Fix gratuitous use of strdup and x_strdup

There is no need to copy strings passed as arguments to execve,
the only potentially noticeable effect of using strdup/x_strdup
would be a malformed argument list in case of memory allocation error.

Also, x_strdup, being a thin wrapper around strdup, is of no benefit
when its argument is known to be non-NULL, and should not be used in
such cases.

* modules/pam_cracklib/pam_cracklib.c (password_check): Use strdup
instead of x_strdup, the latter is of no benefit in this case.
* modules/pam_ftp/pam_ftp.c (lookup): Likewise.
* modules/pam_userdb/pam_userdb.c (user_lookup): Likewise.
* modules/pam_userdb/pam_userdb.h (x_strdup): Remove.
* modules/pam_mkhomedir/pam_mkhomedir.c (create_homedir): Do not use
x_strdup for strings passed as arguments to execve.
* modules/pam_unix/pam_unix_acct.c (_unix_run_verify_binary): Likewise.
* modules/pam_unix/pam_unix_passwd.c (_unix_run_update_binary): Likewise.
* modules/pam_unix/support.c (_unix_run_helper_binary): Likewise.
(_unix_verify_password): Use strdup instead of x_strdup, the latter
is of no benefit in this case.
* modules/pam_xauth/pam_xauth.c (run_coprocess): Do not use strdup for
strings passed as arguments to execv.

1 files changed, 5 insertions, 7 deletions

diff --git a/modules/pam_xauth/pam_xauth.c b/modules/pam_xauth/pam_xauth.c
index e1c00646..70755475 100644
--- a/modules/pam_xauth/pam_xauth.c
+++ b/modules/pam_xauth/pam_xauth.c
@@ -127,8 +127,7 @@ run_coprocess(pam_handle_t *pamh, const char *input, char **output,
 	if (child == 0) {
 		/* We're the child. */
 		size_t j;
-		char *args[10];
-		const char *tmp;
+		const char *args[10];
 		int maxopened;
 		/* Drop privileges. */
 		if (setgid(gid) == -1)
@@ -166,16 +165,15 @@ run_coprocess(pam_handle_t *pamh, const char *input, char **output,
 		}
 		/* Convert the varargs list into a regular array of strings. */
 		va_start(ap, command);
-		args[0] = strdup(command);
+		args[0] = command;
 		for (j = 1; j < ((sizeof(args) / sizeof(args[0])) - 1); j++) {
-			tmp = va_arg(ap, const char*);
-			if (tmp == NULL) {
+			args[j] = va_arg(ap, const char*);
+			if (args[j] == NULL) {
 				break;
 			}
-			args[j] = strdup(tmp);
 		}
 		/* Run the command. */
-		execv(command, args);
+		execv(command, (char *const *) args);
 		/* Never reached. */
 		_exit(1);
 	}