From 9f19e7da7a014e022cdbba06accca171adef27e0 Mon Sep 17 00:00:00 2001 From: Christian Göttsche Date: Thu, 4 Jan 2024 18:23:59 +0100 Subject: pam_unix: set close-on-exec Since the module operates on sensitive files set the close-on-exec flag, to avoid file descriptor leaks if there is ever any sibling thread. The fopen(3) mode "e" is supported in glibc since version 2.7 (released in 2007), and ignored prior, see: https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=65d834b0add966dbbdb5ed1e916c60b2b2d87f10 --- modules/pam_unix/lckpwdf.-c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) (limited to 'modules/pam_unix/lckpwdf.-c') diff --git a/modules/pam_unix/lckpwdf.-c b/modules/pam_unix/lckpwdf.-c index c3e63155..4d0f0ad3 100644 --- a/modules/pam_unix/lckpwdf.-c +++ b/modules/pam_unix/lckpwdf.-c @@ -35,15 +35,6 @@ static int lockfd = -1; -static int set_close_on_exec(int fd) -{ - int flags = fcntl(fd, F_GETFD, 0); - if (flags == -1) - return -1; - flags |= FD_CLOEXEC; - return fcntl(fd, F_SETFD, flags); -} - static int do_lock(int fd) { struct flock fl; @@ -70,7 +61,7 @@ static int lckpwdf(void) #ifdef WITH_SELINUX if(is_selinux_enabled()>0) { - lockfd = open(LOCKFILE, O_WRONLY); + lockfd = open(LOCKFILE, O_WRONLY | O_CLOEXEC); if(lockfd == -1 && errno == ENOENT) { char *create_context_raw; @@ -82,18 +73,16 @@ static int lckpwdf(void) freecon(create_context_raw); if(rc) return -1; - lockfd = open(LOCKFILE, O_CREAT | O_WRONLY, 0600); + lockfd = open(LOCKFILE, O_CREAT | O_WRONLY | O_CLOEXEC, 0600); if(setfscreatecon_raw(NULL)) return -1; } } else #endif - lockfd = open(LOCKFILE, O_CREAT | O_WRONLY, 0600); + lockfd = open(LOCKFILE, O_CREAT | O_WRONLY | O_CLOEXEC, 0600); if (lockfd == -1) return -1; - if (set_close_on_exec(lockfd) == -1) - goto cleanup_fd; memset(&act, 0, sizeof act); act.sa_handler = alarm_catch; -- cgit v1.2.3