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e92edfbef6
curl/lib/http_aws_sigv4.c
Wyatt O'Day e92edfbef6
lib: add ability to disable auths individually 
Both with configure and cmake

Closes #11490
2023-09-07 17:45:06 +02:00

650 lines
19 KiB
C
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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 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 https://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.
*
* SPDX-License-Identifier: curl
*
***************************************************************************/
#include "curl_setup.h"
#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_AWS)
#include "urldata.h"
#include "strcase.h"
#include "strdup.h"
#include "http_aws_sigv4.h"
#include "curl_sha256.h"
#include "transfer.h"
#include "parsedate.h"
#include "sendf.h"
#include <time.h>
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
#include "slist.h"
#define HMAC_SHA256(k, kl, d, dl, o) \
do { \
ret = Curl_hmacit(Curl_HMAC_SHA256, \
(unsigned char *)k, \
kl, \
(unsigned char *)d, \
dl, o); \
if(ret) { \
goto fail; \
} \
} while(0)
#define TIMESTAMP_SIZE 17
/* hex-encoded with trailing null */
#define SHA256_HEX_LENGTH (2 * SHA256_DIGEST_LENGTH + 1)
static void sha256_to_hex(char *dst, unsigned char *sha)
{
int i;
for(i = 0; i < SHA256_DIGEST_LENGTH; ++i) {
msnprintf(dst + (i * 2), SHA256_HEX_LENGTH - (i * 2), "%02x", sha[i]);
}
}
static char *find_date_hdr(struct Curl_easy *data, const char *sig_hdr)
{
char *tmp = Curl_checkheaders(data, sig_hdr, strlen(sig_hdr));
if(tmp)
return tmp;
return Curl_checkheaders(data, STRCONST("Date"));
}
/* remove whitespace, and lowercase all headers */
static void trim_headers(struct curl_slist *head)
{
struct curl_slist *l;
for(l = head; l; l = l->next) {
char *value; /* to read from */
char *store;
size_t colon = strcspn(l->data, ":");
Curl_strntolower(l->data, l->data, colon);
value = &l->data[colon];
if(!*value)
continue;
++value;
store = value;
/* skip leading whitespace */
while(*value && ISBLANK(*value))
value++;
while(*value) {
int space = 0;
while(*value && ISBLANK(*value)) {
value++;
space++;
}
if(space) {
/* replace any number of consecutive whitespace with a single space,
unless at the end of the string, then nothing */
if(*value)
*store++ = ' ';
}
else
*store++ = *value++;
}
*store = 0; /* null terminate */
}
}
/* maximum length for the aws sivg4 parts */
#define MAX_SIGV4_LEN 64
#define MAX_SIGV4_LEN_TXT "64"
#define DATE_HDR_KEY_LEN (MAX_SIGV4_LEN + sizeof("X--Date"))
#define MAX_HOST_LEN 255
/* FQDN + host: */
#define FULL_HOST_LEN (MAX_HOST_LEN + sizeof("host:"))
/* string been x-PROVIDER-date:TIMESTAMP, I need +1 for ':' */
#define DATE_FULL_HDR_LEN (DATE_HDR_KEY_LEN + TIMESTAMP_SIZE + 1)
/* timestamp should point to a buffer of at last TIMESTAMP_SIZE bytes */
static CURLcode make_headers(struct Curl_easy *data,
const char *hostname,
char *timestamp,
char *provider1,
char **date_header,
char *content_sha256_header,
struct dynbuf *canonical_headers,
struct dynbuf *signed_headers)
{
char date_hdr_key[DATE_HDR_KEY_LEN];
char date_full_hdr[DATE_FULL_HDR_LEN];
struct curl_slist *head = NULL;
struct curl_slist *tmp_head = NULL;
CURLcode ret = CURLE_OUT_OF_MEMORY;
struct curl_slist *l;
int again = 1;
/* provider1 mid */
Curl_strntolower(provider1, provider1, strlen(provider1));
provider1[0] = Curl_raw_toupper(provider1[0]);
msnprintf(date_hdr_key, DATE_HDR_KEY_LEN, "X-%s-Date", provider1);
/* provider1 lowercase */
Curl_strntolower(provider1, provider1, 1); /* first byte only */
