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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2023-52447

bpf: Defer the free of inner map when necessary

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Status
Published
Published
Updated
Assigning organization
Linux

Description

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • bba1dc0b55ac462d24ed1228ad49800c238cd6d7 to < 90c445799fd1dc214d7c6279c144e33a35e29ef2affected
  • bba1dc0b55ac462d24ed1228ad49800c238cd6d7 to < 37d98fb9c3144c0fddf7f6e99aece9927ac8dce6affected
  • bba1dc0b55ac462d24ed1228ad49800c238cd6d7 to < 62fca83303d608ad4fec3f7428c8685680bb01b0affected
  • bba1dc0b55ac462d24ed1228ad49800c238cd6d7 to < f91cd728b10c51f6d4a39957ccd56d1e802fc8eeaffected
  • bba1dc0b55ac462d24ed1228ad49800c238cd6d7 to < bfd9b20c4862f41d4590fde11d70a5eeae53dcc5affected
  • bba1dc0b55ac462d24ed1228ad49800c238cd6d7 to < 876673364161da50eed6b472d746ef88242b2368affected

Linux Linux

Default version status: affected

  • 5.9affected
  • 0 to < 5.9unaffected
  • 5.10.214 to ≤ 5.10.*unaffected
  • 5.15.153 to ≤ 5.15.*unaffected
  • 6.1.75 to ≤ 6.1.*unaffected
  • 6.6.14 to ≤ 6.6.*unaffected
  • 6.7.2 to ≤ 6.7.*unaffected
  • 6.8 to ≤ *unaffected

References