Commit 198bf1b0 authored Dec 10, 2014 by Alexei Starovoitov Committed by David S. Miller Dec 10, 2014

net: sock: fix access via invalid file descriptor



0day robot reported the following crash:
[   21.233581] BUG: unable to handle kernel NULL pointer dereference at 0000000000000007
[   21.234709] IP: [<ffffffff8156ebda>] sk_attach_bpf+0x39/0xc2

It's due to bpf_prog_get() returning ERR_PTR.
Check it properly.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Fixes: 89aa0758 ("net: sock: allow eBPF programs to be attached to sockets")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent f95b414e

net/core/filter.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1103,8 +1103,8 @@ int sk_attach_bpf(u32 ufd, struct sock *sk)
		return -EPERM;

		prog = bpf_prog_get(ufd);
		if (!prog)
		return -EINVAL;
		if (IS_ERR(prog))
		return PTR_ERR(prog);

		if (prog->aux->prog_type != BPF_PROG_TYPE_SOCKET_FILTER) {
		/* valid fd, but invalid program type */

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