diff options
Diffstat (limited to 'base64.c')
| -rw-r--r-- | base64.c | 11 |
1 files changed, 8 insertions, 3 deletions
@@ -54,6 +54,7 @@ void to64frombits(unsigned char *out, const unsigned char *in, int inlen) int from64tobits(char *out, const char *in, int maxlen) /* base 64 to raw bytes in quasi-big-endian order, returning count of bytes */ +/* maxlen limits output buffer size, set to zero to ignore */ { int len = 0; register unsigned char digit1, digit2, digit3, digit4; @@ -78,17 +79,21 @@ int from64tobits(char *out, const char *in, int maxlen) return(-1); in += 4; ++len; - if (len && len >= maxlen) /* prevent buffer overflow */ + if (maxlen && len > maxlen) return(-1); *out++ = (DECODE64(digit1) << 2) | (DECODE64(digit2) >> 4); if (digit3 != '=') { - *out++ = ((DECODE64(digit2) << 4) & 0xf0) | (DECODE64(digit3) >> 2); ++len; + if (maxlen && len > maxlen) + return(-1); + *out++ = ((DECODE64(digit2) << 4) & 0xf0) | (DECODE64(digit3) >> 2); if (digit4 != '=') { + ++len; + if (maxlen && len > maxlen) + return(-1); *out++ = ((DECODE64(digit3) << 6) & 0xc0) | DECODE64(digit4); - ++len; } } } while |