Add str2num() helper and replace atoi() with it. atoi() does not provide
overflow checks, checks of invalid characters in a string and it is
recommended to use strtol-like functions (Cf. atoi() manpage).
Signed-off-by: Mikhail Ivanov <ivanov.mikhail1@xxxxxxxxxxxxxxxxxxx>
---
samples/landlock/sandboxer.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)
diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index e8223c3e781a..d4dba9e4ce89 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c
@@ -150,6 +150,26 @@ static int populate_ruleset_fs(const char *const env_var, const int ruleset_fd,
return ret;
}
+static int str2num(const char *numstr, unsigned long long *num_dst)
+{
+ char *endptr = NULL;
+ int err = 1;
+ unsigned long long num;
+
+ errno = 0;
+ num = strtoull(numstr, &endptr, 0);
+ if (errno != 0)
+ goto out;
+
+ if (*endptr != '\0')
+ goto out;
+
+ *num_dst = num;
+ err = 0;
+out:
+ return err;
+}
+
static int populate_ruleset_net(const char *const env_var, const int ruleset_fd,
const __u64 allowed_access)
{
@@ -168,7 +188,12 @@ static int populate_ruleset_net(const char *const env_var, const int ruleset_fd,
env_port_name_next = env_port_name;
while ((strport = strsep(&env_port_name_next, ENV_DELIMITER))) {
- net_port.port = atoi(strport);
+ if (str2num(strport, &net_port.port)) {
+ fprintf(stderr,
+ "Failed to convert \"%s\" into a number\n",
+ strport);
+ goto out_free_name;
+ }
if (landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_PORT,
&net_port, 0)) {
fprintf(stderr,
--
2.34.1
