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416ecc1584
curl/lib/http_digest.c
Daniel Stenberg 7f963a19ec checksrc: ban unsafe functions 
The list of unsafe functions currently consists of sprintf, vsprintf,
strcat, strncat and gets.

Subsequently, some existing code needed updating to avoid warnings on
this.
2013-03-07 11:08:05 +01:00

586 lines
16 KiB
C
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "curl_setup.h"
#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_CRYPTO_AUTH)
#include "urldata.h"
#include "sendf.h"
#include "rawstr.h"
#include "curl_base64.h"
#include "curl_md5.h"
#include "http_digest.h"
#include "strtok.h"
#include "url.h" /* for Curl_safefree() */
#include "curl_memory.h"
#include "non-ascii.h" /* included for Curl_convert_... prototypes */
#include "warnless.h"
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
/* The last #include file should be: */
#include "memdebug.h"
#define MAX_VALUE_LENGTH 256
#define MAX_CONTENT_LENGTH 1024
static void digest_cleanup_one(struct digestdata *dig);
/*
* Return 0 on success and then the buffers are filled in fine.
*
* Non-zero means failure to parse.
*/
static int get_pair(const char *str, char *value, char *content,
const char **endptr)
{
int c;
bool starts_with_quote = FALSE;
bool escape = FALSE;
for(c=MAX_VALUE_LENGTH-1; (*str && (*str != '=') && c--); )
*value++ = *str++;
*value=0;
if('=' != *str++)
/* eek, no match */
return 1;
if('\"' == *str) {
/* this starts with a quote so it must end with one as well! */
str++;
starts_with_quote = TRUE;
}
for(c=MAX_CONTENT_LENGTH-1; *str && c--; str++) {
switch(*str) {
case '\\':
if(!escape) {
/* possibly the start of an escaped quote */
escape = TRUE;
*content++ = '\\'; /* even though this is an escape character, we still
store it as-is in the target buffer */
continue;
}
break;
case ',':
if(!starts_with_quote) {
/* this signals the end of the content if we didn't get a starting
quote and then we do "sloppy" parsing */
c=0; /* the end */
continue;
}
break;
case '\r':
case '\n':
/* end of string */
c=0;
continue;
case '\"':
if(!escape && starts_with_quote) {
/* end of string */
c=0;
continue;
}
break;
}
escape = FALSE;
*content++ = *str;
}
*content=0;
*endptr = str;
return 0; /* all is fine! */
}
/* Test example headers:
WWW-Authenticate: Digest realm="testrealm", nonce="1053604598"
Proxy-Authenticate: Digest realm="testrealm", nonce="1053604598"
*/
CURLdigest Curl_input_digest(struct connectdata *conn,
bool proxy,
const char *header) /* rest of the *-authenticate:
header */
{
char *token = NULL;
char *tmp = NULL;
bool foundAuth = FALSE;
bool foundAuthInt = FALSE;
struct SessionHandle *data=conn->data;
bool before = FALSE; /* got a nonce before */
struct digestdata *d;
if(proxy) {
d = &data->state.proxydigest;
}
else {
d = &data->state.digest;
}
/* skip initial whitespaces */
while(*header && ISSPACE(*header))
header++;
if(checkprefix("Digest", header)) {
header += strlen("Digest");
/* If we already have received a nonce, keep that in mind */
if(d->nonce)
before = TRUE;
/* clear off any former leftovers and init to defaults */
digest_cleanup_one(d);
for(;;) {
char value[MAX_VALUE_LENGTH];
char content[MAX_CONTENT_LENGTH];
while(*header && ISSPACE(*header))
header++;
/* extract a value=content pair */
