[PATCH 5/6] crypto: omap-aes-gcm - check length of assocdata in RFC4106 mode

[Ard Biesheuvel <ardb@kernel.org>]

RFC4106 requires the associated data to be a certain size, so reject
inputs that are wrong. This also prevents crashes or other problems due
to assoclen becoming negative after subtracting 8 bytes.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/crypto/omap-aes-gcm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/omap-aes-gcm.c b/drivers/crypto/omap-aes-gcm.c
index 70398fbd669d..1aabf9a72066 100644
--- a/drivers/crypto/omap-aes-gcm.c
+++ b/drivers/crypto/omap-aes-gcm.c
@@ -365,7 +365,8 @@ int omap_aes_4106gcm_encrypt(struct aead_request *req)
 
 	memcpy(rctx->iv, ctx->nonce, 4);
 	memcpy(rctx->iv + 4, req->iv, 8);
-	return omap_aes_gcm_crypt(req, FLAGS_ENCRYPT | FLAGS_GCM |
+	return crypto_ipsec_check_assoclen(req->assoclen) ?:
+	       omap_aes_gcm_crypt(req, FLAGS_ENCRYPT | FLAGS_GCM |
 				  FLAGS_RFC4106_GCM);
 }
 
@@ -376,7 +377,8 @@ int omap_aes_4106gcm_decrypt(struct aead_request *req)
 
 	memcpy(rctx->iv, ctx->nonce, 4);
 	memcpy(rctx->iv + 4, req->iv, 8);
-	return omap_aes_gcm_crypt(req, FLAGS_GCM | FLAGS_RFC4106_GCM);
+	return crypto_ipsec_check_assoclen(req->assoclen) ?:
+	       omap_aes_gcm_crypt(req, FLAGS_GCM | FLAGS_RFC4106_GCM);
 }
 
 int omap_aes_gcm_setkey(struct crypto_aead *tfm, const u8 *key,
-- 
2.17.1