[PATCH] [bpf] xdp_monitor_user: Fix null pointer dereference

[Gaurav Singh]

Memset() on the pointer right after malloc() can cause
a null pointer dereference if it failed to allocate memory.
Fix this by replacing malloc/memset with a single calloc().

Signed-off-by: Gaurav Singh <gaurav1...@gmail.com>
---
 samples/bpf/xdp_monitor_user.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/samples/bpf/xdp_monitor_user.c b/samples/bpf/xdp_monitor_user.c
index dd558cbb2309..ef53b93db573 100644
--- a/samples/bpf/xdp_monitor_user.c
+++ b/samples/bpf/xdp_monitor_user.c
@@ -509,11 +509,8 @@ static void *alloc_rec_per_cpu(int record_size)
 {
        unsigned int nr_cpus = bpf_num_possible_cpus();
        void *array;
-       size_t size;
 
-       size = record_size * nr_cpus;
-       array = malloc(size);
-       memset(array, 0, size);
+       array = calloc(nr_cpus, record_size);
        if (!array) {
                fprintf(stderr, "Mem alloc error (nr_cpus:%u)\n", nr_cpus);
                exit(EXIT_FAIL_MEM);
@@ -528,8 +525,7 @@ static struct stats_record *alloc_stats_record(void)
        int i;
 
        /* Alloc main stats_record structure */
-       rec = malloc(sizeof(*rec));
-       memset(rec, 0, sizeof(*rec));
+       rec = calloc(1, sizeof(*rec));
        if (!rec) {
                fprintf(stderr, "Mem alloc error\n");
                exit(EXIT_FAIL_MEM);
-- 
2.17.1