[PATCH] Initialize local relocator subchunk struct to all zeros

[PATCH] Initialize local relocator subchunk struct to all zeros

[Ross Philipson]

The way the code is written the tofree variable would never be
passed to the free_subchunk() function uninitialized. Coverity
cannot determine this and flags the situation as "Using uninitialized
value...". The fix is just to initialize the local struct.

Fixes: CID 314016

Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
---
 grub-core/lib/relocator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/grub-core/lib/relocator.c b/grub-core/lib/relocator.c
index 68ef128..bfcc70d 100644
--- a/grub-core/lib/relocator.c
+++ b/grub-core/lib/relocator.c
@@ -989,7 +989,7 @@ malloc_in_range (struct grub_relocator *rel,
 	if (j != 0 && events[j - 1].pos != events[j].pos)
 	  {
 	    grub_addr_t alloc_start, alloc_end;
-	    struct grub_relocator_subchunk tofree;
+	    struct grub_relocator_subchunk tofree = {0};
 	    struct grub_relocator_subchunk *curschu = &tofree;
 	    if (!oom)
 	      curschu = &res->subchunks[cural];
-- 
1.8.3.1

Re: [PATCH] Initialize local relocator subchunk struct to all zeros

[Darren Kenny]

Hi Ross,

This looks good to me.

On Thursday, 2022-07-14 at 09:41:28 -04, Ross Philipson wrote:
> The way the code is written the tofree variable would never be
> passed to the free_subchunk() function uninitialized. Coverity
> cannot determine this and flags the situation as "Using uninitialized
> value...". The fix is just to initialize the local struct.
>
> Fixes: CID 314016
>
> Signed-off-by: Ross Philipson <ross.philipson@oracle.com>

Reviewed-by: Darren Kenny <darren.kenny@oracle.com>

Thanks,

Darren.

> ---
>  grub-core/lib/relocator.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/grub-core/lib/relocator.c b/grub-core/lib/relocator.c
> index 68ef128..bfcc70d 100644
> --- a/grub-core/lib/relocator.c
> +++ b/grub-core/lib/relocator.c
> @@ -989,7 +989,7 @@ malloc_in_range (struct grub_relocator *rel,
>  	if (j != 0 && events[j - 1].pos != events[j].pos)
>  	  {
>  	    grub_addr_t alloc_start, alloc_end;
> -	    struct grub_relocator_subchunk tofree;
> +	    struct grub_relocator_subchunk tofree = {0};
>  	    struct grub_relocator_subchunk *curschu = &tofree;
>  	    if (!oom)
>  	      curschu = &res->subchunks[cural];
> -- 
> 1.8.3.1

Re: [PATCH] Initialize local relocator subchunk struct to all zeros

[Alec Brown]

On Thu, Jul 14, 2022 at 03:38:04PM +0100, Darren Kenny wrote:
> Hi Ross,
> 
> This looks good to me.
> 
> On Thursday, 2022-07-14 at 09:41:28 -04, Ross Philipson wrote:
> > The way the code is written the tofree variable would never be
> > passed to the free_subchunk() function uninitialized. Coverity
> > cannot determine this and flags the situation as "Using uninitialized
> > value...". The fix is just to initialize the local struct.
> >
> > Fixes: CID 314016
> >
> > Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
> 
> Reviewed-by: Darren Kenny <darren.kenny@oracle.com>

I ran this through a private Coverity scan which marked the bug as eliminated
and didn't have any issues running it on a VM.

Tested-by: Alec Brown <alec.r.brown@oracle.com>

Alec Brown

> 
> Thanks,
> 
> Darren.
> 
> > ---
> >  grub-core/lib/relocator.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/grub-core/lib/relocator.c b/grub-core/lib/relocator.c
> > index 68ef128..bfcc70d 100644
> > --- a/grub-core/lib/relocator.c
> > +++ b/grub-core/lib/relocator.c
> > @@ -989,7 +989,7 @@ malloc_in_range (struct grub_relocator *rel,
> >  	if (j != 0 && events[j - 1].pos != events[j].pos)
> >  	  {
> >  	    grub_addr_t alloc_start, alloc_end;
> > -	    struct grub_relocator_subchunk tofree;
> > +	    struct grub_relocator_subchunk tofree = {0};
> >  	    struct grub_relocator_subchunk *curschu = &tofree;
> >  	    if (!oom)
> >  	      curschu = &res->subchunks[cural];
> > -- 
> > 1.8.3.1

Re: [PATCH] Initialize local relocator subchunk struct to all zeros

[Daniel Kiper]

On Fri, Jul 15, 2022 at 05:21:21PM -0400, Alec Brown wrote:
> On Thu, Jul 14, 2022 at 03:38:04PM +0100, Darren Kenny wrote:
> > Hi Ross,
> >
> > This looks good to me.
> >
> > On Thursday, 2022-07-14 at 09:41:28 -04, Ross Philipson wrote:
> > > The way the code is written the tofree variable would never be
> > > passed to the free_subchunk() function uninitialized. Coverity
> > > cannot determine this and flags the situation as "Using uninitialized
> > > value...". The fix is just to initialize the local struct.
> > >
> > > Fixes: CID 314016
> > >
> > > Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
> >
> > Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
>
> I ran this through a private Coverity scan which marked the bug as eliminated
> and didn't have any issues running it on a VM.
>
> Tested-by: Alec Brown <alec.r.brown@oracle.com>

Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Daniel