Date: Tue, 20 Nov 2007 10:57:58 +0300 (MSK) From: Oleg Sharoiko <os@rsu.ru> To: FreeBSD-gnats-submit@FreeBSD.org Subject: bin/118144: [patch] pam_lastlog doesn't check return values in pam_sm_close_session Message-ID: <200711200757.lAK7vwZX096645@brain.cc.rsu.ru> Resent-Message-ID: <200711200830.lAK8U2Bl009960@freefall.freebsd.org>
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>Number: 118144 >Category: bin >Synopsis: [patch] pam_lastlog doesn't check return values in pam_sm_close_session >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Tue Nov 20 08:30:01 UTC 2007 >Closed-Date: >Last-Modified: >Originator: Oleg Sharoiko >Release: FreeBSD 6.2-STABLE i386 >Organization: >Environment: System: FreeBSD brain.cc.rsu.ru 6.2-STABLE FreeBSD 6.2-STABLE #0: Tue Sep 18 16:26:09 MSD 2007 os@brain.cc.rsu.ru:/usr/obj/usr/src/sys/brain.i386.RELENG_6.2007-04-14 i386 >Description: From lib/libpam/modules/pam_lastlog/pam_lastlog.c PAM_EXTERN int pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused, int argc __unused, const char *argv[] __unused) { const void *tty; pam_get_item(pamh, PAM_TTY, (const void **)&tty); if (strncmp(tty, _PATH_DEV, strlen(_PATH_DEV)) == 0) tty = (const char *)tty + strlen(_PATH_DEV); if (*(const char *)tty == '\0') return (PAM_SERVICE_ERR); if (logout(tty) != 1) syslog(LOG_ERR, "%s(): no utmp record for %s", __func__, (const char *)tty); logwtmp(tty, "", ""); return (PAM_SUCCESS); } 1. pam_get_item may fail 2. tty may be NULL resulting in SIGSEGV in strncmp. >How-To-Repeat: >Fix: --- pam_lastlog.c.orig Tue Nov 20 10:05:48 2007 +++ pam_lastlog.c Tue Nov 20 10:07:07 2007 @@ -170,9 +170,14 @@ pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused, int argc __unused, const char *argv[] __unused) { - const void *tty; + const void *tty = NULL; + int pam_err; - pam_get_item(pamh, PAM_TTY, (const void **)&tty); + pam_err = pam_get_item(pamh, PAM_TTY, (const void **)&tty); + if (pam_err != PAM_SUCCESS) + return (pam_err); + if (*tty == NULL) + return (PAM_SERVICE_ERR); if (strncmp(tty, _PATH_DEV, strlen(_PATH_DEV)) == 0) tty = (const char *)tty + strlen(_PATH_DEV); if (*(const char *)tty == '\0') >Release-Note: >Audit-Trail: >Unformatted:
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