[SSSD] [PATCH 1/3] Revert "Avoid accessing half-deallocated memory when using talloc_zfree macro."

Stephen Gallagher sgallagh at redhat.com
Wed Nov 14 20:07:18 UTC 2012


On Wed 14 Nov 2012 01:35:21 PM EST, Dmitri Pal wrote:
> On 11/14/2012 11:06 AM, Jakub Hrozek wrote:
>> On Wed, Nov 14, 2012 at 05:01:34PM +0100, Pavel Březina wrote:
>>> On 11/14/2012 03:01 PM, Simo Sorce wrote:
>>>> This reverts commit ff57c6aeb80a52b1f52bd1dac9308a69dc7a4774.
>>>>
>>>> This commit doesn't really make sense, we are never accessing freed
>>>> memory as all we are dealing with is a pointer which is never itsef
>>>> part of the memory we are freeing (if it were, it would be an error
>>>> in the caller and we shouldn't mask it in this macro).
>>>> ---
>>>>   src/util/util.h |    6 +-----
>>>>   1 files changed, 1 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/src/util/util.h b/src/util/util.h
>>>> index b6ecfc2c952bd6a37f49194d961b3f762c9546e7..66bae505df2779dbfc065a09162fd789fef9e835 100644
>>>> --- a/src/util/util.h
>>>> +++ b/src/util/util.h
>>>> @@ -228,11 +228,7 @@ errno_t set_debug_file_from_fd(const int fd);
>>>>   #define FLAGS_PID_FILE 0x0004
>>>>
>>>>   #ifndef talloc_zfree
>>>> -#define talloc_zfree(ptr) do { \
>>>> -        TALLOC_CTX *_tmp_ctx = ptr; \
>>>> -        ptr = NULL; \
>>>> -        talloc_free(_tmp_ctx); \
>>>> -    } while(0)
>>>> +#define talloc_zfree(ptr) do { talloc_free(ptr); ptr = NULL; } while(0)
>>>>   #endif
>>>>
>>>>   #ifndef discard_const_p
>>> Hi, we can use TALLOC_FREE(ctx) here, which comes from talloc.h and
>>> is identical to this macro.
>> Is it present even in very old talloc versions? We still support RHEL5..
>> _______________________________________________
>> sssd-devel mailing list
>> sssd-devel at lists.fedorahosted.org
>> https://lists.fedorahosted.org/mailman/listinfo/sssd-devel
> Why this is a concern?
> We do not plan to support any of the latest versions on RHEL5. It is
> less and less needed as we move forward.
> I think it would be safe to say that 1.9 was the last version we build
> for RHEL5.
>

It's also irrelevant, since RHEL carries libtalloc 2.0.x, which is 
recent enough.



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