[PATCH net] octeontx2-af: fix out-of-bounds read setting MSI-X irq affinity

[Ratheesh Kannoth]

From: Anshumali Gaur <agaur@xxxxxxxxxxx>

rvu_register_interrupts() walks every MSI-X vector and uses strstr()
to match "Mbox" or "FLR" in irq_name before pinning those interrupts
to CPU 0. irq_name is a per-vector NAME_SIZE buffer, but not every
slot is populated before this loop runs. strstr() keeps scanning until
it finds a NUL terminator, so an uninitialized slot can trigger a KASAN
slab-out-of-bounds read at boot when debug options are enabled.

Use strnstr() with NAME_SIZE to bound the search within each vector's
name buffer.

Fixes: 4e527f1e5c15 ("octeontx2-af: npc: cn20k: Add new mailboxes for CN20K silicon")
Signed-off-by: Anshumali Gaur <agaur@xxxxxxxxxxx>
Signed-off-by: Ratheesh Kannoth <rkannoth@xxxxxxxxxxx>
---
 drivers/net/ethernet/marvell/octeontx2/af/rvu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
index ffba56ee8a60..43062390aa4c 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
@@ -3331,8 +3331,8 @@ static int rvu_register_interrupts(struct rvu *rvu)
 		goto fail;
 
 	for (i = 0; i < rvu->num_vec; i++) {
-		if (strstr(&rvu->irq_name[i * NAME_SIZE], "Mbox") ||
-		    strstr(&rvu->irq_name[i * NAME_SIZE], "FLR"))
+		if (strnstr(&rvu->irq_name[i * NAME_SIZE], "Mbox", NAME_SIZE) ||
+		    strnstr(&rvu->irq_name[i * NAME_SIZE], "FLR", NAME_SIZE))
 			irq_set_affinity(pci_irq_vector(rvu->pdev, i),
 					 cpumask_of(0));
 	}
-- 
2.43.0