Description: fix integer overflows

Author: Jakub Wilk <jwilk@debian.org>

Bug: http://sourceforge.net/tracker/?func=detail&aid=3591129&group_id=152942&atid=785907

Last-Update: 2012-11-30

Index: libb64-1.2.1/src/cdecode.c

===================================================================

--- libb64-1.2.1.orig/src/cdecode.c

+++ libb64-1.2.1/src/cdecode.c

@@ -9,10 +9,11 @@ For details, see http://sourceforge.net/

 int base64_decode_value(char value_in)

 {

-	static const char decoding[] = {62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51};

+	static const signed char decoding[] = {62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51};

 	static const char decoding_size = sizeof(decoding);

+	if (value_in < 43) return -1;

 	value_in -= 43;

-	if (value_in < 0 || value_in >= decoding_size) return -1;

+	if (value_in > decoding_size) return -1;

 	return decoding[(int)value_in];

 }

@@ -26,7 +27,7 @@ int base64_decode_block(const char* code

 {

 	const char* codechar = code_in;

 	char* plainchar = plaintext_out;

-	char fragment;

+	int fragment;

 	*plainchar = state_in->plainchar;

@@ -42,7 +43,7 @@ int base64_decode_block(const char* code

 					state_in->plainchar = *plainchar;

 					return plainchar - plaintext_out;

 				}

-				fragment = (char)base64_decode_value(*codechar++);

+				fragment = base64_decode_value(*codechar++);

 			} while (fragment < 0);

 			*plainchar    = (fragment & 0x03f) << 2;

 	case step_b:

@@ -53,7 +54,7 @@ int base64_decode_block(const char* code

 					state_in->plainchar = *plainchar;

 					return plainchar - plaintext_out;

 				}

-				fragment = (char)base64_decode_value(*codechar++);

+				fragment = base64_decode_value(*codechar++);

 			} while (fragment < 0);

 			*plainchar++ |= (fragment & 0x030) >> 4;

 			*plainchar    = (fragment & 0x00f) << 4;

@@ -65,7 +66,7 @@ int base64_decode_block(const char* code

 					state_in->plainchar = *plainchar;

 					return plainchar - plaintext_out;

 				}

-				fragment = (char)base64_decode_value(*codechar++);

+				fragment = base64_decode_value(*codechar++);

 			} while (fragment < 0);

 			*plainchar++ |= (fragment & 0x03c) >> 2;

 			*plainchar    = (fragment & 0x003) << 6;

@@ -77,7 +78,7 @@ int base64_decode_block(const char* code

 					state_in->plainchar = *plainchar;

 					return plainchar - plaintext_out;

 				}

-				fragment = (char)base64_decode_value(*codechar++);

+				fragment = base64_decode_value(*codechar++);

 			} while (fragment < 0);

 			*plainchar++   |= (fragment & 0x03f);

 		}