through a combination of cifs and a loopback blockdev with something like: mount //my/cifs/share /foo dd if=/dev/zero of=/foo/m0 bs=4K count=1K losetup --sector-size 4096 --direct-io=on /dev/loop2046 /foo/m0 echo hello >/dev/loop2046 This causes the following to appear in syslog: WARNING: CPU: 2 PID: 109 at fs/netfs/iterator.c:50 netfs_extract_user_iter+0x170/0x250 [netfs] and the write to fail. Fix this by removing the check in netfs_unbuffered_write_iter_locked() that causes async kernel DIO writes to be handled as userspace writes. Note that this change relies on the kernel caller maintaining the existence of the bio_vec array (or kvec[] or folio_queue) until the op is complete.

Affected

9 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.12.10-1 (forky)linux 6.12.10-1 (forky)
linuxlinux
linuxlinux>= 153a9961b551101cd38e94e26cd92fbfd198b19b < 9f3a265836844eda30bf34c2584b8011fd4f0f499f3a265836844eda30bf34c2584b8011fd4f0f49
linuxlinux>= 153a9961b551101cd38e94e26cd92fbfd198b19b < 3f6bc9e3ab9b127171d39f9ac6eca1abb693b7313f6bc9e3ab9b127171d39f9ac6eca1abb693b731
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.12.10-16.12.10-1
linuxlinux_kernel>= 0 < 6.12.10-16.12.10-1
linuxlinux_kernel>= 0 < 6.8.0-60.636.8.0-60.63
linuxlinux_kernel>= 6.8 < 6.12.106.12.10

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv7.8HIGH
vendor_ubuntu7.8HIGH
vendor_debian5.5LOW
vendor_redhat5.5MEDIUM
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