openssl: move shared AES-CTR code into misc
diff --git a/src/misc.c b/src/misc.c
index f7faae7..94904ab 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -643,3 +643,31 @@
}
return p;
}
+
+/* XOR operation on buffers input1 and input2, result in output.
+ It is safe to use an input buffer as the output buffer. */
+void _libssh2_xor_data(unsigned char *output,
+ const unsigned char *input1,
+ const unsigned char *input2,
+ size_t length)
+{
+ size_t i;
+
+ for (i = 0; i < length; i++)
+ *output++ = *input1++ ^ *input2++;
+}
+
+/* Increments an AES CTR buffer to prepare it for use with the
+ next AES block. */
+void _libssh2_aes_ctr_increment(unsigned char *ctr,
+ size_t length)
+{
+ if (length == 0)
+ return;
+ size_t i = (length - 1);
+ while (ctr[i]++ == 0xFF) {
+ if (i == 0)
+ break;
+ i--;
+ }
+}
diff --git a/src/misc.h b/src/misc.h
index 54ae546..44e2996 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -93,4 +93,11 @@
#endif
#endif
+void _libssh2_xor_data(unsigned char *output,
+ const unsigned char *input1,
+ const unsigned char *input2,
+ size_t length);
+
+void _libssh2_aes_ctr_increment(unsigned char *ctr, size_t length);
+
#endif /* _LIBSSH2_MISC_H */
diff --git a/src/openssl.c b/src/openssl.c
index b7b146c..f10f292 100644
--- a/src/openssl.c
+++ b/src/openssl.c
@@ -43,6 +43,7 @@
#ifdef LIBSSH2_OPENSSL /* compile only if we build with openssl */
#include <string.h>
+#include "misc.h"
#ifndef EVP_MAX_BLOCK_LENGTH
#define EVP_MAX_BLOCK_LENGTH 32
@@ -364,15 +365,8 @@
return 0;
}
- for (i = 0; i < 16; i++)
- *out++ = *in++ ^ b1[i];
-
- i = 15;
- while (c->ctr[i]++ == 0xFF) {
- if (i == 0)
- break;
- i--;
- }
+ _libssh2_xor_data(out, in, b1, AES_BLOCK_SIZE);
+ _libssh2_aes_ctr_increment(c->ctr, AES_BLOCK_SIZE);
return 1;
}
