4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit c3494801cd1785e2c25f1a5735fa19ddcf9665da ]
Malicious user space may try to force the verifier to use as much cpu time and memory as possible. Hence check for pending signals while verifying the program. Note that suspend of sys_bpf(PROG_LOAD) syscall will lead to EAGAIN, since the kernel has to release the resources used for program verification.
Reported-by: Anatoly Trosinenko anatoly.trosinenko@gmail.com Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Edward Cree ecree@solarflare.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/verifier.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1438b7396cb4..335c00209f74 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2919,6 +2919,9 @@ static int do_check(struct bpf_verifier_env *env) goto process_bpf_exit; }
+ if (signal_pending(current)) + return -EAGAIN; + if (need_resched()) cond_resched();