UBUNTU-CVE-2023-52447
In the Linux kernel, the following vulnerability has been resolved: bpf: Defer the free of inner map when necessary When updating or deleting an inner map in map array or map htab, the map may still be accessed by non-sleepable program or sleepable program. However bpf_map_fd_put_ptr() decreases the ref-counter of the inner map directly through bpf_map_put(), if the ref-counter is the last one (which is true for most cases), the inner map will be freed by ops->map_free() in a kworker. But for now, most .map_free() callbacks don't use synchronize_rcu() or its variants to wait for the elapse of a RCU grace period, so after the invocation of ops->map_free completes, the bpf program which is accessing the inner map may incur use-after-free problem. Fix the free of inner map by invoking bpf_map_free_deferred() after both one RCU grace period and one tasks trace RCU grace period if the inner map has been removed from the outer map before. The deferment is accomplished by using call_rcu() or call_rcu_tasks_trace() when releasing the last ref-counter of bpf map. The newly-added rcu_head field in bpf_map shares the same storage space with work field to reduce the size of bpf_map.
02 / AFFECTED SOFTWARE
Affected packages
7 explicit affected versions
29 explicit affected versions
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35 explicit affected versions
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37 explicit affected versions
9 explicit affected versions
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4 explicit affected versions
29 explicit affected versions
13 explicit affected versions
49 explicit affected versions
47 explicit affected versions
9 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
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12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
37 explicit affected versions
30 explicit affected versions
46 explicit affected versions
10 explicit affected versions
26 explicit affected versions
1 explicit affected versions
13 explicit affected versions
16 explicit affected versions
49 explicit affected versions
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3 explicit affected versions
2 explicit affected versions
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1 explicit affected versions
12 explicit affected versions
35 explicit affected versions
25 explicit affected versions
21 explicit affected versions
8 explicit affected versions
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5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
9 explicit affected versions
13 explicit affected versions
7 explicit affected versions
41 explicit affected versions
10 explicit affected versions
12 explicit affected versions
12 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
35 explicit affected versions
37 explicit affected versions
14 explicit affected versions
38 explicit affected versions
39 explicit affected versions
9 explicit affected versions
38 explicit affected versions
11 explicit affected versions
46 explicit affected versions
8 explicit affected versions
7 explicit affected versions
20 explicit affected versions
4 explicit affected versions
1 explicit affected versions
1 explicit affected versions
44 explicit affected versions
10 explicit affected versions
43 explicit affected versions
10 explicit affected versions
8 explicit affected versions
14 explicit affected versions
4 explicit affected versions
7 explicit affected versions
1 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: bpf: Defer the free of inner map when necessary When updating or deleting an inner map in map array or map htab, the map may still be accessed by non-sleepable program or sleepable program. However bpf_map_fd_put_ptr() decreases the ref-counter of the inner map directly through bpf_map_put(), if the ref-counter is the last one (which is true for most cases), the inner map will be freed by ops->map_free() in a kworker. But for now, most .map_free() callbacks don't use synchronize_rcu() or its variants to wait for the elapse of a RCU grace period, so after the invocation of ops->map_free completes, the bpf program which is accessing the inner map may incur use-after-free problem. Fix the free of inner map by invoking bpf_map_free_deferred() after both one RCU grace period and one tasks trace RCU grace period if the inner map has been removed from the outer map before. The deferment is accomplished by using call_rcu() or call_rcu_tasks_trace() when releasing the last ref-counter of bpf map. The newly-added rcu_head field in bpf_map shares the same storage space with work field to reduce the size of bpf_map.
05 / REFERENCES
Further evidence
- https://git.kernel.org/stable/c/62fca83303d608ad4fec3f7428c8685680bb01b0
- https://git.kernel.org/stable/c/876673364161da50eed6b472d746ef88242b2368
- https://git.kernel.org/stable/c/bfd9b20c4862f41d4590fde11d70a5eeae53dcc5
- https://git.kernel.org/stable/c/f91cd728b10c51f6d4a39957ccd56d1e802fc8ee
- https://ubuntu.com/security/CVE-2023-52447
- https://ubuntu.com/security/notices/USN-6688-1
- https://ubuntu.com/security/notices/USN-6818-1
- https://ubuntu.com/security/notices/USN-6818-2
- https://ubuntu.com/security/notices/USN-6818-3
- https://ubuntu.com/security/notices/USN-6818-4
- https://ubuntu.com/security/notices/USN-6819-1
- https://ubuntu.com/security/notices/USN-6819-2
- https://ubuntu.com/security/notices/USN-6819-3
- https://ubuntu.com/security/notices/USN-6819-4
- https://ubuntu.com/security/notices/USN-6820-1
- https://ubuntu.com/security/notices/USN-6820-2
- https://ubuntu.com/security/notices/USN-6821-1
- https://ubuntu.com/security/notices/USN-6821-2
- https://ubuntu.com/security/notices/USN-6821-3
- https://ubuntu.com/security/notices/USN-6821-4
- https://ubuntu.com/security/notices/USN-6828-1
- https://ubuntu.com/security/notices/USN-6871-1
- https://ubuntu.com/security/notices/USN-6892-1
- https://ubuntu.com/security/notices/USN-6919-1
- https://www.cve.org/CVERecord?id=CVE-2023-52447