support: Also return fd when it is 0

Message ID 20211006162545.12778-1-siddhesh@sourceware.org
State New
Headers show
Series
  • support: Also return fd when it is 0
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Commit Message

The fd validity check in open_dev_null checks if fd > 0, which would
lead to a leaked fd if it is == 0.


I also went ahead and adjusted formatting of the file since it was off.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

---

- I own copyright for my submissions to glibc, so using S-o-b
- This is a trivial fix, so I'll push it if there are no objections.

 support/support-open-dev-null-range.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

-- 
2.31.1

Comments

On 06/10/2021 13:25, Siddhesh Poyarekar via Libc-alpha wrote:
> The fd validity check in open_dev_null checks if fd > 0, which would

> lead to a leaked fd if it is == 0.

> 

> 

> I also went ahead and adjusted formatting of the file since it was off.

> 

> Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>


LGTM, thanks.  Please also backport it to 2.34.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>


> ---

> 

> - I own copyright for my submissions to glibc, so using S-o-b

> - This is a trivial fix, so I'll push it if there are no objections.

> 

>  support/support-open-dev-null-range.c | 14 +++++++-------

>  1 file changed, 7 insertions(+), 7 deletions(-)

> 

> diff --git a/support/support-open-dev-null-range.c b/support/support-open-dev-null-range.c

> index 80d9dba504..66a8504105 100644

> --- a/support/support-open-dev-null-range.c

> +++ b/support/support-open-dev-null-range.c

> @@ -40,16 +40,16 @@ increase_nofile (void)

>  static int

>  open_dev_null (int flags, mode_t mode)

>  {

> - int fd = open64 ("/dev/null", flags, mode);

> - if (fd > 0)

> -   return fd;

> +  int fd = open64 ("/dev/null", flags, mode);

> +  if (fd >= 0)

> +    return fd;

>  

> - if (fd < 0 && errno != EMFILE)

> -   FAIL_EXIT1 ("open64 (\"/dev/null\", 0x%x, 0%o): %m", flags, mode);

> +  if (fd < 0 && errno != EMFILE)

> +    FAIL_EXIT1 ("open64 (\"/dev/null\", 0x%x, 0%o): %m", flags, mode);

>  

> - increase_nofile ();

> +  increase_nofile ();

>  

> - return xopen ("/dev/null", flags, mode);

> +  return xopen ("/dev/null", flags, mode);

>  }

>  

>  struct range

>

Patch

diff --git a/support/support-open-dev-null-range.c b/support/support-open-dev-null-range.c
index 80d9dba504..66a8504105 100644
--- a/support/support-open-dev-null-range.c
+++ b/support/support-open-dev-null-range.c
@@ -40,16 +40,16 @@  increase_nofile (void)
 static int
 open_dev_null (int flags, mode_t mode)
 {
- int fd = open64 ("/dev/null", flags, mode);
- if (fd > 0)
-   return fd;
+  int fd = open64 ("/dev/null", flags, mode);
+  if (fd >= 0)
+    return fd;
 
- if (fd < 0 && errno != EMFILE)
-   FAIL_EXIT1 ("open64 (\"/dev/null\", 0x%x, 0%o): %m", flags, mode);
+  if (fd < 0 && errno != EMFILE)
+    FAIL_EXIT1 ("open64 (\"/dev/null\", 0x%x, 0%o): %m", flags, mode);
 
- increase_nofile ();
+  increase_nofile ();
 
- return xopen ("/dev/null", flags, mode);
+  return xopen ("/dev/null", flags, mode);
 }
 
 struct range