CVE-2023-53186

Description

In the Linux kernel, the following vulnerability has been resolved: skbuff: Fix a race between coalescing and releasing SKBs Commit 1effe8ca4e34 ("skbuff: fix coalescing for page_pool fragment recycling") allowed coalescing to proceed with non page pool page and page pool page when @from is cloned, i.e. to->pp_recycle --> false from->pp_recycle --> true skb_cloned(from) --> true However, it actually requires skb_cloned(@from) to hold true until coalescing finishes in this situation. If the other cloned SKB is released while the merging is in process, from_shinfo->nr_frags will be set to 0 toward the end of the function, causing the increment of frag page _refcount to be unexpectedly skipped resulting in inconsistent reference counts. Later when SKB(@to) is released, it frees the page directly even though the page pool page is still in use, leading to use-after-free or double-free errors. So it should be prohibited. The double-free error message below prompted us to investigate: BUG: Bad page state in process swapper/1 pfn:0e0d1 page:00000000c6548b28 refcount:-1 mapcount:0 mapping:0000000000000000 index:0x2 pfn:0xe0d1 flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff) raw: 000fffffc0000000 0000000000000000 ffffffff00000101 0000000000000000 raw: 0000000000000002 0000000000000000 ffffffffffffffff 0000000000000000 page dumped because: nonzero _refcount CPU: 1 PID: 0 Comm: swapper/1 Tainted: G E 6.2.0+ Call Trace: <IRQ> dump_stack_lvl+0x32/0x50 bad_page+0x69/0xf0 free_pcp_prepare+0x260/0x2f0 free_unref_page+0x20/0x1c0 skb_release_data+0x10b/0x1a0 napi_consume_skb+0x56/0x150 net_rx_action+0xf0/0x350 ? __napi_schedule+0x79/0x90 __do_softirq+0xc8/0x2b1 __irq_exit_rcu+0xb9/0xf0 common_interrupt+0x82/0xa0 </IRQ> <TASK> asm_common_interrupt+0x22/0x40 RIP: 0010:default_idle+0xb/0x20

CVSS Metrics

• v3.1•MEDIUM•Score: 4.7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.02%• Percentile: 4%

Techniques & Countermeasures

• CWE-362•Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

  The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Affected Systems

• linux•linux

  ≥ 53e0961da1c7bbdabd1abebb20de403ec237ec09, < 906a6689bb0191ad2a44131a3377006aa098af59 | ≥ 53e0961da1c7bbdabd1abebb20de403ec237ec09, < 71850b5af92da21b4862a9bc55bda61091247d00 | ≥ 53e0961da1c7bbdabd1abebb20de403ec237ec09, < 5f692c992a3bb9a8018e3488098b401a4229e7ec | ≥ 53e0961da1c7bbdabd1abebb20de403ec237ec09, < 0646dc31ca886693274df5749cd0c8c1eaaeb5ca | 5.15

• linux•linux_kernel

  ≥ 5.15, < 5.15.108 | ≥ 5.16, < 6.1.25 | ≥ 6.2, < 6.2.12 | 6.3:rc1 | 6.3:rc2 | 6.3:rc3 | 6.3:rc4 | 6.3:rc5 | 6.3:rc6

References (4)

• https://git.kernel.org/stable/c/906a6689bb0191ad2a44131a3377006aa098af59
• https://git.kernel.org/stable/c/71850b5af92da21b4862a9bc55bda61091247d00
• https://git.kernel.org/stable/c/5f692c992a3bb9a8018e3488098b401a4229e7ec
• https://git.kernel.org/stable/c/0646dc31ca886693274df5749cd0c8c1eaaeb5ca