[PATCH 5.14 480/849] iwlwifi: pnvm: read EFI data only if long enough

[Greg Kroah-Hartman]

From: Johannes Berg <johannes.berg@xxxxxxxxx>

[ Upstream commit e864a77f51d0d8113b49cf7d030bc9dc911c8176 ]

If the data we get from EFI is not even long enough for
the package struct we expect then ignore it entirely.

Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Fixes: a1a6a4cf49ec ("iwlwifi: pnvm: implement reading PNVM from UEFI")
Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/iwlwifi.20211016114029.33feba783518.I54a5cf33975d0330792b3d208b225d479e168f32@changeid
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/wireless/intel/iwlwifi/fw/pnvm.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/pnvm.c b/drivers/net/wireless/intel/iwlwifi/fw/pnvm.c
index 512c512eefc71..24de6e5eb6a4c 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/pnvm.c
+++ b/drivers/net/wireless/intel/iwlwifi/fw/pnvm.c
@@ -284,9 +284,13 @@ int iwl_pnvm_load(struct iwl_trans *trans,
 	/* First attempt to get the PNVM from BIOS */
 	package = iwl_uefi_get_pnvm(trans, &len);
 	if (!IS_ERR_OR_NULL(package)) {
-		/* we need only the data */
-		len -= sizeof(*package);
-		data = kmemdup(package->data, len, GFP_KERNEL);
+		if (len >= sizeof(*package)) {
+			/* we need only the data */
+			len -= sizeof(*package);
+			data = kmemdup(package->data, len, GFP_KERNEL);
+		} else {
+			data = NULL;
+		}
 
 		/* free package regardless of whether kmemdup succeeded */
 		kfree(package);
-- 
2.33.0