msnprintf(date_full_hdr, DATE_FULL_HDR_LEN,
"x-%s-date:%s", provider1, timestamp);
if(Curl_checkheaders(data, STRCONST("Host"))) {
head = NULL;
}
else {
char full_host[FULL_HOST_LEN + 1];
if(data->state.aptr.host) {
size_t pos;
if(strlen(data->state.aptr.host) > FULL_HOST_LEN) {
ret = CURLE_URL_MALFORMAT;
goto fail;
}
strcpy(full_host, data->state.aptr.host);
/* remove /r/n as the separator for canonical request must be '\n' */
pos = strcspn(full_host, "\n\r");
full_host[pos] = 0;
}
else {
if(strlen(hostname) > MAX_HOST_LEN) {
ret = CURLE_URL_MALFORMAT;
goto fail;
}
msnprintf(full_host, FULL_HOST_LEN, "host:%s", hostname);
}
head = curl_slist_append(NULL, full_host);
if(!head)
goto fail;
}
if(*content_sha256_header) {
tmp_head = curl_slist_append(head, content_sha256_header);
if(!tmp_head)
goto fail;
head = tmp_head;
}
for(l = data->set.headers; l; l = l->next) {
tmp_head = curl_slist_append(head, l->data);
if(!tmp_head)
goto fail;
head = tmp_head;
}
trim_headers(head);
*date_header = find_date_hdr(data, date_hdr_key);
if(!*date_header) {
tmp_head = curl_slist_append(head, date_full_hdr);
if(!tmp_head)
goto fail;
head = tmp_head;
*date_header = curl_maprintf("%s: %s\r\n", date_hdr_key, timestamp);
}
else {
char *value;
value = strchr(*date_header, ':');
if(!value) {
*date_header = NULL;
goto fail;
}
++value;
while(ISBLANK(*value))
++value;
strncpy(timestamp, value, TIMESTAMP_SIZE - 1);
timestamp[TIMESTAMP_SIZE - 1] = 0;
*date_header = NULL;
}
/* alpha-sort in a case sensitive manner */
do {
again = 0;
for(l = head; l; l = l->next) {
struct curl_slist *next = l->next;
if(next && strcmp(l->data, next->data) > 0) {
char *tmp = l->data;
l->data = next->data;
next->data = tmp;
again = 1;
}
}
} while(again);
for(l = head; l; l = l->next) {
char *tmp;
if(Curl_dyn_add(canonical_headers, l->data))
goto fail;
if(Curl_dyn_add(canonical_headers, "\n"))
goto fail;
tmp = strchr(l->data, ':');
if(tmp)
*tmp = 0;
if(l != head) {
if(Curl_dyn_add(signed_headers, ";"))
goto fail;
}
if(Curl_dyn_add(signed_headers, l->data))
goto fail;
}
ret = CURLE_OK;
fail:
curl_slist_free_all(head);
return ret;
}
#define CONTENT_SHA256_KEY_LEN (MAX_SIGV4_LEN + sizeof("X--Content-Sha256"))
/* add 2 for ": " between header name and value */
#define CONTENT_SHA256_HDR_LEN (CONTENT_SHA256_KEY_LEN + 2 + \
SHA256_HEX_LENGTH)
/* try to parse a payload hash from the content-sha256 header */
static char *parse_content_sha_hdr(struct Curl_easy *data,
const char *provider1,
size_t *value_len)
{
char key[CONTENT_SHA256_KEY_LEN];
size_t key_len;
char *value;
size_t len;
key_len = msnprintf(key, sizeof(key), "x-%s-content-sha256", provider1);
value = Curl_checkheaders(data, key, key_len);
if(!value)
return NULL;
value = strchr(value, ':');
if(!value)
return NULL;
++value;
while(*value && ISBLANK(*value))
++value;
len = strlen(value);
while(len > 0 && ISBLANK(value[len-1]))
--len;
*value_len = len;
return value;
}
static CURLcode calc_payload_hash(struct Curl_easy *data,
unsigned char *sha_hash, char *sha_hex)
{
const char *post_data = data->set.postfields;
size_t post_data_len = 0;
CURLcode result;
if(post_data) {
if(data->set.postfieldsize < 0)
post_data_len = strlen(post_data);
else
post_data_len = (size_t)data->set.postfieldsize;
}
result = Curl_sha256it(sha_hash, (const unsigned char *) post_data,
post_data_len);
if(!result)
sha256_to_hex(sha_hex, sha_hash);
return result;
}
#define S3_UNSIGNED_PAYLOAD "UNSIGNED-PAYLOAD"
static CURLcode calc_s3_payload_hash(struct Curl_easy *data,
Curl_HttpReq httpreq, char *provider1,
unsigned char *sha_hash,
char *sha_hex, char *header)
{
