[v1] nis: Fix leak on realloc failure in nis_getnames
Checks
| Context |
Check |
Description |
| dj/TryBot-apply_patch |
success
|
Patch applied to master at the time it was sent
|
| dj/TryBot-32bit |
success
|
Build for i686
|
Commit Message
Comments
* Robbie Harwood via Libc-alpha:
> From 7aa0a9f879d5b2117beb06771bb4fdbaf25699a9 Mon Sep 17 00:00:00 2001
> From: Robbie Harwood <rharwood@redhat.com>
> Date: Wed, 28 Jul 2021 12:54:44 -0400
> Subject: [PATCH v1] nis: Fix leak on realloc failure in nis_getnames
> To: libc-alpha@sourceware.org
> Cc: kukuk@suse.de
>
> 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(-)
>
> 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;
The patch looks correct to me. (There some similar code above, but it
is already correct because the tmp ownership transfer is different.)
Would you please open a bug in Bugzilla and reference it in the commit
message.
I don't think we need to treat this as a security vulnerability (denial
of service) because since bug only happens after a memory allocation
failure, and at that point, the service is already denied, so to speak.
Thanks,
Florian
From 7aa0a9f879d5b2117beb06771bb4fdbaf25699a9 Mon Sep 17 00:00:00 2001
From: Robbie Harwood <rharwood@redhat.com>
Date: Wed, 28 Jul 2021 12:54:44 -0400
Subject: [PATCH v1] nis: Fix leak on realloc failure in nis_getnames
To: libc-alpha@sourceware.org
Cc: kukuk@suse.de
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(-)
@@ -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;
--
2.32.0