pullup from 1.2 branch

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@12442 dc483132-0cff-0310-8789-dd5450dbe970

1 files changed, 18 insertions, 1 deletions

diff --git a/src/lib/crypto/old/old_decrypt.c b/src/lib/crypto/old/old_decrypt.c
index 1bcb0d38b..bfbe56a10 100644
--- a/src/lib/crypto/old/old_decrypt.c
+++ b/src/lib/crypto/old/old_decrypt.c
@@ -45,7 +45,7 @@ krb5_old_decrypt(enc, hash, key, usage, ivec, input, arg_output)
 {
     krb5_error_code ret;
     size_t blocksize, hashsize, plainsize;
-    unsigned char *cksumdata;
+    unsigned char *cksumdata, *cn;
     krb5_data output, cksum, crcivec;
     int alloced;
 
@@ -82,6 +82,17 @@ krb5_old_decrypt(enc, hash, key, usage, ivec, input, arg_output)
 
     /* decrypt it */
 
+    /* save last ciphertext block in case we decrypt in place */
+    if (ivec != NULL && ivec->length == blocksize) {
+	cn = malloc(blocksize);
+	if (cn == NULL) {
+	    ret = ENOMEM;
+	    goto cleanup;
+	}
+	memcpy(cn, input->data + input->length - blocksize, blocksize);
+    } else
+	cn = NULL;
+
     /* XXX this is gross, but I don't have much choice */
     if ((key->enctype == ENCTYPE_DES_CBC_CRC) && (ivec == 0)) {
 	crcivec.length = key->length;
@@ -119,6 +130,10 @@ krb5_old_decrypt(enc, hash, key, usage, ivec, input, arg_output)
     }
     arg_output->length = plainsize;
 
+    /* update ivec */
+    if (cn != NULL)
+	memcpy(ivec->data, cn, blocksize);
+
     ret = 0;
 
 cleanup:
@@ -127,6 +142,8 @@ cleanup:
 	free(output.data);
     }
 
+    if (cn != NULL)
+	free(cn);
     memset(cksumdata, 0, hashsize);
     free(cksumdata);
     return(ret);