[PATCH] Fix lpfc oops when parsing dodgy VPD

[PATCH] Fix lpfc oops when parsing dodgy VPD

[Anton Blanchard]

We have seen two cases where VPD on an emulex card has been incorrect
and we end up walking off the end of memory. It looks like someone made
an update (increased the length of a string) without increasing the
Length field. Then we do:

	Length -= (3+i);

And since Length is unsigned it becomes very large and we loop forever
in the encapsulating:

	while (Length > 0) {

If we make Length signed then we fall out of the loop and proceed on.

Its important to note we have only seen this in the lab and it may be
the only two cases of this in existence, but since the rest of the code
has been written to be resilient against bad VPD we may as well fix this
too.

Signed-off-by: Anton Blanchard <anton@samba.org>
---

Index: kernel/drivers/scsi/lpfc/lpfc_init.c
===================================================================
--- kernel.orig/drivers/scsi/lpfc/lpfc_init.c	2007-02-07 17:02:43.000000000 -0600
+++ kernel/drivers/scsi/lpfc/lpfc_init.c	2007-02-07 17:23:31.000000000 -0600
@@ -662,7 +662,7 @@
 lpfc_parse_vpd(struct lpfc_hba * phba, uint8_t * vpd, int len)
 {
 	uint8_t lenlo, lenhi;
-	uint32_t Length;
+	int Length;
 	int i, j;
 	int finished = 0;
 	int index = 0;

Re: [PATCH] Fix lpfc oops when parsing dodgy VPD

[James Smart]

ACK.

To my knowledge bad VPD data had only been found on early prototypes, as they
avoided the typical "manufacturing process".  Regardless, we do try to be
preventative about this type of thing, just in case.

Thanks

-- james s


Anton Blanchard wrote:
> We have seen two cases where VPD on an emulex card has been incorrect
> and we end up walking off the end of memory. It looks like someone made
> an update (increased the length of a string) without increasing the
> Length field. Then we do:
> 
> 	Length -= (3+i);
> 
> And since Length is unsigned it becomes very large and we loop forever
> in the encapsulating:
> 
> 	while (Length > 0) {
> 
> If we make Length signed then we fall out of the loop and proceed on.
> 
> Its important to note we have only seen this in the lab and it may be
> the only two cases of this in existence, but since the rest of the code
> has been written to be resilient against bad VPD we may as well fix this
> too.
> 
> Signed-off-by: Anton Blanchard <anton@samba.org>
> ---
> 
> Index: kernel/drivers/scsi/lpfc/lpfc_init.c
> ===================================================================
> --- kernel.orig/drivers/scsi/lpfc/lpfc_init.c	2007-02-07 17:02:43.000000000 -0600
> +++ kernel/drivers/scsi/lpfc/lpfc_init.c	2007-02-07 17:23:31.000000000 -0600
> @@ -662,7 +662,7 @@
>  lpfc_parse_vpd(struct lpfc_hba * phba, uint8_t * vpd, int len)
>  {
>  	uint8_t lenlo, lenhi;
> -	uint32_t Length;
> +	int Length;
>  	int i, j;
>  	int finished = 0;
>  	int index = 0;
>