d1a6edecc1
Syzkaller reports the following crash:
RIP: 0010:check_return_code kernel/bpf/verifier.c:10575 [inline]
RIP: 0010:do_check kernel/bpf/verifier.c:12346 [inline]
RIP: 0010:do_check_common+0xb3d2/0xd250 kernel/bpf/verifier.c:14610
With the following reproducer:
bpf$PROG_LOAD_XDP(0x5, &(0x7f00000004c0)={0xd, 0x3, &(0x7f0000000000)=ANY=[@ANYBLOB="1800000000000019000000000000000095"], &(0x7f0000000300)='GPL\x00', 0x0, 0x0, 0x0, 0x0, 0x0, '\x00', 0x0, 0x2b, 0xffffffffffffffff, 0x8, 0x0, 0x0, 0x10, 0x0}, 0x80)
Because we don't enforce expected_attach_type for XDP programs,
we end up in hitting 'if (prog->expected_attach_type == BPF_LSM_CGROUP'
part in check_return_code and follow up with testing
`prog->aux->attach_func_proto->type`, but `prog->aux->attach_func_proto`
is NULL.
Add explicit prog_type check for the "Note, BPF_LSM_CGROUP that
attach ..." condition. Also, don't skip return code check for
LSM/STRUCT_OPS.
The above actually brings an issue with existing selftest which
tries to return EPERM from void inet_csk_clone. Fix the
test (and move called_socket_clone to make sure it's not
incremented in case of an error) and add a new one to explicitly
verify this condition.
Fixes: 69fd337a975c ("bpf: per-cgroup lsm flavor")
Reported-by: syzbot+5cc0730bd4b4d2c5f152@syzkaller.appspotmail.com
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220708175000.2603078-1-sdf@google.com
15 lines
347 B
C
15 lines
347 B
C
// SPDX-License-Identifier: GPL-2.0
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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char _license[] SEC("license") = "GPL";
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SEC("lsm_cgroup/inet_csk_clone")
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int BPF_PROG(nonvoid_socket_clone, struct sock *newsk, const struct request_sock *req)
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{
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/* Can not return any errors from void LSM hooks. */
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return 0;
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}
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