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| author | Weiming Shi <bestswngs@gmail.com> | 2026-06-15 05:19:54 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-06-15 07:30:20 +0300 |
| commit | 0c0a8ed85349dae298712d79cb276acfeb794d82 (patch) | |
| tree | c4c4b7569393d4b34bbb03874326ff99e2a17648 | |
| parent | 1f32c0d619d996b395f36a920f58159949be922a (diff) | |
| download | linux-0c0a8ed85349dae298712d79cb276acfeb794d82.tar.xz | |
bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data()
When the scatterlist ring is full or nearly full, bpf_msg_push_data()
enters a copy fallback path and computes copy + len for the page
allocation size. Since len comes from BPF with arg3_type = ARG_ANYTHING
and both are u32, a crafted len can wrap the sum to a small value,
causing an undersized allocation followed by an out-of-bounds memcpy.
BUG: unable to handle page fault for address: ffffed104089a402
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
Call Trace:
__asan_memcpy (mm/kasan/shadow.c:105)
bpf_msg_push_data (net/core/filter.c:2852 net/core/filter.c:2788)
bpf_prog_9ed8b5711920a7d7+0x2e/0x36
sk_psock_msg_verdict (net/core/skmsg.c:934)
tcp_bpf_sendmsg (net/ipv4/tcp_bpf.c:421 net/ipv4/tcp_bpf.c:584)
__sys_sendto (net/socket.c:2206)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
Add an overflow check before the allocation.
Link: https://lore.kernel.org/all/20260424155913.A19FDC19425@smtp.kernel.org
Fixes: 6fff607e2f14 ("bpf: sk_msg program helper bpf_msg_push_data")
Tested-by: Xiang Mei <xmei5@asu.edu>
Tested-by: Xinyu Ma <mmmxny@gmail.com>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://lore.kernel.org/r/20260615021959.140010-2-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | net/core/filter.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index 57b00c6cc8cc..4b159045881d 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2829,6 +2829,9 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, if (!space || (space == 1 && start != offset)) copy = msg->sg.data[i].length; + if (unlikely(copy + len < copy)) + return -EINVAL; + page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC | __GFP_COMP, get_order(copy + len)); if (unlikely(!page)) |