Use IV length of a crypter instead of block size for IV calculations

[strongswan.git] / src / libcharon / encoding / payloads / encryption_payload.c

diff --git a/src/libcharon/encoding/payloads/encryption_payload.c b/src/libcharon/encoding/payloads/encryption_payload.c
index 2adbb88..e31b438 100644 (file)
--- a/src/libcharon/encoding/payloads/encryption_payload.c
+++ b/src/libcharon/encoding/payloads/encryption_payload.c
@@ -199,7 +199,7 @@ static void compute_length(private_encryption_payload_t *this)
                block_size = this->crypter->get_block_size(this->crypter);
                length += block_size - length % block_size;
                /* add iv */
-               length += block_size;
+               length += this->crypter->get_iv_size(this->crypter);
                /* add signature */
                length += this->signer->get_block_size(this->signer);
        }
@@ -355,7 +355,7 @@ static status_t encrypt(private_encryption_payload_t *this)
        *(to_crypt.ptr + to_crypt.len - 1) = padding.len;
 
        /* build iv */
-       iv.len = block_size;
+       iv.len = this->crypter->get_iv_size(this->crypter);
        rng->allocate_bytes(rng, iv.len, &iv);
        rng->destroy(rng);
 
@@ -450,17 +450,22 @@ static status_t decrypt(private_encryption_payload_t *this)
        }
 
        /* get IV */
-       iv.len = this->crypter->get_block_size(this->crypter);
-
+       iv.len = this->crypter->get_iv_size(this->crypter);
+       if (iv.len > this->encrypted.len)
+       {
+               DBG1(DBG_ENC, "could not decrypt, input too short");
+               return FAILED;
+       }
        iv.ptr = this->encrypted.ptr;
 
-       /* point concatenated to data + padding + padding_length*/
+       /* point concatenated to data + padding + padding_length */
        concatenated.ptr = this->encrypted.ptr + iv.len;
        concatenated.len = this->encrypted.len - iv.len -
                                                                this->signer->get_block_size(this->signer);
 
        /* concatenated must be a multiple of block_size of crypter */
-       if (concatenated.len < iv.len || concatenated.len % iv.len)
+       if (concatenated.len < iv.len ||
+               concatenated.len % this->crypter->get_block_size(this->crypter))
        {
                DBG1(DBG_ENC, "could not decrypt, invalid input");
                return FAILED;