From 6f8d8131b1a430002bb1ca214d0e66e3475a195e Mon Sep 17 00:00:00 2001 From: Steve Holme Date: Wed, 5 Nov 2014 15:01:51 +0000 Subject: http_digest: Moved response generation into SASL module --- lib/curl_sasl.c | 283 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 283 insertions(+) (limited to 'lib/curl_sasl.c') diff --git a/lib/curl_sasl.c b/lib/curl_sasl.c index 3169730b5..fd2585e3d 100644 --- a/lib/curl_sasl.c +++ b/lib/curl_sasl.c @@ -43,6 +43,7 @@ #include "curl_memory.h" #include "strtok.h" #include "rawstr.h" +#include "non-ascii.h" /* included for Curl_convert_... prototypes */ #ifdef USE_NSS #include "vtls/nssg.h" /* for Curl_nss_force_init() */ @@ -73,6 +74,17 @@ extern void Curl_sasl_gssapi_cleanup(struct kerberos5data *krb5); #define DIGEST_MAX_VALUE_LENGTH 256 #define DIGEST_MAX_CONTENT_LENGTH 1024 +/* 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) \ + result = Curl_convert_to_network(a, (char *)b, strlen((const char*)b)); \ + if(result) { \ + free(b); \ + return result; \ + } + /* * Return 0 on success and then the buffers are filled in fine. * @@ -141,6 +153,47 @@ static int sasl_digest_get_pair(const char *str, char *value, char *content, return 0; /* all is fine! */ } +/* Convert md5 chunk to RFC2617 (section 3.1.3) -suitable ascii string*/ +static void sasl_digest_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]); +} + +/* Perform quoted-string escaping as described in RFC2616 and its errata */ +static char *sasl_digest_string_quoted(const char *source) +{ + char *dest, *d; + const char *s = source; + size_t n = 1; /* null terminator */ + + /* Calculate size needed */ + while(*s) { + ++n; + if(*s == '"' || *s == '\\') { + ++n; + } + ++s; + } + + dest = malloc(n); + if(dest) { + s = source; + d = dest; + while(*s) { + if(*s == '"' || *s == '\\') { + *d++ = '\\'; + } + *d++ = *s++; + } + *d = 0; + } + + return dest; +} + #if !defined(USE_WINDOWS_SSPI) /* Retrieves the value for a corresponding key from the challenge string * returns TRUE if the key could be found, FALSE if it does not exists @@ -790,6 +843,236 @@ CURLcode Curl_sasl_decode_digest_http_message(const char *chlg, return CURLE_OK; } +/* + * Curl_sasl_create_digest_http_message() + * + * This is used to generate a HTTP DIGEST response message ready for sending + * to the recipient. + * + * Parameters: + * + * data [in] - The session handle. + * userp [in] - The user name. + * passdwp [in] - The user's password. + * request [in] - The HTTP request. + * uripath [in] - The path of the HTTP uri. + * digest [in/out] - The digest data struct being used and modified. + * outptr [in/out] - The address where a pointer to newly allocated memory + * holding the result will be stored upon completion. + * outlen [out] - The length of the output message. + * + * Returns CURLE_OK on success. + */ +CURLcode Curl_sasl_create_digest_http_message(struct SessionHandle *data, + const char *userp, + const char *passwdp, + const unsigned char *request, + const unsigned char *uripath, + struct digestdata *digest, + char **outptr, size_t *outlen) +{ + CURLcode result; + unsigned char md5buf[16]; /* 16 bytes/128 bits */ + unsigned char request_digest[33]; + unsigned char *md5this; + unsigned char ha1[33];/* 32 digits and 1 zero byte */ + unsigned char ha2[33];/* 32 digits and 1 zero byte */ + char cnoncebuf[33]; + char *cnonce = NULL; + size_t cnonce_sz = 0; + char *userp_quoted; + char *response = NULL; + char *tmp = NULL; + + if(!digest->nc) + digest->nc = 1; + + if(!digest->cnonce) { + snprintf(cnoncebuf, sizeof(cnoncebuf), "%08x%08x%08x%08x", + Curl_rand(data), Curl_rand(data), + Curl_rand(data), Curl_rand(data)); + + result = Curl_base64_encode(data, cnoncebuf, strlen(cnoncebuf), + &cnonce, &cnonce_sz); + if(result) + return result; + + digest->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, digest->realm, passwdp); + if(!md5this) + return CURLE_OUT_OF_MEMORY; + + CURL_OUTPUT_DIGEST_CONV(data, md5this); /* convert on non-ASCII machines */ + Curl_md5it(md5buf, md5this); + Curl_safefree(md5this); + sasl_digest_md5_to_ascii(md5buf, ha1); + + if(digest->algo == CURLDIGESTALGO_MD5SESS) { + /* nonce and cnonce are OUTSIDE the hash */ + tmp = aprintf("%s:%s:%s", ha1, digest->nonce, digest->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); + Curl_safefree(tmp); + sasl_digest_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) + */ + + md5this = (unsigned char *)aprintf("%s:%s", request, uripath); + + if(digest->qop && Curl_raw_equal(digest->qop, "auth-int")) { + /* We don't support auth-int for PUT or POST at the moment. + TODO: replace md5 of empty string with entity-body for PUT/POST */ + unsigned char *md5this2 = (unsigned char *) + aprintf("%s:%s", md5this, "d41d8cd98f00b204e9800998ecf8427e"); + Curl_safefree(md5this); + md5this = md5this2; + } + + if(!md5this) + return CURLE_OUT_OF_MEMORY; + + CURL_OUTPUT_DIGEST_CONV(data, md5this); /* convert on non-ASCII machines */ + Curl_md5it(md5buf, md5this); + Curl_safefree(md5this); + sasl_digest_md5_to_ascii(md5buf, ha2); + + if(digest->qop) { + md5this = (unsigned char *)aprintf("%s:%s:%08x:%s:%s:%s", + ha1, + digest->nonce, + digest->nc, + digest->cnonce, + digest->qop, + ha2); + } + else { + md5this = (unsigned char *)aprintf("%s:%s:%s", + ha1, + digest->nonce, + ha2); + } + + if(!md5this) + return CURLE_OUT_OF_MEMORY; + + CURL_OUTPUT_DIGEST_CONV(data, md5this); /* convert on non-ASCII machines */ + Curl_md5it(md5buf, md5this); + Curl_safefree(md5this); + sasl_digest_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" + + Digest parameters are all quoted strings. Username which is provided by + the user will need double quotes and backslashes within it escaped. For + the other fields, this shouldn't be an issue. realm, nonce, and opaque + are copied as is from the server, escapes and all. cnonce is generated + with web-safe characters. uri is already percent encoded. nc is 8 hex + characters. algorithm and qop with standard values only contain web-safe + chracters. + */ + userp_quoted = sasl_digest_string_quoted(userp); + if(!userp_quoted) + return CURLE_OUT_OF_MEMORY; + + if(digest->qop) { + response = aprintf("username=\"%s\", " + "realm=\"%s\", " + "nonce=\"%s\", " + "uri=\"%s\", " + "cnonce=\"%s\", " + "nc=%08x, " + "qop=%s, " + "response=\"%s\"", + userp_quoted, + digest->realm, + digest->nonce, + uripath, + digest->cnonce, + digest->nc, + digest->qop, + request_digest); + + if(Curl_raw_equal(digest->qop, "auth")) + digest->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 { + response = aprintf("username=\"%s\", " + "realm=\"%s\", " + "nonce=\"%s\", " + "uri=\"%s\", " + "response=\"%s\"", + userp_quoted, + digest->realm, + digest->nonce, + uripath, + request_digest); + } + Curl_safefree(userp_quoted); + if(!response) + return CURLE_OUT_OF_MEMORY; + + /* Add the optional fields */ + if(digest->opaque) { + /* Append the opaque */ + tmp = aprintf("%s, opaque=\"%s\"", response, digest->opaque); + if(!tmp) + return CURLE_OUT_OF_MEMORY; + + free(response); + response = tmp; + } + + if(digest->algorithm) { + /* Append the algorithm */ + tmp = aprintf("%s, algorithm=\"%s\"", response, digest->algorithm); + if(!tmp) + return CURLE_OUT_OF_MEMORY; + + free(response); + response = tmp; + } + + /* Return the output */ + *outptr = response; + *outlen = strlen(response); + + return CURLE_OK; +} + /* * Curl_sasl_digest_cleanup() * -- cgit v1.2.3