From: Jiayuan Chen <[email protected]> Date: Fri, 12 Jun 2026 21:07:46 +0800 > From: Weiming Shi <[email protected]> > > When bpf_msg_push_data() splits a scatterlist element into head and > tail, the tail's page offset is advanced by `start` (absolute message > byte offset) instead of `start - offset` (byte position within the > element). This makes rsge.offset overshoot by `offset` bytes, pointing > to the wrong location within the page or beyond its boundary. Consumers > of the corrupted entry either silently read wrong data or trigger an > out-of-bounds access. > > BUG: KASAN: slab-use-after-free in bpf_msg_pull_data (net/core/filter.c:2728) > Read of size 32752 at addr ffff8881042f0010 by task poc/130 > Call Trace: > __asan_memcpy (mm/kasan/shadow.c:105) > bpf_msg_pull_data (net/core/filter.c:2728) > bpf_prog_run_pin_on_cpu (include/linux/bpf.h:1402) > sk_psock_msg_verdict (net/core/skmsg.c:934) > tcp_bpf_send_verdict (net/ipv4/tcp_bpf.c:421) > sock_sendmsg_nosec (net/socket.c:727) > > Fixes: 6fff607e2f14 ("bpf: sk_msg program helper bpf_msg_push_data") > Reported-by: Xiang Mei <[email protected]> > Reviewed-by: Jiayuan Chen <[email protected]> > Reviewed-by: Emil Tsalapatis <[email protected]> > Signed-off-by: Weiming Shi <[email protected]> > Signed-off-by: Jiayuan Chen <[email protected]>
Reviewed-by: Kuniyuki Iwashima <[email protected]>
