[PATCH] net: ethernet: broadcom: sb1250-mac: Add checks for kcalloc() in sbdma_initctx()

[Guangshuo Li]

Two kcalloc() allocations (descriptor table and context table) can fail
and are used unconditionally afterwards (ALIGN()/phys conversion and
dereferences), leading to potential NULL pointer dereference.

Check both allocations and bail out early; on the second failure, free
the first allocation to avoid a leak. Do not emit extra OOM logs.

Fixes: 73d739698017 ("sb1250-mac.c: De-typedef, de-volatile, de-etc...")
Fixes: c477f3348abb ("drivers/net/sb1250-mac.c: kmalloc + memset conversion to kcalloc")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
---
 drivers/net/ethernet/broadcom/sb1250-mac.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/sb1250-mac.c b/drivers/net/ethernet/broadcom/sb1250-mac.c
index 30865fe03eeb..e16a49e22488 100644
--- a/drivers/net/ethernet/broadcom/sb1250-mac.c
+++ b/drivers/net/ethernet/broadcom/sb1250-mac.c
@@ -625,6 +625,8 @@ static void sbdma_initctx(struct sbmacdma *d, struct sbmac_softc *s, int chan,
 	d->sbdma_dscrtable_unaligned = kcalloc(d->sbdma_maxdescr + 1,
 					       sizeof(*d->sbdma_dscrtable),
 					       GFP_KERNEL);
+	if (!d->sbdma_dscrtable_unaligned)
+		return;		/* avoid NULL deref in ALIGN/phys conversion */
 
 	/*
 	 * The descriptor table must be aligned to at least 16 bytes or the
@@ -644,7 +646,11 @@ static void sbdma_initctx(struct sbmacdma *d, struct sbmac_softc *s, int chan,
 
 	d->sbdma_ctxtable = kcalloc(d->sbdma_maxdescr,
 				    sizeof(*d->sbdma_ctxtable), GFP_KERNEL);
-
+	if (!d->sbdma_ctxtable) {
+		kfree(d->sbdma_dscrtable_unaligned);
+		d->sbdma_dscrtable_unaligned = NULL;
+		return;
+	}
 #ifdef CONFIG_SBMAC_COALESCE
 	/*
 	 * Setup Rx/Tx DMA coalescing defaults
-- 
2.43.0