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.
Metrics
Affected Vendors & Products
References
History
Thu, 09 Jan 2025 15:45:00 +0000
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Tue, 07 Jan 2025 23:30:00 +0000
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First Time appeared |
Linux
Linux linux Kernel |
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Weaknesses | CWE-416 | |
CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.13:rc4:*:*:*:*:*:* |
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Vendors & Products |
Linux
Linux linux Kernel |
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Metrics |
cvssV3_1
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cvssV3_1
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Tue, 07 Jan 2025 01:30:00 +0000
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References |
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Metrics |
threat_severity
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cvssV3_1
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Mon, 06 Jan 2025 16:30:00 +0000
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Description | 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. | |
Title | btrfs: fix use-after-free when COWing tree bock and tracing is enabled | |
References |
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2025-01-06T16:20:39.668Z
Updated: 2025-01-09T15:35:56.726Z
Reserved: 2024-12-29T11:26:39.761Z
Link: CVE-2024-56759
Vulnrichment
No data.
NVD
Status : Modified
Published: 2025-01-06T17:15:40.900
Modified: 2025-01-09T16:16:23.547
Link: CVE-2024-56759
Redhat