From ec0e724fe53188c5c762c34ca9db6681c0de01b8 Mon Sep 17 00:00:00 2001 From: Iker Pedrosa Date: Thu, 1 Jul 2021 12:14:29 +0200 Subject: [PATCH] pam_filter: Close file after controlling tty Failing to check the descriptor value meant that there was a bug in the attempt to close the controlling tty. Moreover, this would lead to a file descriptor leak as pointed out by the static analyzer tool: Error: RESOURCE_LEAK (CWE-772): [#def26] Linux-PAM-1.5.1/modules/pam_filter/pam_filter.c:356: open_fn: Returning handle opened by "open". [Note: The source code implementation of the function has been overridden by a user model.] Linux-PAM-1.5.1/modules/pam_filter/pam_filter.c:356: var_assign: Assigning: "t" = handle returned from "open("/dev/tty", 2)". Linux-PAM-1.5.1/modules/pam_filter/pam_filter.c:357: off_by_one: Testing whether handle "t" is strictly greater than zero is suspicious. "t" leaks when it is zero. Linux-PAM-1.5.1/modules/pam_filter/pam_filter.c:357: remediation: Did you intend to include equality with zero? Linux-PAM-1.5.1/modules/pam_filter/pam_filter.c:367: leaked_handle: Handle variable "t" going out of scope leaks the handle. 365| pam_syslog(pamh, LOG_ERR, 366| "child cannot become new session: %m"); 367|-> return PAM_ABORT; 368| } 369| Signed-off-by: Iker Pedrosa --- modules/pam_filter/pam_filter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/modules/pam_filter/pam_filter.c b/modules/pam_filter/pam_filter.c index 2f0af4fb..6e6def37 100644 --- a/modules/pam_filter/pam_filter.c +++ b/modules/pam_filter/pam_filter.c @@ -354,7 +354,7 @@ set_filter (pam_handle_t *pamh, int flags UNUSED, int ctrl, int t = open("/dev/tty", O_RDWR|O_NOCTTY); #else int t = open("/dev/tty",O_RDWR); - if (t > 0) { + if (t >= 0) { (void) ioctl(t, TIOCNOTTY, NULL); close(t); } -- 2.31.1