From: Breno Leitao leitao@debian.org

[ Upstream commit dd9cef43c222df7c0d76d34451808e789952379d ]

When compiling test_maps selftest with GCC-8, it warns that an array might be indexed with a negative value, which could cause a negative out of bound access, depending on parameters of the function. This is the GCC-8 warning:

gcc -Wall -O2 -I../../../include/uapi -I../../../lib -I../../../lib/bpf -I../../../../include/generated -DHAVE_GENHDR -I../../../include test_maps.c /home/breno/Devel/linux/tools/testing/selftests/bpf/libbpf.a -lcap -lelf -lrt -lpthread -o /home/breno/Devel/linux/tools/testing/selftests/bpf/test_maps In file included from test_maps.c:16: test_maps.c: In function ‘run_all_tests’: test_maps.c:1079:10: warning: array subscript -1 is below array bounds of ‘pid_t[<Ube20> + 1]’ [-Warray-bounds] assert(waitpid(pid[i], &status, 0) == pid[i]); ^~~~~~~~~~~~~~~~~~~~~~~~~~~ test_maps.c:1059:6: warning: array subscript -1 is below array bounds of ‘pid_t[<Ube20> + 1]’ [-Warray-bounds] pid[i] = fork(); ~~~^~~

This patch simply guarantees that the task(s) variables are unsigned, thus, they could never be a negative number (which they are not in current code anyway), hence avoiding an out of bound access warning.

Signed-off-by: Breno Leitao leitao@debian.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Sasha Levin sashal@kernel.org --- tools/testing/selftests/bpf/test_maps.c | 27 +++++++++++++------------ 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c index e2b9eee37187..6e05a22b346c 100644 --- a/tools/testing/selftests/bpf/test_maps.c +++ b/tools/testing/selftests/bpf/test_maps.c @@ -43,7 +43,7 @@ static int map_flags; } \ })

-static void test_hashmap(int task, void *data) +static void test_hashmap(unsigned int task, void *data) { long long key, next_key, first_key, value; int fd; @@ -133,7 +133,7 @@ static void test_hashmap(int task, void *data) close(fd); }

-static void test_hashmap_sizes(int task, void *data) +static void test_hashmap_sizes(unsigned int task, void *data) { int fd, i, j;

@@ -153,7 +153,7 @@ static void test_hashmap_sizes(int task, void *data) } }

-static void test_hashmap_percpu(int task, void *data) +static void test_hashmap_percpu(unsigned int task, void *data) { unsigned int nr_cpus = bpf_num_possible_cpus(); BPF_DECLARE_PERCPU(long, value); @@ -280,7 +280,7 @@ static int helper_fill_hashmap(int max_entries) return fd; }

-static void test_hashmap_walk(int task, void *data) +static void test_hashmap_walk(unsigned int task, void *data) { int fd, i, max_entries = 1000; long long key, value, next_key; @@ -351,7 +351,7 @@ static void test_hashmap_zero_seed(void) close(second); }

-static void test_arraymap(int task, void *data) +static void test_arraymap(unsigned int task, void *data) { int key, next_key, fd; long long value; @@ -406,7 +406,7 @@ static void test_arraymap(int task, void *data) close(fd); }

-static void test_arraymap_percpu(int task, void *data) +static void test_arraymap_percpu(unsigned int task, void *data) { unsigned int nr_cpus = bpf_num_possible_cpus(); BPF_DECLARE_PERCPU(long, values); @@ -502,7 +502,7 @@ static void test_arraymap_percpu_many_keys(void) close(fd); }

-static void test_devmap(int task, void *data) +static void test_devmap(unsigned int task, void *data) { int fd; __u32 key, value; @@ -517,7 +517,7 @@ static void test_devmap(int task, void *data) close(fd); }

-static void test_queuemap(int task, void *data) +static void test_queuemap(unsigned int task, void *data) { const int MAP_SIZE = 32; __u32 vals[MAP_SIZE + MAP_SIZE/2], val; @@ -575,7 +575,7 @@ static void test_queuemap(int task, void *data) close(fd); }

-static void test_stackmap(int task, void *data) +static void test_stackmap(unsigned int task, void *data) { const int MAP_SIZE = 32; __u32 vals[MAP_SIZE + MAP_SIZE/2], val; @@ -641,7 +641,7 @@ static void test_stackmap(int task, void *data) #define SOCKMAP_PARSE_PROG "./sockmap_parse_prog.o" #define SOCKMAP_VERDICT_PROG "./sockmap_verdict_prog.o" #define SOCKMAP_TCP_MSG_PROG "./sockmap_tcp_msg_prog.o" -static void test_sockmap(int tasks, void *data) +static void test_sockmap(unsigned int tasks, void *data) { struct bpf_map *bpf_map_rx, *bpf_map_tx, *bpf_map_msg, *bpf_map_break; int map_fd_msg = 0, map_fd_rx = 0, map_fd_tx = 0, map_fd_break; @@ -1258,10 +1258,11 @@ static void test_map_large(void) }

#define run_parallel(N, FN, DATA) \ - printf("Fork %d tasks to '" #FN "'\n", N); \ + printf("Fork %u tasks to '" #FN "'\n", N); \ __run_parallel(N, FN, DATA)

-static void __run_parallel(int tasks, void (*fn)(int task, void *data), +static void __run_parallel(unsigned int tasks, + void (*fn)(unsigned int task, void *data), void *data) { pid_t pid[tasks]; @@ -1302,7 +1303,7 @@ static void test_map_stress(void) #define DO_UPDATE 1 #define DO_DELETE 0

-static void test_update_delete(int fn, void *data) +static void test_update_delete(unsigned int fn, void *data) { int do_update = ((int *)data)[1]; int fd = ((int *)data)[0];