[PATCH v4 5/9] crypto: stm32/cryp - check early input data

[Nicolas Toromanoff]

Some auto tests failed because driver wasn't returning the expected
error with some input size/iv value/tag size.
Now:
 Return 0 early for empty buffer. (We don't need to start the engine for
 an empty input buffer).
 Accept any valid authsize for gcm(aes).
 Return -EINVAL if iv for ccm(aes) is invalid.
 Return -EINVAL if buffer size is a not a multiple of algorithm block size.

Fixes: 9e054ec21ef8 ("crypto: stm32 - Support for STM32 CRYP crypto module")

Signed-off-by: Nicolas Toromanoff <nicolas.toromanoff at foss.st.com>
---
 drivers/crypto/stm32/stm32-cryp.c | 114 +++++++++++++++++++++++++++++-
 1 file changed, 113 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/stm32/stm32-cryp.c b/drivers/crypto/stm32/stm32-cryp.c
index b2b553651964..06c03db0d11b 100644
--- a/drivers/crypto/stm32/stm32-cryp.c
+++ b/drivers/crypto/stm32/stm32-cryp.c
@@ -799,7 +799,20 @@ static int stm32_cryp_aes_aead_setkey(struct crypto_aead *tfm, const u8 *key,
 static int stm32_cryp_aes_gcm_setauthsize(struct crypto_aead *tfm,
 					  unsigned int authsize)
 {
-	return authsize == AES_BLOCK_SIZE ? 0 : -EINVAL;
+	switch (authsize) {
+	case 4:
+	case 8:
+	case 12:
+	case 13:
+	case 14:
+	case 15:
+	case 16:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
 }
 
 static int stm32_cryp_aes_ccm_setauthsize(struct crypto_aead *tfm,
@@ -823,31 +836,61 @@ static int stm32_cryp_aes_ccm_setauthsize(struct crypto_aead *tfm,
 
 static int stm32_cryp_aes_ecb_encrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % AES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_AES | FLG_ECB | FLG_ENCRYPT);
 }
 
 static int stm32_cryp_aes_ecb_decrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % AES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_AES | FLG_ECB);
 }
 
 static int stm32_cryp_aes_cbc_encrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % AES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_AES | FLG_CBC | FLG_ENCRYPT);
 }
 
 static int stm32_cryp_aes_cbc_decrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % AES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_AES | FLG_CBC);
 }
 
 static int stm32_cryp_aes_ctr_encrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_AES | FLG_CTR | FLG_ENCRYPT);
 }
 
 static int stm32_cryp_aes_ctr_decrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_AES | FLG_CTR);
 }
 
@@ -861,53 +904,122 @@ static int stm32_cryp_aes_gcm_decrypt(struct aead_request *req)
 	return stm32_cryp_aead_crypt(req, FLG_AES | FLG_GCM);
 }
 
+static inline int crypto_ccm_check_iv(const u8 *iv)
+{
+	/* 2 <= L <= 8, so 1 <= L' <= 7. */
+	if (iv[0] < 1 || iv[0] > 7)
+		return -EINVAL;
+
+	return 0;
+}
+
 static int stm32_cryp_aes_ccm_encrypt(struct aead_request *req)
 {
+	int err;
+
+	err = crypto_ccm_check_iv(req->iv);
+	if (err)
+		return err;
+
 	return stm32_cryp_aead_crypt(req, FLG_AES | FLG_CCM | FLG_ENCRYPT);
 }
 
 static int stm32_cryp_aes_ccm_decrypt(struct aead_request *req)
 {
+	int err;
+
+	err = crypto_ccm_check_iv(req->iv);
+	if (err)
+		return err;
+
 	return stm32_cryp_aead_crypt(req, FLG_AES | FLG_CCM);
 }
 
 static int stm32_cryp_des_ecb_encrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % DES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_DES | FLG_ECB | FLG_ENCRYPT);
 }
 
 static int stm32_cryp_des_ecb_decrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % DES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_DES | FLG_ECB);
 }
 
 static int stm32_cryp_des_cbc_encrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % DES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_DES | FLG_CBC | FLG_ENCRYPT);
 }
 
 static int stm32_cryp_des_cbc_decrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % DES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_DES | FLG_CBC);
 }
 
 static int stm32_cryp_tdes_ecb_encrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % DES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_TDES | FLG_ECB | FLG_ENCRYPT);
 }
 
 static int stm32_cryp_tdes_ecb_decrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % DES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_TDES | FLG_ECB);
 }
 
 static int stm32_cryp_tdes_cbc_encrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % DES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_TDES | FLG_CBC | FLG_ENCRYPT);
 }
 
 static int stm32_cryp_tdes_cbc_decrypt(struct skcipher_request *req)
 {
+	if (req->cryptlen % DES_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (req->cryptlen == 0)
+		return 0;
+
 	return stm32_cryp_crypt(req, FLG_TDES | FLG_CBC);
 }
 
-- 
2.17.1