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bpf, xdp, samples: Fix null pointer dereference in *_user code

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Memset on the pointer right after malloc can cause a NULL pointer
deference if it failed to allocate memory. A simple fix is to
replace malloc()/memset() pair with a simple call to calloc().

Fixes: 0fca931a6f ("samples/bpf: program demonstrating access to xdp_rxq_info")
Signed-off-by: Gaurav Singh <gaurav1086@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
This commit is contained in:
Gaurav Singh 2020-06-12 14:53:27 -04:00 committed by Daniel Borkmann
parent c34a06c56d
commit 6903cdae9f
3 changed files with 7 additions and 21 deletions
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8
samples/bpf/xdp_monitor_user.c
View File

@ -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);

7
samples/bpf/xdp_redirect_cpu_user.c
View File

@ -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);
@ -226,11 +223,11 @@ static struct stats_record *alloc_stats_record(void)
size = sizeof(*rec) + n_cpus * sizeof(struct record);
rec = malloc(size);
memset(rec, 0, size);
if (!rec) {
fprintf(stderr, "Mem alloc error\n");
exit(EXIT_FAIL_MEM);
}
memset(rec, 0, size);
rec->rx_cnt.cpu = alloc_record_per_cpu();
rec->redir_err.cpu = alloc_record_per_cpu();
rec->kthread.cpu = alloc_record_per_cpu();

13
samples/bpf/xdp_rxq_info_user.c
View File

@ -198,11 +198,8 @@ 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);
@ -214,11 +211,8 @@ static struct record *alloc_record_per_rxq(void)
{
unsigned int nr_rxqs = bpf_map__def(rx_queue_index_map)->max_entries;
struct record *array;
size_t size;
size = sizeof(struct record) * nr_rxqs;
array = malloc(size);
memset(array, 0, size);
array = calloc(nr_rxqs, sizeof(struct record));
if (!array) {
fprintf(stderr, "Mem alloc error (nr_rxqs:%u)\n", nr_rxqs);
exit(EXIT_FAIL_MEM);
@ -232,8 +226,7 @@ static struct stats_record *alloc_stats_record(void)
struct stats_record *rec;
int i;
rec = malloc(sizeof(*rec));
memset(rec, 0, sizeof(*rec));
rec = calloc(1, sizeof(struct stats_record));
if (!rec) {
fprintf(stderr, "Mem alloc error\n");
exit(EXIT_FAIL_MEM);