Small memory leak in execute.c of ECPG driver

On 02/03/2015 08:58 AM, Michael Paquier wrote:

Hi all,

In exactly 3 places of the ECPG driver (for numeric, for interval and
for date), we do something as follows:
/* Allocation of mallocedval */
if (!(mallocedval = ecpg_strdup("array [", lineno)))
return false;

for (element = 0; element < var->arrsize; element++)
{
int result;

ptr = stuff_alloc();
if (!ptr)
return false; <= Leak here of mallocedval

It happens that if the allocation done within this for loop fails we
leak mallocedval that was previously allocated. Attached is a patch to
fix this issue spotted by Coverity.

I think there are more similar leaks nearby. After the first hunk,
there's another if-check with "return false" that also leaks
mallocedval. Right after the two other hunks, if the ecpg_realloc fails,
we again leak mallocedval.

I wonder why Coverity didn't warn about those? Maybe it would've, after
fixing the first ones.

- Heikki

--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers

On Tue, Feb 3, 2015 at 5:35 PM, Heikki Linnakangas
<hlinnakangas@vmware.com> wrote:

I think there are more similar leaks nearby. After the first hunk, there's
another if-check with "return false" that also leaks mallocedval. Right
after the two other hunks, if the ecpg_realloc fails, we again leak
mallocedval.

Yes, I found some extra ones by re-reading the code again with newcopy
(2) as well as mallocedval (1) as you mentioned.

I wonder why Coverity didn't warn about those? Maybe it would've, after
fixing the first ones.

Hard to say. Perhaps it gives up after finding one failure in a code
path, or perhaps it would have found it after a version update.. In
any case, an updated patch is attached.
--
Michael

On 02/03/2015 02:45 PM, Michael Paquier wrote:

On Tue, Feb 3, 2015 at 5:35 PM, Heikki Linnakangas
<hlinnakangas@vmware.com> wrote:

I think there are more similar leaks nearby. After the first hunk, there's
another if-check with "return false" that also leaks mallocedval. Right
after the two other hunks, if the ecpg_realloc fails, we again leak
mallocedval.

Yes, I found some extra ones by re-reading the code again with newcopy
(2) as well as mallocedval (1) as you mentioned.

Committed, along with more fixes for leaks on ecpg_realloc failures.

- Heikki

--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers