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make cram() sane

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- don't silently fail in release mode (expression with side effects
  inside assert())
- save some redundand strlen()s by not throwing away known lengths
- reorganize the code for legibility
This commit is contained in:
Oswald Buddenhagen 2011-01-23 13:35:56 +01:00
parent 058d01f179
commit 7e1c16ae02
1 changed files with 26 additions and 31 deletions
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57
src/drv_imap.c
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@ -1223,49 +1223,45 @@ hexchar( unsigned int b )
return 'a' + (b - 10);
}
/* XXX merge into do_cram_auth? */
static char *
cram( const char *challenge, const char *user, const char *pass )
static void
cram( const char *challenge, const char *user, const char *pass, char **_final, int *_finallen )
{
unsigned char *response, *final;
unsigned hashlen;
int i, clen, rlen, blen, flen, olen;
unsigned char hash[16];
char buf[256], hex[33];
HMAC_CTX hmac;
char hash[16];
char hex[33];
int i;
unsigned int hashlen = sizeof(hash);
char buf[256];
int len = strlen( challenge );
char *response = nfcalloc( 1 + len );
char *final;
/* response will always be smaller than challenge because we are
* decoding.
*/
len = EVP_DecodeBlock( (unsigned char *)response, (unsigned char *)challenge, strlen( challenge ) );
HMAC_Init( &hmac, (unsigned char *) pass, strlen( pass ), EVP_md5() );
HMAC_Update( &hmac, (unsigned char *)response, strlen( response ) );
HMAC_Final( &hmac, (unsigned char *)hash, &hashlen );
assert( hashlen == sizeof(hash) );
HMAC_Init( &hmac, (unsigned char *)pass, strlen( pass ), EVP_md5() );
clen = strlen( challenge );
/* response will always be smaller than challenge because we are decoding. */
response = nfcalloc( 1 + clen );
rlen = EVP_DecodeBlock( response, (unsigned char *)challenge, clen );
HMAC_Update( &hmac, response, rlen );
free( response );
hashlen = sizeof(hash);
HMAC_Final( &hmac, hash, &hashlen );
assert( hashlen == sizeof(hash) );
hex[32] = 0;
for (i = 0; i < 16; i++) {
hex[2 * i] = hexchar( (hash[i] >> 4) & 0xf );
hex[2 * i + 1] = hexchar( hash[i] & 0xf );
}
nfsnprintf( buf, sizeof(buf), "%s %s", user, hex );
blen = nfsnprintf( buf, sizeof(buf), "%s %s", user, hex );
len = strlen( buf );
len = ENCODED_SIZE( len ) + 1;
final = nfmalloc( len );
final[len - 1] = 0;
flen = ENCODED_SIZE( blen );
final = nfmalloc( flen + 1 );
final[flen] = 0;
olen = EVP_EncodeBlock( (unsigned char *)final, (unsigned char *)buf, blen );
assert( olen == flen );
assert( EVP_EncodeBlock( (unsigned char *)final, (unsigned char *)buf, strlen( buf ) ) == len - 1 );
return final;
*_final = (char *)final;
*_finallen = flen;
}
static int
@ -1275,11 +1271,10 @@ do_cram_auth( imap_store_t *ctx, struct imap_cmd *cmdp, const char *prompt )
char *resp;
int n, l;
resp = cram( prompt, srvc->user, srvc->pass );
cram( prompt, srvc->user, srvc->pass, &resp, &l );
if (DFlags & VERBOSE)
printf( ">+> %s\n", resp );
l = strlen( resp );
n = socket_write( &ctx->buf.sock, resp, l );
free( resp );
if (n != l)