[PATCH] [bpf] xdp_redirect_cpu_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_redirect_cpu_user.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/samples/bpf/xdp_redirect_cpu_user.c 
b/samples/bpf/xdp_redirect_cpu_user.c
index f3468168982e..2ae7a9a1d950 100644
--- a/samples/bpf/xdp_redirect_cpu_user.c
+++ b/samples/bpf/xdp_redirect_cpu_user.c
@@ -207,11 +207,8 @@ static struct datarec *alloc_record_per_cpu(void)
 {
        unsigned int nr_cpus = bpf_num_possible_cpus();
        struct datarec *array;
-       size_t size;
 
-       size = sizeof(struct datarec) * nr_cpus;
-       array = malloc(size);
-       memset(array, 0, size);
+       array = calloc(nr_cpus, sizeof(struct datarec));
        if (!array) {
                fprintf(stderr, "Mem alloc error (nr_cpus:%u)\n", nr_cpus);
                exit(EXIT_FAIL_MEM);
@@ -222,11 +219,9 @@ static struct datarec *alloc_record_per_cpu(void)
 static struct stats_record *alloc_stats_record(void)
 {
        struct stats_record *rec;
-       int i, size;
+       int i;
 
-       size = sizeof(*rec) + n_cpus * sizeof(struct record);
-       rec = malloc(size);
-       memset(rec, 0, size);
+       rec = calloc(n_cpus + 1, sizeof(struct record));
        if (!rec) {
                fprintf(stderr, "Mem alloc error\n");
                exit(EXIT_FAIL_MEM);
-- 
2.17.1