Allow specifying the tag after AAD in CCM mode

[oweals/openssl.git] / crypto / evp / e_aes.c

diff --git a/crypto/evp/e_aes.c b/crypto/evp/e_aes.c
index 16ffe4d5562e15b6112c89570263c12afa02112d..6d8d4370a7bcdd49074c68a0a31a483d7286aacb 100644 (file)
--- a/crypto/evp/e_aes.c
+++ b/crypto/evp/e_aes.c
@@ -3792,8 +3792,6 @@ static int aes_ccm_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
     if (!cctx->iv_set)
         return -1;
 
-    if (!EVP_CIPHER_CTX_encrypting(ctx) && !cctx->tag_set)
-        return -1;
     if (!out) {
         if (!in) {
             if (CRYPTO_ccm128_setiv(ccm, EVP_CIPHER_CTX_iv_noconst(ctx),
@@ -3808,6 +3806,11 @@ static int aes_ccm_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
         CRYPTO_ccm128_aad(ccm, in, len);
         return len;
     }
+
+    /* The tag must be set before actually decrypting data */
+    if (!EVP_CIPHER_CTX_encrypting(ctx) && !cctx->tag_set)
+        return -1;
+
     /* If not set length yet do it */
     if (!cctx->len_set) {
         if (CRYPTO_ccm128_setiv(ccm, EVP_CIPHER_CTX_iv_noconst(ctx),