diff options
| -rw-r--r-- | configure.ac | 2 | ||||
| -rw-r--r-- | libpam/pam_modutil_sanitize.c | 73 |
2 files changed, 60 insertions, 15 deletions
diff --git a/configure.ac b/configure.ac index e9d44769..e4995fc9 100644 --- a/configure.ac +++ b/configure.ac @@ -508,7 +508,7 @@ dnl Checks for header files. AC_HEADER_DIRENT AC_HEADER_STDC AC_HEADER_SYS_WAIT -AC_CHECK_HEADERS(fcntl.h limits.h malloc.h sys/file.h sys/ioctl.h sys/time.h syslog.h net/if.h termio.h unistd.h sys/fsuid.h inittypes.h) +AC_CHECK_HEADERS(fcntl.h limits.h malloc.h sys/file.h sys/ioctl.h sys/time.h syslog.h net/if.h termio.h unistd.h sys/fsuid.h inittypes.h sys/vfs.h linux/magic.h) dnl For module/pam_lastlog AC_CHECK_HEADERS(lastlog.h utmp.h utmpx.h) diff --git a/libpam/pam_modutil_sanitize.c b/libpam/pam_modutil_sanitize.c index 65f85d01..605c859d 100644 --- a/libpam/pam_modutil_sanitize.c +++ b/libpam/pam_modutil_sanitize.c @@ -10,6 +10,13 @@ #include <fcntl.h> #include <syslog.h> #include <sys/resource.h> +#include <dirent.h> +#ifdef HAVE_SYS_VFS_H +#include <sys/vfs.h> +#endif +#ifdef HAVE_LINUX_MAGIC_H +#include <linux/magic.h> +#endif /* * Creates a pipe, closes its write end, redirects fd to its read end. @@ -112,31 +119,69 @@ redirect_out(pam_handle_t *pamh, enum pam_modutil_redirect_fd mode, return fd; } +/* Check if path is in a procfs. */ +static int +is_in_procfs(int fd) +{ +#if defined HAVE_SYS_VFS_H && defined PROC_SUPER_MAGIC + struct statfs stfs; + + if (fstatfs(fd, &stfs) == 0) { + if (stfs.f_type == PROC_SUPER_MAGIC) + return 1; + } else { + return 0; + } +#endif /* HAVE_SYS_VFS_H && PROC_SUPER_MAGIC */ + + return -1; +} + /* Closes all descriptors after stderr. */ static void close_fds(void) { + DIR *dir = NULL; + struct dirent *dent; + int dfd = -1; + int fd; + struct rlimit rlim; + /* * An arbitrary upper limit for the maximum file descriptor number * returned by RLIMIT_NOFILE. */ - const int MAX_FD_NO = 65535; + const unsigned int MAX_FD_NO = 65535; /* The lower limit is the same as for _POSIX_OPEN_MAX. */ - const int MIN_FD_NO = 20; - - int fd; - struct rlimit rlim; - - if (getrlimit(RLIMIT_NOFILE, &rlim) || rlim.rlim_max > MAX_FD_NO) - fd = MAX_FD_NO; - else if (rlim.rlim_max < MIN_FD_NO) - fd = MIN_FD_NO; - else - fd = rlim.rlim_max - 1; + const unsigned int MIN_FD_NO = 20; + + /* If /proc is mounted, we can optimize which fd can be closed. */ + if ((dir = opendir("/proc/self/fd")) != NULL) { + if ((dfd = dirfd(dir)) >= 0 && is_in_procfs(dfd) > 0) { + while ((dent = readdir(dir)) != NULL) { + fd = atoi(dent->d_name); + if (fd > STDERR_FILENO && fd != dfd) + close(fd); + } + } else { + dfd = -1; + } + closedir(dir); + } - for (; fd > STDERR_FILENO; --fd) - close(fd); + /* If /proc isn't available, fallback to the previous behavior. */ + if (dfd < 0) { + if (getrlimit(RLIMIT_NOFILE, &rlim) || rlim.rlim_max > MAX_FD_NO) + fd = MAX_FD_NO; + else if (rlim.rlim_max < MIN_FD_NO) + fd = MIN_FD_NO; + else + fd = rlim.rlim_max - 1; + + for (; fd > STDERR_FILENO; --fd) + close(fd); + } } int |