Changeset 3401 for trunk/src/libopensc/asn1.c

Timestamp:

02/29/08 15:37:46 (11 months ago)

Author:

ludovic.rousseau

Message:

sc_asn1_decode_integer/asn1_encode_integer: correctly manage negative
numbers and some positive numbers like 128

Files:

• trunk/src/libopensc/asn1.c (modified) (3 diffs)

trunk/src/libopensc/asn1.c

@@ -534 +534 @@
         if (inlen > sizeof(int))
                 return SC_ERROR_INVALID_ASN1_OBJECT;
+        if (inbuf[0] & 0x80)
+                a = -1;
         for (i = 0; i < inlen; i++) {
                 a <<= 8;
@@ -544 +546 @@
 static int asn1_encode_integer(int in, u8 ** obj, size_t * objsize)
 {
-        int i = sizeof(in) * 8, skip = 1;
+        int i = sizeof(in) * 8, skip_zero, skip_sign;
         u8 *p, b;
 
-        *obj = p = (u8 *) malloc(sizeof(in));
+        if (in < 0)
+        {
+                skip_sign = 1;
+                skip_zero= 0;
+        }
+        else
+        {
+                skip_sign = 0;
+                skip_zero= 1;
+        }
+        *obj = p = (u8 *) malloc(sizeof(in)+1);
         if (*obj == NULL)
                 return SC_ERROR_OUT_OF_MEMORY;
@@ -553 +565 @@
                 i -= 8;
                 b = in >> i;
-                if (b == 0 && skip)
+                if (skip_sign)
+                {
+                        if (b != 0xff)
+                                skip_sign = 0;
+                        if (b & 0x80)
+                        {
+                                *p = b;
+                                if (0xff == b)
+                                        continue;
+                        }
+                        else
+                        {
+                                p++;
+                                skip_sign = 0;
+                        }
+                }
+                if (b == 0 && skip_zero)
                         continue;
-                skip = 0;
+                if (skip_zero) {
+                        skip_zero = 0;
+                        /* prepend 0x00 if MSb is 1 and integer positive */
+                        if ((b & 0x80) != 0 && in > 0)
+                                *p++ = 0;
+                }
                 *p++ = b;
         } while (i > 0);
+        if (skip_sign)
+                p++;
         *objsize = p - *obj;
         if (*objsize == 0) {