Commit f3ee5877 authored by Steve Holme's avatar Steve Holme
Browse files

base64: Post extended extended validation tidy up 

Reduced the separate processing of the last quantum to be performed in
the main decoding loop and renamed some variables for consistency.
parent c92c30ed

lib/base64.c

+19 −28
Original line number Diff line number Diff line
@@ -68,9 +68,13 @@ static size_t decodeQuantum(unsigned char *dest, const char *src) 
    }

  }



  if(padding < 2)

    dest[2] = curlx_ultouc(x & 0xFFUL);



  x >>= 8;

  if(padding < 1)

    dest[1] = curlx_ultouc(x & 0xFFUL);



  x >>= 8;

  dest[0] = curlx_ultouc(x & 0xFFUL);
@@ -94,23 +98,22 @@ static size_t decodeQuantum(unsigned char *dest, const char *src) 
CURLcode Curl_base64_decode(const char *src,

                            unsigned char **outptr, size_t *outlen)

{

  size_t srcLen = 0;

  size_t srclen = 0;

  size_t length = 0;

  size_t equalsTerm = 0;

  size_t padding = 0;

  size_t i;

  size_t result;

  size_t numQuantums;

  unsigned char lastQuantum[3];

  size_t rawlen = 0;

  unsigned char *pos;

  unsigned char *newstr;



  *outptr = NULL;

  *outlen = 0;

  srcLen = strlen(src);

  srclen = strlen(src);



  /* Check the length of the input string is valid */

  if(!srcLen || srcLen % 4)

  if(!srclen || srclen % 4)

    return CURLE_BAD_CONTENT_ENCODING;



  /* Find the position of any = padding characters */
@@ -119,20 +122,20 @@ CURLcode Curl_base64_decode(const char *src, 


  /* A maximum of two = padding characters is allowed */

  if(src[length] == '=') {

    equalsTerm++;

    if(src[length+equalsTerm] == '=')

      equalsTerm++;

    padding++;

    if(src[length + 1] == '=')

      padding++;

  }



  /* Check the = padding characters weren't part way through the input */

  if(length + equalsTerm != srcLen)

  if(length + padding != srclen)

    return CURLE_BAD_CONTENT_ENCODING;



  /* Calculate the number of quantums */

  numQuantums = srcLen / 4;

  numQuantums = srclen / 4;



  /* Calculate the size of the decoded string */

  rawlen = (numQuantums * 3) - equalsTerm;

  rawlen = (numQuantums * 3) - padding;



  /* Allocate our buffer including room for a zero terminator */

  newstr = malloc(rawlen + 1);
@@ -141,9 +144,8 @@ CURLcode Curl_base64_decode(const char *src, 


  pos = newstr;



  /* Decode all but the last quantum (which may not decode to a

  multiple of 3 bytes) */

  for(i = 0; i < numQuantums - 1; i++) {

  /* Decode the quantums */

  for(i = 0; i < numQuantums; i++) {

    result = decodeQuantum(pos, src);

    if(!result) {

      Curl_safefree(newstr);
@@ -155,19 +157,8 @@ CURLcode Curl_base64_decode(const char *src, 
    src += 4;

  }



  /* Decode the last quantum */

  result = decodeQuantum(lastQuantum, src);

  if(!result) {

    Curl_safefree(newstr);



    return CURLE_BAD_CONTENT_ENCODING;

  }



  for(i = 0; i < 3 - equalsTerm; i++)

    pos[i] = lastQuantum[i];



  /* Zero terminate */

  pos[i] = '\0';

  *pos = '\0';



  /* Return the decoded data */

  *outptr = newstr;