CVE-2023-53186

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