* [PATCH v1] nis: Fix leak on realloc failure in nis_getnames
@ 2021-07-28 17:47 Robbie Harwood
2021-07-28 18:03 ` Florian Weimer
2021-07-28 18:06 ` [PATCH v1] nis: Fix leak on realloc failure in nis_getnames Robbie Harwood
0 siblings, 2 replies; 5+ messages in thread
From: Robbie Harwood @ 2021-07-28 17:47 UTC (permalink / raw)
To: libc-alpha
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[-- Attachment #1: v1-0001-nis-Fix-leak-on-realloc-failure-in-nis_getnames.patch --]
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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;
--
2.32.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v1] nis: Fix leak on realloc failure in nis_getnames
2021-07-28 17:47 [PATCH v1] nis: Fix leak on realloc failure in nis_getnames Robbie Harwood
@ 2021-07-28 18:03 ` Florian Weimer
2021-07-28 18:23 ` [PATCH v2 1/1] nis: Fix leak on realloc failure in nis_getnames [BZ #28150] Robbie Harwood
2021-07-28 18:06 ` [PATCH v1] nis: Fix leak on realloc failure in nis_getnames Robbie Harwood
1 sibling, 1 reply; 5+ messages in thread
From: Florian Weimer @ 2021-07-28 18:03 UTC (permalink / raw)
To: Robbie Harwood via Libc-alpha; +Cc: Robbie Harwood
* 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
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v1] nis: Fix leak on realloc failure in nis_getnames
2021-07-28 17:47 [PATCH v1] nis: Fix leak on realloc failure in nis_getnames Robbie Harwood
2021-07-28 18:03 ` Florian Weimer
@ 2021-07-28 18:06 ` Robbie Harwood
1 sibling, 0 replies; 5+ messages in thread
From: Robbie Harwood @ 2021-07-28 18:06 UTC (permalink / raw)
To: libc-alpha; +Cc: Robbie Harwood, kukuk
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;
--
2.32.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2 1/1] nis: Fix leak on realloc failure in nis_getnames [BZ #28150]
2021-07-28 18:03 ` Florian Weimer
@ 2021-07-28 18:23 ` Robbie Harwood
2021-08-02 15:24 ` Carlos O'Donell
0 siblings, 1 reply; 5+ messages in thread
From: Robbie Harwood @ 2021-07-28 18:23 UTC (permalink / raw)
To: libc-alpha, fweimer; +Cc: Robbie Harwood, kukuk
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;
--
2.32.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 1/1] nis: Fix leak on realloc failure in nis_getnames [BZ #28150]
2021-07-28 18:23 ` [PATCH v2 1/1] nis: Fix leak on realloc failure in nis_getnames [BZ #28150] Robbie Harwood
@ 2021-08-02 15:24 ` Carlos O'Donell
0 siblings, 0 replies; 5+ messages in thread
From: Carlos O'Donell @ 2021-08-02 15:24 UTC (permalink / raw)
To: Robbie Harwood, libc-alpha, fweimer
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;
>
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-08-02 15:24 UTC | newest]
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2021-07-28 17:47 [PATCH v1] nis: Fix leak on realloc failure in nis_getnames Robbie Harwood
2021-07-28 18:03 ` Florian Weimer
2021-07-28 18:23 ` [PATCH v2 1/1] nis: Fix leak on realloc failure in nis_getnames [BZ #28150] Robbie Harwood
2021-08-02 15:24 ` Carlos O'Donell
2021-07-28 18:06 ` [PATCH v1] nis: Fix leak on realloc failure in nis_getnames Robbie Harwood
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