From 9c481b908b011398b1491752271cd1e2c9ad5758 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 14 Feb 2018 15:31:00 +0100 Subject: bpf: fix bpf_prog_array_copy_to_user warning from perf event prog query syzkaller tried to perform a prog query in perf_event_query_prog_array() where struct perf_event_query_bpf had an ids_len of 1,073,741,353 and thus causing a warning due to failed kcalloc() allocation out of the bpf_prog_array_copy_to_user() helper. Given we cannot attach more than 64 programs to a perf event, there's no point in allowing huge ids_len. Therefore, allow a buffer that would fix the maximum number of ids and also add a __GFP_NOWARN to the temporary ids buffer. Fixes: f371b304f12e ("bpf/tracing: allow user space to query prog array on the same tp") Fixes: 0911287ce32b ("bpf: fix bpf_prog_array_copy_to_user() issues") Reported-by: syzbot+cab5816b0edbabf598b3@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov --- kernel/trace/bpf_trace.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/trace/bpf_trace.c') diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index fc2838ac8b78..c0a9e310d715 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -872,6 +872,8 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info) return -EINVAL; if (copy_from_user(&query, uquery, sizeof(query))) return -EFAULT; + if (query.ids_len > BPF_TRACE_MAX_PROGS) + return -E2BIG; mutex_lock(&bpf_event_mutex); ret = bpf_prog_array_copy_info(event->tp_event->prog_array, -- cgit v1.2.3