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authorKumar Kartikeya Dwivedi <memxor@gmail.com>2021-08-21 05:49:49 +0530
committerAlexei Starovoitov <ast@kernel.org>2021-08-24 14:48:40 -0700
commit50b796e645a5d217fd9d8648ec594241e6f1dd57 (patch)
tree13a16f17ec1aebbf52f772ca5bf38cf61efa0027 /samples
parentd7af7e497f0308bc97809cc48b58e8e0f13887e1 (diff)
samples: bpf: Fix a couple of warnings
cookie_uid_helper_example.c: In function ‘main’: cookie_uid_helper_example.c:178:69: warning: ‘ -j ACCEPT’ directive writing 10 bytes into a region of size between 8 and 58 [-Wformat-overflow=] 178 | sprintf(rules, "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT", | ^~~~~~~~~~ /home/kkd/src/linux/samples/bpf/cookie_uid_helper_example.c:178:9: note: ‘sprintf’ output between 53 and 103 bytes into a destination of size 100 178 | sprintf(rules, "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT", | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 179 | file); | ~~~~~ Fix by using snprintf and a sufficiently sized buffer. tracex4_user.c:35:15: warning: ‘write’ reading 12 bytes from a region of size 11 [-Wstringop-overread] 35 | key = write(1, "\e[1;1H\e[2J", 12); /* clear screen */ | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ Use size as 11. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210821002010.845777-2-memxor@gmail.com
Diffstat (limited to 'samples')
-rw-r--r--samples/bpf/cookie_uid_helper_example.c11
-rw-r--r--samples/bpf/tracex4_user.c2
2 files changed, 9 insertions, 4 deletions
diff --git a/samples/bpf/cookie_uid_helper_example.c b/samples/bpf/cookie_uid_helper_example.c
index cc3bce8d3aac..54958802c032 100644
--- a/samples/bpf/cookie_uid_helper_example.c
+++ b/samples/bpf/cookie_uid_helper_example.c
@@ -167,7 +167,7 @@ static void prog_load(void)
static void prog_attach_iptables(char *file)
{
int ret;
- char rules[100];
+ char rules[256];
if (bpf_obj_pin(prog_fd, file))
error(1, errno, "bpf_obj_pin");
@@ -175,8 +175,13 @@ static void prog_attach_iptables(char *file)
printf("file path too long: %s\n", file);
exit(1);
}
- sprintf(rules, "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT",
- file);
+ ret = snprintf(rules, sizeof(rules),
+ "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT",
+ file);
+ if (ret < 0 || ret >= sizeof(rules)) {
+ printf("error constructing iptables command\n");
+ exit(1);
+ }
ret = system(rules);
if (ret < 0) {
printf("iptables rule update failed: %d/n", WEXITSTATUS(ret));
diff --git a/samples/bpf/tracex4_user.c b/samples/bpf/tracex4_user.c
index cea399424bca..566e6440e8c2 100644
--- a/samples/bpf/tracex4_user.c
+++ b/samples/bpf/tracex4_user.c
@@ -32,7 +32,7 @@ static void print_old_objects(int fd)
__u64 key, next_key;
struct pair v;
- key = write(1, "\e[1;1H\e[2J", 12); /* clear screen */
+ key = write(1, "\e[1;1H\e[2J", 11); /* clear screen */
key = -1;
while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {