From a754de3ccd937500940c6fcd0ad043855f56862d Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Thu, 24 Aug 2017 11:46:32 +0200 Subject: [PATCH] tc/q_netem: Don't dereference possibly NULL pointer Assuming 'opt' might be NULL, move the call to RTA_PAYLOAD to after the check since it dereferences its parameter. Signed-off-by: Phil Sutter --- tc/q_netem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tc/q_netem.c b/tc/q_netem.c index 0975ae11..5a9e7474 100644 --- a/tc/q_netem.c +++ b/tc/q_netem.c @@ -538,7 +538,7 @@ static int netem_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt) int *ecn = NULL; struct tc_netem_qopt qopt; const struct tc_netem_rate *rate = NULL; - int len = RTA_PAYLOAD(opt) - sizeof(qopt); + int len; __u64 rate64 = 0; SPRINT_BUF(b1); @@ -546,6 +546,7 @@ static int netem_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt) if (opt == NULL) return 0; + len = RTA_PAYLOAD(opt) - sizeof(qopt); if (len < 0) { fprintf(stderr, "options size error\n"); return -1;