[PATCH] crypto: iaa - Fix out-of-bounds index in find_empty_iaa_compression_mode

[Thorsten Blum]

The local variable 'i' is initialized with -EINVAL, but the for loop
immediately overwrites it and -EINVAL is never returned.

If no empty compression mode can be found, the function would return the
out-of-bounds index IAA_COMP_MODES_MAX, which would cause an invalid
array access in add_iaa_compression_mode().

Fix both issues by returning either a valid index or -EINVAL.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: b190447e0fa3 ("crypto: iaa - Add compression mode management along with fixed mode")
Signed-off-by: Thorsten Blum <thorsten.blum@xxxxxxxxx>
---
 drivers/crypto/intel/iaa/iaa_crypto_main.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/crypto/intel/iaa/iaa_crypto_main.c b/drivers/crypto/intel/iaa/iaa_crypto_main.c
index 23f585219fb4..8ee2a55ec449 100644
--- a/drivers/crypto/intel/iaa/iaa_crypto_main.c
+++ b/drivers/crypto/intel/iaa/iaa_crypto_main.c
@@ -221,15 +221,13 @@ static struct iaa_compression_mode *iaa_compression_modes[IAA_COMP_MODES_MAX];
 
 static int find_empty_iaa_compression_mode(void)
 {
-	int i = -EINVAL;
+	int i;
 
-	for (i = 0; i < IAA_COMP_MODES_MAX; i++) {
-		if (iaa_compression_modes[i])
-			continue;
-		break;
-	}
+	for (i = 0; i < IAA_COMP_MODES_MAX; i++)
+		if (!iaa_compression_modes[i])
+			return i;
 
-	return i;
+	return -EINVAL;
 }
 
 static struct iaa_compression_mode *find_iaa_compression_mode(const char *name, int *idx)
-- 
Thorsten Blum <thorsten.blum@xxxxxxxxx>
GPG: 1D60 735E 8AEF 3BE4 73B6  9D84 7336 78FD 8DFE EAD4