cbcvebase.
CVE-2024-56759
published 2025-01-06

CVE-2024-56759: In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free when COWing tree bock and tracing is enabled When a COWing a tree…

PriorityP340high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.22%
12.0th percentile
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free when COWing tree bock and tracing is enabled When a COWing a tree block, at btrfs_cow_block(), and we have the tracepoint trace_btrfs_cow_block() enabled and preemption is also enabled (CONFIG_PREEMPT=y), we can trigger a use-after-free in the COWed extent buffer while inside the tracepoint code. This is because in some paths that call btrfs_cow_block(), such as btrfs_search_slot(), we are holding the last reference on the extent buffer @buf so btrfs_force_cow_block() drops the last reference on the @buf extent buffer when it calls free_extent_buffer_stale(buf), which schedules the release of the extent buffer with RCU. This means that if we are on a kernel with preemption, the current task may be preempted before calling trace_btrfs_cow_block() and the extent buffer already released by the time trace_btrfs_cow_block() is called, resulting in a use-after-free. Fix this by moving the trace_btrfs_cow_block() from btrfs_cow_block() to btrfs_force_cow_block() before the COWed extent buffer is freed. This also has a side effect of invoking the tracepoint in the tree defrag code, at defrag.c:btrfs_realloc_node(), since btrfs_force_cow_block() is called there, but this is fine and it was actually missing there.

Affected

17 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.124-1 (bookworm)linux 6.1.124-1 (bookworm)
debianlinux-6.1< linux 6.1.124-1 (bookworm)linux 6.1.124-1 (bookworm)
linuxlinux
linuxlinux>= 3083ee2e18b701122a3b841db83448543a87a583 < ba5120a2fb5f23b4d39d302e181aa5d4e28a90d1ba5120a2fb5f23b4d39d302e181aa5d4e28a90d1
linuxlinux>= 3083ee2e18b701122a3b841db83448543a87a583 < 526ff5b27f090fb15040471f892cd2c9899ce314526ff5b27f090fb15040471f892cd2c9899ce314
linuxlinux>= 3083ee2e18b701122a3b841db83448543a87a583 < 66376f1a73cba57fd0af2631d7888605b738e49966376f1a73cba57fd0af2631d7888605b738e499
linuxlinux>= 3083ee2e18b701122a3b841db83448543a87a583 < 9a466b8693b9add05de99af00c7bdff8259ecf199a466b8693b9add05de99af00c7bdff8259ecf19
linuxlinux>= 3083ee2e18b701122a3b841db83448543a87a583 < c3a403d8ce36f5a809a492581de5ad17843e4701c3a403d8ce36f5a809a492581de5ad17843e4701
linuxlinux>= 3083ee2e18b701122a3b841db83448543a87a583 < 44f52bbe96dfdbe4aca3818a2534520082a0704044f52bbe96dfdbe4aca3818a2534520082a07040
linuxlinux_kernel< 6.12.86.12.8
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.234-15.10.234-1
linuxlinux_kernel>= 0 < 6.1.124-16.1.124-1
linuxlinux_kernel>= 0 < 6.12.8-16.12.8-1
linuxlinux_kernel>= 0 < 6.12.8-16.12.8-1
linuxlinux_kernel>= 0 < 5.15.0-135.1465.15.0-135.146
linuxlinux_kernel>= 0 < 6.8.0-60.636.8.0-60.63

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_debian7.8HIGH
vendor_redhat7.8HIGH
vendor_ubuntu7.8HIGH
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