diff options
| -rw-r--r-- | libbb/uuencode.c | 100 | ||||
| -rw-r--r-- | networking/httpd.c | 37 |
2 files changed, 36 insertions, 101 deletions
diff --git a/libbb/uuencode.c b/libbb/uuencode.c index b4ee20c20..2e9edb219 100644 --- a/libbb/uuencode.c +++ b/libbb/uuencode.c @@ -82,7 +82,7 @@ void FAST_FUNC bb_uuencode(char *p, const void *src, int length, const char *tbl } /* - * Decode base64 encoded string. Stops on '\0'. + * Decode base64 encoded string. Stops on NUL after terminating "=" or "==". * * Returns: pointer to the undecoded part of source. * If points to '\0', then the source was fully decoded. @@ -91,76 +91,48 @@ void FAST_FUNC bb_uuencode(char *p, const void *src, int length, const char *tbl const char* FAST_FUNC decode_base64(char **pp_dst, const char *src) { char *dst = *pp_dst; - const char *src_tail; - - while (1) { - unsigned char six_bit[4]; - int count = 0; + unsigned ch = 0; + int i = 0; - /* Fetch up to four 6-bit values */ - src_tail = src; - while (count < 4) { - char *table_ptr; - int ch; + while (*src) { + int t = (unsigned char)*src++; - /* Get next _valid_ character. - * bb_uuenc_tbl_base64[] contains this string: - * 0 1 2 3 4 5 6 - * 01234567890123456789012345678901234567890123456789012345678901234 - * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=" - */ - do { - ch = *src; - if (ch == '\0') { - if (count == 0) { - /* Example: - * If we decode "QUJD <NUL>", we want - * to return ptr to NUL, not to ' ', - * because we did fully decode - * the string (to "ABC"). - */ - src_tail = src; - } - goto ret; - } - src++; - table_ptr = strchr(bb_uuenc_tbl_base64, ch); + /* "if" forest is faster than strchr(bb_uuenc_tbl_base64, t) */ + if (t >= '0' && t <= '9') + t = t - '0' + 52; + else if (t >= 'A' && t <= 'Z') + t = t - 'A'; + else if (t >= 'a' && t <= 'z') + t = t - 'a' + 26; + else if (t == '+') + t = 62; + else if (t == '/') + t = 63; + else if (t == '=' && (i == 3 || (i == 2 && *src == '='))) + /* the above disallows "==AA", "A===", "AA=A" etc */ + t = 0x1000000; + else //TODO: add BASE64_FLAG_foo to die on bad char? - } while (!table_ptr); - - /* Convert encoded character to decimal */ - ch = table_ptr - bb_uuenc_tbl_base64; + continue; - /* ch is 64 if char was '=', otherwise 0..63 */ - if (ch == 64) + ch = (ch << 6) | t; + if (++i == 4) { + *dst++ = (char) (ch >> 16); + *dst++ = (char) (ch >> 8); + *dst++ = (char) ch; + i = 0; + if (ch & 0x1000000) { /* was last input char '='? */ + dst--; + if (ch & (0x1000000 << 6)) /* was it "=="? */ + dst--; break; - six_bit[count] = ch; - count++; + } + ch = 0; } - - /* Transform 6-bit values to 8-bit ones. - * count can be < 4 when we decode the tail: - * "eQ==" -> "y", not "y NUL NUL". - * Note that (count > 1) is always true, - * "x===" encoding is not valid: - * even a single zero byte encodes as "AA==". - * However, with current logic we come here with count == 1 - * when we decode "==" tail. - */ - if (count > 1) - *dst++ = six_bit[0] << 2 | six_bit[1] >> 4; - if (count > 2) - *dst++ = six_bit[1] << 4 | six_bit[2] >> 2; - if (count > 3) - *dst++ = six_bit[2] << 6 | six_bit[3]; - /* Note that if we decode "AA==" and ate first '=', - * we just decoded one char (count == 2) and now we'll - * do the loop once more to decode second '='. - */ - } /* while (1) */ - ret: + } *pp_dst = dst; - return src_tail; + /* i should be zero here if full 4-char block was decoded */ + return src - i; /* -i rejects truncations: e.g. "MQ" and "MQ=" (correct encoding is "MQ==" -> "1") */ } #if ENABLE_BASE32 diff --git a/networking/httpd.c b/networking/httpd.c index 961f8cab4..4ffd89c48 100644 --- a/networking/httpd.c +++ b/networking/httpd.c @@ -1017,46 +1017,9 @@ static char *encodeString(const char *string) */ static void decodeBase64(char *Data) { -# if ENABLE_BASE64 || ENABLE_UUDECODE - /* Call decode_base64() from uuencode.c */ char *eptr = Data; decode_base64(&eptr, Data); *eptr = '\0'; -# else - const unsigned char *in = (const unsigned char *)Data; - /* The decoded size will be at most 3/4 the size of the encoded */ - unsigned ch = 0; - int i = 0; - - while (*in) { - int t = *in++; - - if (t >= '0' && t <= '9') - t = t - '0' + 52; - else if (t >= 'A' && t <= 'Z') - t = t - 'A'; - else if (t >= 'a' && t <= 'z') - t = t - 'a' + 26; - else if (t == '+') - t = 62; - else if (t == '/') - t = 63; - else if (t == '=') - t = 0; - else - continue; - - ch = (ch << 6) | t; - i++; - if (i == 4) { - *Data++ = (char) (ch >> 16); - *Data++ = (char) (ch >> 8); - *Data++ = (char) ch; - i = 0; - } - } - *Data = '\0'; -# endif } #endif |