On 19/04/23 13:02, Sergey Bugaev wrote:
> When opening a temporary file without O_CLOEXEC we risk leaking the
> file descriptor if another thread calls (fork and then) exec while we
> have the fd open. Fix this by consistently passing O_CLOEXEC everywhere
> where we open a file for internal use (and not to return it to the user,
> in which case the API defines whether or not the close-on-exec flag
> shall be set on the returned fd).
>
> Reviewed-by: Adhemerval Zanella <adhemerval.zane...@linaro.org>
> Signed-off-by: Sergey Bugaev <buga...@gmail.com>
LGTM, thanks. I can be installed independently.
> ---
> catgets/open_catalog.c | 4 ++--
> elf/dl-profile.c | 3 ++-
> gmon/gmon.c | 7 ++++---
> iconv/gconv_cache.c | 2 +-
> login/utmp_file.c | 2 +-
> sysdeps/pthread/sem_open.c | 9 ++++++---
> 6 files changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/catgets/open_catalog.c b/catgets/open_catalog.c
> index 242709db..46c444d2 100644
> --- a/catgets/open_catalog.c
> +++ b/catgets/open_catalog.c
> @@ -49,7 +49,7 @@ __open_catalog (const char *cat_name, const char *nlspath,
> const char *env_var,
> char *buf = NULL;
>
> if (strchr (cat_name, '/') != NULL || nlspath == NULL)
> - fd = __open_nocancel (cat_name, O_RDONLY);
> + fd = __open_nocancel (cat_name, O_RDONLY | O_CLOEXEC);
> else
> {
> const char *run_nlspath = nlspath;
> @@ -177,7 +177,7 @@ __open_catalog (const char *cat_name, const char
> *nlspath, const char *env_var,
>
> if (bufact != 0)
> {
> - fd = __open_nocancel (buf, O_RDONLY);
> + fd = __open_nocancel (buf, O_RDONLY | O_CLOEXEC);
> if (fd >= 0)
> break;
> }
> diff --git a/elf/dl-profile.c b/elf/dl-profile.c
> index 2ecac05f..d8345da2 100644
> --- a/elf/dl-profile.c
> +++ b/elf/dl-profile.c
> @@ -324,7 +324,8 @@ _dl_start_profile (void)
> *cp++ = '/';
> __stpcpy (__stpcpy (cp, GLRO(dl_profile)), ".profile");
>
> - fd = __open64_nocancel (filename, O_RDWR|O_CREAT|O_NOFOLLOW, DEFFILEMODE);
> + fd = __open64_nocancel (filename, O_RDWR | O_CREAT | O_NOFOLLOW
> + | O_CLOEXEC, DEFFILEMODE);
> if (fd == -1)
> {
> char buf[400];
> diff --git a/gmon/gmon.c b/gmon/gmon.c
> index bc0e2943..6439ed1c 100644
> --- a/gmon/gmon.c
> +++ b/gmon/gmon.c
> @@ -384,13 +384,14 @@ write_gmon (void)
> size_t len = strlen (env);
> char buf[len + 20];
> __snprintf (buf, sizeof (buf), "%s.%u", env, __getpid ());
> - fd = __open_nocancel (buf, O_CREAT|O_TRUNC|O_WRONLY|O_NOFOLLOW, 0666);
> + fd = __open_nocancel (buf, O_CREAT | O_TRUNC | O_WRONLY | O_NOFOLLOW
> + | O_CLOEXEC, 0666);
> }
>
> if (fd == -1)
> {
> - fd = __open_nocancel ("gmon.out", O_CREAT|O_TRUNC|O_WRONLY|O_NOFOLLOW,
> - 0666);
> + fd = __open_nocancel ("gmon.out", O_CREAT | O_TRUNC | O_WRONLY
> + | O_NOFOLLOW | O_CLOEXEC, 0666);
> if (fd < 0)
> {
> char buf[300];
> diff --git a/iconv/gconv_cache.c b/iconv/gconv_cache.c
> index f2100ca8..87136e24 100644
> --- a/iconv/gconv_cache.c
> +++ b/iconv/gconv_cache.c
> @@ -58,7 +58,7 @@ __gconv_load_cache (void)
> return -1;
>
> /* See whether the cache file exists. */
> - fd = __open_nocancel (GCONV_MODULES_CACHE, O_RDONLY, 0);
> + fd = __open_nocancel (GCONV_MODULES_CACHE, O_RDONLY | O_CLOEXEC, 0);
> if (__builtin_expect (fd, 0) == -1)
> /* Not available. */
> return -1;
> diff --git a/login/utmp_file.c b/login/utmp_file.c
> index 53494595..1ef07821 100644
> --- a/login/utmp_file.c
> +++ b/login/utmp_file.c
> @@ -463,7 +463,7 @@ __libc_updwtmp (const char *file, const struct utmp *utmp)
> int fd;
>
> /* Open WTMP file. */
> - fd = __open_nocancel (file, O_WRONLY | O_LARGEFILE);
> + fd = __open_nocancel (file, O_WRONLY | O_LARGEFILE | O_CLOEXEC);
> if (fd < 0)
> return -1;
>
> diff --git a/sysdeps/pthread/sem_open.c b/sysdeps/pthread/sem_open.c
> index 2d32a135..e5db929d 100644
> --- a/sysdeps/pthread/sem_open.c
> +++ b/sysdeps/pthread/sem_open.c
> @@ -36,6 +36,7 @@ sem_t *
> __sem_open (const char *name, int oflag, ...)
> {
> int fd;
> + int open_flags;
> sem_t *result;
>
> /* Check that shared futexes are supported. */
> @@ -64,9 +65,10 @@ __sem_open (const char *name, int oflag, ...)
> /* If the semaphore object has to exist simply open it. */
> if ((oflag & O_CREAT) == 0 || (oflag & O_EXCL) == 0)
> {
> + open_flags = O_RDWR | O_NOFOLLOW | O_CLOEXEC;
> + open_flags |= (oflag & ~(O_CREAT|O_ACCMODE));
> try_again:
> - fd = __open (dirname.name,
> - (oflag & ~(O_CREAT|O_ACCMODE)) | O_NOFOLLOW | O_RDWR);
> + fd = __open (dirname.name, open_flags);
>
> if (fd == -1)
> {
> @@ -133,7 +135,8 @@ __sem_open (const char *name, int oflag, ...)
> }
>
> /* Open the file. Make sure we do not overwrite anything. */
> - fd = __open (tmpfname, O_RDWR | O_CREAT | O_EXCL, mode);
> + open_flags = O_RDWR | O_CREAT | O_EXCL | O_CLOEXEC;
> + fd = __open (tmpfname, open_flags, mode);
> if (fd == -1)
> {
> if (errno == EEXIST)
