On Thu, Mar 26, 2020 at 01:03:26AM +0100, Tobias Heider wrote:
> sr_block_get() returns dma_alloc(length, PR_NOWAIT | PR_ZERO) which may be
> NULL if the memory pool is depleted.
> The result is used as 'dst' argument to memcpy() in the following call to
> sr_raid5_regenerate(), resulting in a possible NULL dereference.
> 
> ok?
> 
> Index: softraid_raid5.c
> ===================================================================
> RCS file: /mount/openbsd/cvs/src/sys/dev/softraid_raid5.c,v
> retrieving revision 1.29
> diff -u -p -r1.29 softraid_raid5.c
> --- softraid_raid5.c  8 Aug 2019 02:19:55 -0000       1.29
> +++ softraid_raid5.c  25 Mar 2020 23:54:25 -0000
> @@ -818,7 +818,8 @@ sr_raid5_rebuild(struct sr_discipline *s
>               wu_w = sr_scsi_wu_get(sd, 0);
>               wu_r = sr_scsi_wu_get(sd, 0);
>  
> -             xorbuf = sr_block_get(sd, strip_size);
> +             if ((xorbuf = sr_block_get(sd, strip_size)) == NULL)
> +                     goto bad;
>               if (sr_raid5_regenerate(wu_r, rebuild_chunk, chunk_lba,
>                   strip_size, xorbuf))
>                       goto bad;
> 

Obvious fix. ok stsp@

Same problem is present in sr_raid5_scrub() which is currently in #if 0.

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