if(!get_pair(header, value, content, &header)) {
if(Curl_raw_equal(value, "nonce")) {
d->nonce = strdup(content);
if(!d->nonce)
return CURLDIGEST_NOMEM;
}
else if(Curl_raw_equal(value, "stale")) {
if(Curl_raw_equal(content, "true")) {
d->stale = TRUE;
d->nc = 1; /* we make a new nonce now */
}
}
else if(Curl_raw_equal(value, "realm")) {
d->realm = strdup(content);
if(!d->realm)
return CURLDIGEST_NOMEM;
}
else if(Curl_raw_equal(value, "opaque")) {
d->opaque = strdup(content);
if(!d->opaque)
return CURLDIGEST_NOMEM;
}
else if(Curl_raw_equal(value, "qop")) {
char *tok_buf;
/* tokenize the list and choose auth if possible, use a temporary
clone of the buffer since strtok_r() ruins it */
tmp = strdup(content);
if(!tmp)
return CURLDIGEST_NOMEM;
token = strtok_r(tmp, ",", &tok_buf);
while(token != NULL) {
if(Curl_raw_equal(token, "auth")) {
foundAuth = TRUE;
}
else if(Curl_raw_equal(token, "auth-int")) {
foundAuthInt = TRUE;
}
token = strtok_r(NULL, ",", &tok_buf);
}
free(tmp);
/*select only auth o auth-int. Otherwise, ignore*/
if(foundAuth) {
d->qop = strdup("auth");
if(!d->qop)
return CURLDIGEST_NOMEM;
}
else if(foundAuthInt) {
d->qop = strdup("auth-int");
if(!d->qop)
return CURLDIGEST_NOMEM;
}
}
else if(Curl_raw_equal(value, "algorithm")) {
d->algorithm = strdup(content);
if(!d->algorithm)
return CURLDIGEST_NOMEM;
if(Curl_raw_equal(content, "MD5-sess"))
d->algo = CURLDIGESTALGO_MD5SESS;
else if(Curl_raw_equal(content, "MD5"))
d->algo = CURLDIGESTALGO_MD5;
else
return CURLDIGEST_BADALGO;
}
else {
/* unknown specifier, ignore it! */
}
}
else
break; /* we're done here */
/* pass all additional spaces here */
while(*header && ISSPACE(*header))
header++;
if(',' == *header)
/* allow the list to be comma-separated */
header++;
}
/* We had a nonce since before, and we got another one now without
'stale=true'. This means we provided bad credentials in the previous
request */
if(before && !d->stale)
return CURLDIGEST_BAD;
/* We got this header without a nonce, that's a bad Digest line! */
if(!d->nonce)
return CURLDIGEST_BAD;
}
else
/* else not a digest, get out */
return CURLDIGEST_NONE;
return CURLDIGEST_FINE;
}
/* convert md5 chunk to RFC2617 (section 3.1.3) -suitable ascii string*/
static void md5_to_ascii(unsigned char *source, /* 16 bytes */
unsigned char *dest) /* 33 bytes */
{
int i;
for(i=0; i<16; i++)
snprintf((char *)&dest[i*2], 3, "%02x", source[i]);
}
CURLcode Curl_output_digest(struct connectdata *conn,
bool proxy,
const unsigned char *request,
const unsigned char *uripath)
{
/* We have a Digest setup for this, use it! Now, to get all the details for
this sorted out, I must urge you dear friend to read up on the RFC2617
section 3.2.2, */
unsigned char md5buf[16]; /* 16 bytes/128 bits */
unsigned char request_digest[33];
unsigned char *md5this;
unsigned char *ha1;
unsigned char ha2[33];/* 32 digits and 1 zero byte */
char cnoncebuf[33];
char *cnonce = NULL;
size_t cnonce_sz = 0;
char *tmp = NULL;
struct timeval now;
char **allocuserpwd;
size_t userlen;
const char *userp;
const char *passwdp;
struct auth *authp;
struct SessionHandle *data = conn->data;
struct digestdata *d;
CURLcode rc;
/* The CURL_OUTPUT_DIGEST_CONV macro below is for non-ASCII machines.
It converts digest text to ASCII so the MD5 will be correct for
what ultimately goes over the network.
