pam: Fix "buffer overflow" in pam ZTS tests on F38

The pam ZTS tests were reporting a buffer overflow on F38, possibly
due to F38 now setting _FORTIFY_SOURCE=3 by default.  gdb and
valgrind narrowed this down to a snprintf() buffer overflow in
zfs_key_config_modify_session_counter().  I'm not clear why this
particular snprintf() was being flagged as an overflow, but when
I replaced it with an asprintf(), the test passed reliably.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #14802 
Closes #14842
This commit is contained in:
Tony Hutter 2023-05-09 17:55:19 -07:00 committed by GitHub
parent 903c3613d4
commit d3db900a4e
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@ -587,16 +587,11 @@ zfs_key_config_modify_session_counter(pam_handle_t *pamh,
errno);
return (-1);
}
size_t runtime_path_len = strlen(runtime_path);
size_t counter_path_len = runtime_path_len + 1 + 10;
char *counter_path = malloc(counter_path_len + 1);
if (!counter_path) {
char *counter_path;
if (asprintf(&counter_path, "%s/%u", runtime_path, config->uid) == -1)
return (-1);
}
counter_path[0] = 0;
strcat(counter_path, runtime_path);
snprintf(counter_path + runtime_path_len, counter_path_len, "/%d",
config->uid);
const int fd = open(counter_path,
O_RDWR | O_CLOEXEC | O_CREAT | O_NOFOLLOW,
S_IRUSR | S_IWUSR);