[v2,1/1] nis: Fix leak on realloc failure in nis_getnames [BZ #28150]
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Commit Message
If pos >= count but realloc fails, tmp will not have been placed in
getnames[pos] yet, and so will not be freed in free_null. Detected
by Coverity.
Also remove misleading comment from nis_getnames(), since it actually
did properly release getnames when out of memory.
---
nis/nis_subr.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
Comments
On 7/28/21 2:23 PM, Robbie Harwood via Libc-alpha wrote:
> If pos >= count but realloc fails, tmp will not have been placed in
> getnames[pos] yet, and so will not be freed in free_null. Detected
> by Coverity.
>
> Also remove misleading comment from nis_getnames(), since it actually
> did properly release getnames when out of memory.
The CI/CD patchwork trybot didn't trigger for this patch and I need
to review that with DJ.
I tested on x86_64 and i686 without regression. Florian reviewed.
I'm pushing this fix.
Tested-by: Carlos O'Donell <carlos@redhat.com>
> ---
> nis/nis_subr.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/nis/nis_subr.c b/nis/nis_subr.c
> index dd0e30071d..6784fc353f 100644
> --- a/nis/nis_subr.c
> +++ b/nis/nis_subr.c
> @@ -103,9 +103,6 @@ count_dots (const_nis_name str)
> return count;
> }
>
> -/* If we run out of memory, we don't give already allocated memory
> - free. The overhead for bringing getnames back in a safe state to
> - free it is to big. */
> nis_name *
> nis_getnames (const_nis_name name)
> {
> @@ -271,7 +268,10 @@ nis_getnames (const_nis_name name)
> nis_name *newp = realloc (getnames,
> (count + 1) * sizeof (char *));
> if (__glibc_unlikely (newp == NULL))
> - goto free_null;
> + {
> + free (tmp);
> + goto free_null;
> + }
> getnames = newp;
> }
> getnames[pos] = tmp;
>
@@ -103,9 +103,6 @@ count_dots (const_nis_name str)
return count;
}
-/* If we run out of memory, we don't give already allocated memory
- free. The overhead for bringing getnames back in a safe state to
- free it is to big. */
nis_name *
nis_getnames (const_nis_name name)
{
@@ -271,7 +268,10 @@ nis_getnames (const_nis_name name)
nis_name *newp = realloc (getnames,
(count + 1) * sizeof (char *));
if (__glibc_unlikely (newp == NULL))
- goto free_null;
+ {
+ free (tmp);
+ goto free_null;
+ }
getnames = newp;
}
getnames[pos] = tmp;