From: Eduard Zingerman eddyz87@gmail.com
[ Upstream commit b23ed4d74c4d583b5f621ee4c776699442833554 ]
Dan Carpenter reported invalid check for calloc() result in test_verifier.c:get_xlated_program():
./tools/testing/selftests/bpf/test_verifier.c:1365 get_xlated_program() warn: variable dereferenced before check 'buf' (see line 1364)
./tools/testing/selftests/bpf/test_verifier.c 1363 *cnt = xlated_prog_len / buf_element_size; 1364 *buf = calloc(*cnt, buf_element_size); 1365 if (!buf) {
This should be if (!*buf) {
1366 perror("can't allocate xlated program buffer"); 1367 return -ENOMEM;
This commit refactors the get_xlated_program() to avoid using double pointer type.
Fixes: 933ff53191eb ("selftests/bpf: specify expected instructions in test_verifier tests") Reported-by: Dan Carpenter dan.carpenter@linaro.org Signed-off-by: Eduard Zingerman eddyz87@gmail.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Closes: https://lore.kernel.org/bpf/ZH7u0hEGVB4MjGZq@moroto/ Link: https://lore.kernel.org/bpf/20230609221637.2631800-1-eddyz87@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/testing/selftests/bpf/test_verifier.c | 24 +++++++++++---------- 1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index e4657c5bc3f12..4683ff84044d6 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -1227,45 +1227,46 @@ static bool cmp_str_seq(const char *log, const char *exp) return true; }
-static int get_xlated_program(int fd_prog, struct bpf_insn **buf, int *cnt) +static struct bpf_insn *get_xlated_program(int fd_prog, int *cnt) { + __u32 buf_element_size = sizeof(struct bpf_insn); struct bpf_prog_info info = {}; __u32 info_len = sizeof(info); __u32 xlated_prog_len; - __u32 buf_element_size = sizeof(struct bpf_insn); + struct bpf_insn *buf;
if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) { perror("bpf_prog_get_info_by_fd failed"); - return -1; + return NULL; }
xlated_prog_len = info.xlated_prog_len; if (xlated_prog_len % buf_element_size) { printf("Program length %d is not multiple of %d\n", xlated_prog_len, buf_element_size); - return -1; + return NULL; }
*cnt = xlated_prog_len / buf_element_size; - *buf = calloc(*cnt, buf_element_size); + buf = calloc(*cnt, buf_element_size); if (!buf) { perror("can't allocate xlated program buffer"); - return -ENOMEM; + return NULL; }
bzero(&info, sizeof(info)); info.xlated_prog_len = xlated_prog_len; - info.xlated_prog_insns = (__u64)(unsigned long)*buf; + info.xlated_prog_insns = (__u64)(unsigned long)buf; if (bpf_prog_get_info_by_fd(fd_prog, &info, &info_len)) { perror("second bpf_prog_get_info_by_fd failed"); goto out_free_buf; }
- return 0; + return buf;
out_free_buf: - free(*buf); - return -1; + free(buf); + return NULL; }
static bool is_null_insn(struct bpf_insn *insn) @@ -1398,7 +1399,8 @@ static bool check_xlated_program(struct bpf_test *test, int fd_prog) if (!check_expected && !check_unexpected) goto out;
- if (get_xlated_program(fd_prog, &buf, &cnt)) { + buf = get_xlated_program(fd_prog, &cnt); + if (!buf) { printf("FAIL: can't get xlated program\n"); result = false; goto out;