[PATCH review for 4.9 46/50] s390/crypto: Extend key length check for AES-XTS in fips mode.

[Levin, Alexander (Sasha Levin)]

From: Harald Freudenberger <freude@xxxxxxxxxxxxxxxxxx>

[ Upstream commit a4f2779ecf2f42b0997fedef6fd20a931c40a3e3 ]

In fips mode only xts keys with 128 bit or 125 bit are allowed.
This fix extends the xts_aes_set_key function to check for these
valid key lengths in fips mode.

Signed-off-by: Harald Freudenberger <freude@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
 arch/s390/crypto/aes_s390.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
index 303d28eb03a2..591cbdf615af 100644
--- a/arch/s390/crypto/aes_s390.c
+++ b/arch/s390/crypto/aes_s390.c
@@ -28,6 +28,7 @@
 #include <linux/cpufeature.h>
 #include <linux/init.h>
 #include <linux/spinlock.h>
+#include <linux/fips.h>
 #include <crypto/xts.h>
 #include <asm/cpacf.h>
 
@@ -501,6 +502,12 @@ static int xts_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 	if (err)
 		return err;
 
+	/* In fips mode only 128 bit or 256 bit keys are valid */
+	if (fips_enabled && key_len != 32 && key_len != 64) {
+		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+
 	/* Pick the correct function code based on the key length */
 	fc = (key_len == 32) ? CPACF_KM_XTS_128 :
 	     (key_len == 64) ? CPACF_KM_XTS_256 : 0;
-- 
2.11.0