[SCSI] lpfc: fix potential overflow of hbqs array

The Coverity checker noticed that we may overrun a statically allocated
array in drivers/scsi/lpfc/lpfc_sli.c::lpfc_sli_hbqbuf_find().

The case is this; In 'struct lpfc_hba' we have

	#define LPFC_MAX_HBQS  4
	...
	struct lpfc_hba {
		...
		struct hbq_s hbqs[LPFC_MAX_HBQS];
		...
	};

But then in lpfc_sli_hbqbuf_find() we have this code

	hbqno = tag >> 16;
	if (hbqno > LPFC_MAX_HBQS)
		return NULL;

if 'hbqno' ends up as exactely 4, then we won't return, and then this

	list_for_each_entry(d_buf, &phba->hbqs[hbqno].hbq_buffer_list, list) {

will cause an overflow of the statically allocated array at index 4,
since the valid indices are only 0-3.

I propose this patch, that simply changes the 'hbqno > LPFC_MAX_HBQS'
into 'hbqno >= LPFC_MAX_HBQS' as a possible fix.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: James Smart <James.Smart@Emulex.Com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index ce5ff2b..e5337ad 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -675,7 +675,7 @@ lpfc_sli_hbqbuf_find(struct lpfc_hba *phba, uint32_t tag)
        uint32_t hbqno;
 
        hbqno = tag >> 16;
-       if (hbqno > LPFC_MAX_HBQS)
+       if (hbqno >= LPFC_MAX_HBQS)
                return NULL;
 
        list_for_each_entry(d_buf, &phba->hbqs[hbqno].hbq_buffer_list, list) {