In the Linux kernel, the following vulnerability has been resolved: net/x25: Fix potential double free of skb When alloc_skb fails in x25_queue_rx_frame it calls kfree_skb(skb) at line 48 and returns 1 (error). This error propagates back through the call chain: x25_queue_rx_frame returns 1 | v x25_state3_machine receives the return value 1 and takes the else branch at line 278, setting queued=0 and returning 0 | v x25_process_rx_frame returns queued=0 | v x25_backlog_rcv at line 452 sees queued=0 and calls kfree_skb(skb) again This would free the same skb twice. Looking at x25_backlog_rcv: net/x25/x25_in.c:x25_backlog_rcv() { ... queued = x25_process_rx_frame(sk, skb); ... if (!queued) kfree_skb(skb); }
https://git.kernel.org/stable/c/fa1dbc93530b34fab0da9862426fe9c918c74dc0
https://git.kernel.org/stable/c/f782dd382203b2a8c4552a628431b7de65a19a7b
https://git.kernel.org/stable/c/d10a26aa4d072320530e6968ef945c8c575edf61
https://git.kernel.org/stable/c/c87dd137c0dad07cc55f98181ff380b0c23d2878
https://git.kernel.org/stable/c/5d0aa038a90b30c9bedde0c41c1fdcd98ecb16e9
https://git.kernel.org/stable/c/524371398d8463ea7e101fce2cbf3915645d1730
https://git.kernel.org/stable/c/3f5e3005984645bf5bd129c6b13149879580b1fb
https://git.kernel.org/stable/c/143d4fa68ae9efb83b0c55b12cc7f0d03732a2b1