[pacman-dev] [PATCH v2] pacman/upgrade: Check malloc() return value

[Sören Brinkmann]

Hi Andrew,

On Mon, 2014-03-10 at 10:00AM -0400, Andrew Gregory wrote:
> On 03/09/14 at 03:47pm, Sören Brinkmann wrote:
> > Check the return value of malloc() before dereferencing the returned pointer.
> > 
> > Signed-off-by: Sören Brinkmann <soeren.brinkmann at gmail.com>
> > ---
> > v2:
> >  - add print statement to log the error
> > ---
> >  src/pacman/upgrade.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/src/pacman/upgrade.c b/src/pacman/upgrade.c
> > index 5416f6180b39..11da4dcb5e53 100644
> > --- a/src/pacman/upgrade.c
> > +++ b/src/pacman/upgrade.c
> > @@ -51,6 +51,10 @@ int pacman_upgrade(alpm_list_t *targets)
> >  	 */
> >  	for(i = targets; i; i = alpm_list_next(i)) {
> >  		int *r = malloc(sizeof(int));
> > +		if(r == NULL) {
> > +			pm_printf(ALPM_LOG_ERROR, _("memory exhausted\n"));
> > +			return 1;
> > +		}
> 
> If you move the malloc outside the loop and make it an array we have
> a better chance of hitting this early enough that we still have
> a little memory left for cleanup.

I think that is not done that easily. Actually not without some
significant rewrite of this code. Those allocated rs go into an
alpm_list_t which is eventually freed using FREELIST. Doing the memory
management differently here is not that straight forward.

	Sören