*/
#define CURL_OUTPUT_DIGEST_CONV(a, b) \
rc = Curl_convert_to_network(a, (char *)b, strlen((const char*)b)); \
if(rc != CURLE_OK) { \
free(b); \
return rc; \
}
if(proxy) {
d = &data->state.proxydigest;
allocuserpwd = &conn->allocptr.proxyuserpwd;
userp = conn->proxyuser;
passwdp = conn->proxypasswd;
authp = &data->state.authproxy;
}
else {
d = &data->state.digest;
allocuserpwd = &conn->allocptr.userpwd;
userp = conn->user;
passwdp = conn->passwd;
authp = &data->state.authhost;
}
if(*allocuserpwd) {
Curl_safefree(*allocuserpwd);
*allocuserpwd = NULL;
}
/* not set means empty */
if(!userp)
userp="";
if(!passwdp)
passwdp="";
if(!d->nonce) {
authp->done = FALSE;
return CURLE_OK;
}
authp->done = TRUE;
if(!d->nc)
d->nc = 1;
if(!d->cnonce) {
/* Generate a cnonce */
now = Curl_tvnow();
snprintf(cnoncebuf, sizeof(cnoncebuf), "%32ld",
(long)now.tv_sec + now.tv_usec);
rc = Curl_base64_encode(data, cnoncebuf, strlen(cnoncebuf),
&cnonce, &cnonce_sz);
if(rc)
return rc;
d->cnonce = cnonce;
}
/*
if the algorithm is "MD5" or unspecified (which then defaults to MD5):
A1 = unq(username-value) ":" unq(realm-value) ":" passwd
if the algorithm is "MD5-sess" then:
A1 = H( unq(username-value) ":" unq(realm-value) ":" passwd )
":" unq(nonce-value) ":" unq(cnonce-value)
*/
md5this = (unsigned char *)
aprintf("%s:%s:%s", userp, d->realm, passwdp);
if(!md5this)
return CURLE_OUT_OF_MEMORY;
CURL_OUTPUT_DIGEST_CONV(data, md5this); /* convert on non-ASCII machines */
Curl_md5it(md5buf, md5this);
free(md5this); /* free this again */
ha1 = malloc(33); /* 32 digits and 1 zero byte */
if(!ha1)
return CURLE_OUT_OF_MEMORY;
md5_to_ascii(md5buf, ha1);
if(d->algo == CURLDIGESTALGO_MD5SESS) {
/* nonce and cnonce are OUTSIDE the hash */
tmp = aprintf("%s:%s:%s", ha1, d->nonce, d->cnonce);
if(!tmp)
return CURLE_OUT_OF_MEMORY;
CURL_OUTPUT_DIGEST_CONV(data, tmp); /* convert on non-ASCII machines */
Curl_md5it(md5buf, (unsigned char *)tmp);
free(tmp); /* free this again */
md5_to_ascii(md5buf, ha1);
}
/*
If the "qop" directive's value is "auth" or is unspecified, then A2 is:
A2 = Method ":" digest-uri-value
If the "qop" value is "auth-int", then A2 is:
A2 = Method ":" digest-uri-value ":" H(entity-body)
(The "Method" value is the HTTP request method as specified in section
5.1.1 of RFC 2616)
*/
/* So IE browsers < v7 cut off the URI part at the query part when they
evaluate the MD5 and some (IIS?) servers work with them so we may need to
do the Digest IE-style. Note that the different ways cause different MD5
sums to get sent.
