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Fix integer overflows. Will not work on compilers with unsigned char
as the default.
Fetched from: https://sources.debian.org/patches/libb64/1.2-5/
Combined "integer overflows.diff" and "off by one.diff" and adapted
for version 1.2.1.
Signed-off-by: Mikael Eliasson <mikael@robomagi.com>
diff --git a/src/cdecode.c b/src/cdecode.c
index a6c0a42..45da4e1 100644
--- a/src/cdecode.c
+++ b/src/cdecode.c
@@ -9,10 +9,11 @@ For details, see http://sourceforge.net/projects/libb64
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_in, const int length_in, char* plaintex
{
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_in, const int length_in, char* plaintex
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_in, const int length_in, char* plaintex
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_in, const int length_in, char* plaintex
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_in, const int length_in, char* plaintex
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);
}
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