Apache servers can be set to do the Digest IE-style automatically using
the BrowserMatch feature:
http://httpd.apache.org/docs/2.2/mod/mod_auth_digest.html#msie
Further details on Digest implementation differences:
http://www.fngtps.com/2006/09/http-authentication
*/
if(authp->iestyle && ((tmp = strchr((char *)uripath, '?')) != NULL)) {
md5this = (unsigned char *)aprintf("%s:%.*s", request,
curlx_sztosi(tmp - (char *)uripath),
uripath);
}
else
md5this = (unsigned char *)aprintf("%s:%s", request, uripath);
if(!md5this) {
free(ha1);
return CURLE_OUT_OF_MEMORY;
}
if(d->qop && Curl_raw_equal(d->qop, "auth-int")) {
/* We don't support auth-int at the moment. I can't see a easy way to get
entity-body here */
/* TODO: Append H(entity-body)*/
}
CURL_OUTPUT_DIGEST_CONV(data, md5this); /* convert on non-ASCII machines */
Curl_md5it(md5buf, md5this);
free(md5this); /* free this again */
md5_to_ascii(md5buf, ha2);
if(d->qop) {
md5this = (unsigned char *)aprintf("%s:%s:%08x:%s:%s:%s",
ha1,
d->nonce,
d->nc,
d->cnonce,
d->qop,
ha2);
}
else {
md5this = (unsigned char *)aprintf("%s:%s:%s",
ha1,
d->nonce,
ha2);
}
free(ha1);
if(!md5this)
return CURLE_OUT_OF_MEMORY;
CURL_OUTPUT_DIGEST_CONV(data, md5this); /* convert on non-ASCII machines */
Curl_md5it(md5buf, md5this);
free(md5this); /* free this again */
md5_to_ascii(md5buf, request_digest);
/* for test case 64 (snooped from a Mozilla 1.3a request)
Authorization: Digest username="testuser", realm="testrealm", \
nonce="1053604145", uri="/64", response="c55f7f30d83d774a3d2dcacf725abaca"
*/
if(d->qop) {
*allocuserpwd =
aprintf( "%sAuthorization: Digest "
"username=\"%s\", "
"realm=\"%s\", "
"nonce=\"%s\", "
"uri=\"%s\", "
"cnonce=\"%s\", "
"nc=%08x, "
"qop=%s, "
"response=\"%s\"",
proxy?"Proxy-":"",
userp,
d->realm,
d->nonce,
uripath, /* this is the PATH part of the URL */
d->cnonce,
d->nc,
d->qop,
request_digest);
if(Curl_raw_equal(d->qop, "auth"))
d->nc++; /* The nc (from RFC) has to be a 8 hex digit number 0 padded
which tells to the server how many times you are using the
same nonce in the qop=auth mode. */
}
else {
*allocuserpwd =
aprintf( "%sAuthorization: Digest "
"username=\"%s\", "
"realm=\"%s\", "
"nonce=\"%s\", "
"uri=\"%s\", "
"response=\"%s\"",
proxy?"Proxy-":"",
userp,
d->realm,
d->nonce,
uripath, /* this is the PATH part of the URL */
request_digest);
}
if(!*allocuserpwd)
return CURLE_OUT_OF_MEMORY;
/* Add optional fields */
if(d->opaque) {
/* append opaque */
tmp = aprintf("%s, opaque=\"%s\"", *allocuserpwd, d->opaque);
if(!tmp)
return CURLE_OUT_OF_MEMORY;
free(*allocuserpwd);
*allocuserpwd = tmp;
}
if(d->algorithm) {
/* append algorithm */
tmp = aprintf("%s, algorithm=\"%s\"", *allocuserpwd, d->algorithm);
if(!tmp)
return CURLE_OUT_OF_MEMORY;
free(*allocuserpwd);
*allocuserpwd = tmp;
}
/* append CRLF + zero (3 bytes) to the userpwd header */
userlen = strlen(*allocuserpwd);
tmp = realloc(*allocuserpwd, userlen + 3);
if(!tmp)
return CURLE_OUT_OF_MEMORY;
strcpy(&tmp[userlen], "\r\n"); /* append the data */
*allocuserpwd = tmp;
return CURLE_OK;
}
static void digest_cleanup_one(struct digestdata *d)
{
if(d->nonce)
free(d->nonce);
d->nonce = NULL;
if(d->cnonce)
free(d->cnonce);
d->cnonce = NULL;
if(d->realm)
free(d->realm);
d->realm = NULL;
if(d->opaque)
free(d->opaque);
d->opaque = NULL;
if(d->qop)
free(d->qop);
d->qop = NULL;
if(d->algorithm)
free(d->algorithm);
d->algorithm = NULL;
d->nc = 0;
d->algo = CURLDIGESTALGO_MD5; /* default algorithm */
d->stale = FALSE; /* default means normal, not stale */
}
void Curl_digest_cleanup(struct SessionHandle *data)
{
digest_cleanup_one(&data->state.digest);
digest_cleanup_one(&data->state.proxydigest);
}
#endif
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