bool empty_method = (httpreq == HTTPREQ_GET || httpreq == HTTPREQ_HEAD);
/* The request method or filesize indicate no request payload */
bool empty_payload = (empty_method || data->set.filesize == 0);
/* The POST payload is in memory */
bool post_payload = (httpreq == HTTPREQ_POST && data->set.postfields);
CURLcode ret = CURLE_OUT_OF_MEMORY;
if(empty_payload || post_payload) {
/* Calculate a real hash when we know the request payload */
ret = calc_payload_hash(data, sha_hash, sha_hex);
if(ret)
goto fail;
}
else {
/* Fall back to s3's UNSIGNED-PAYLOAD */
size_t len = sizeof(S3_UNSIGNED_PAYLOAD) - 1;
DEBUGASSERT(len < SHA256_HEX_LENGTH); /* 16 < 65 */
memcpy(sha_hex, S3_UNSIGNED_PAYLOAD, len);
sha_hex[len] = 0;
}
/* format the required content-sha256 header */
msnprintf(header, CONTENT_SHA256_HDR_LEN,
"x-%s-content-sha256: %s", provider1, sha_hex);
ret = CURLE_OK;
fail:
return ret;
}
CURLcode Curl_output_aws_sigv4(struct Curl_easy *data, bool proxy)
{
CURLcode ret = CURLE_OUT_OF_MEMORY;
struct connectdata *conn = data->conn;
size_t len;
const char *arg;
char provider0[MAX_SIGV4_LEN + 1]="";
char provider1[MAX_SIGV4_LEN + 1]="";
char region[MAX_SIGV4_LEN + 1]="";
char service[MAX_SIGV4_LEN + 1]="";
bool sign_as_s3 = false;
const char *hostname = conn->host.name;
time_t clock;
struct tm tm;
char timestamp[TIMESTAMP_SIZE];
char date[9];
struct dynbuf canonical_headers;
struct dynbuf signed_headers;
char *date_header = NULL;
Curl_HttpReq httpreq;
const char *method = NULL;
char *payload_hash = NULL;
size_t payload_hash_len = 0;
unsigned char sha_hash[SHA256_DIGEST_LENGTH];
char sha_hex[SHA256_HEX_LENGTH];
char content_sha256_hdr[CONTENT_SHA256_HDR_LEN + 2] = ""; /* add \r\n */
char *canonical_request = NULL;
char *request_type = NULL;
char *credential_scope = NULL;
char *str_to_sign = NULL;
const char *user = data->state.aptr.user ? data->state.aptr.user : "";
char *secret = NULL;
unsigned char sign0[SHA256_DIGEST_LENGTH] = {0};
unsigned char sign1[SHA256_DIGEST_LENGTH] = {0};
char *auth_headers = NULL;
DEBUGASSERT(!proxy);
(void)proxy;
if(Curl_checkheaders(data, STRCONST("Authorization"))) {
/* Authorization already present, Bailing out */
return CURLE_OK;
}
/* we init those buffers here, so goto fail will free initialized dynbuf */
Curl_dyn_init(&canonical_headers, CURL_MAX_HTTP_HEADER);
Curl_dyn_init(&signed_headers, CURL_MAX_HTTP_HEADER);
/*
* Parameters parsing
* Google and Outscale use the same OSC or GOOG,
* but Amazon uses AWS and AMZ for header arguments.
* AWS is the default because most of non-amazon providers
* are still using aws:amz as a prefix.
*/
arg = data->set.str[STRING_AWS_SIGV4] ?
data->set.str[STRING_AWS_SIGV4] : "aws:amz";
/* provider1[:provider2[:region[:service]]]
No string can be longer than N bytes of non-whitespace
*/
(void)sscanf(arg, "%" MAX_SIGV4_LEN_TXT "[^:]"
":%" MAX_SIGV4_LEN_TXT "[^:]"
":%" MAX_SIGV4_LEN_TXT "[^:]"
":%" MAX_SIGV4_LEN_TXT "s",
provider0, provider1, region, service);
if(!provider0[0]) {
failf(data, "first provider can't be empty");
ret = CURLE_BAD_FUNCTION_ARGUMENT;
goto fail;
}
else if(!provider1[0])
strcpy(provider1, provider0);
if(!service[0]) {
char *hostdot = strchr(hostname, '.');
if(!hostdot) {
failf(data, "service missing in parameters and hostname");
ret = CURLE_URL_MALFORMAT;
goto fail;
}
len = hostdot - hostname;
if(len > MAX_SIGV4_LEN) {
failf(data, "service too long in hostname");
ret = CURLE_URL_MALFORMAT;
goto fail;
}
strncpy(service, hostname, len);
service[len] = '\0';
if(!region[0]) {
const char *reg = hostdot + 1;
const char *hostreg = strchr(reg, '.');
if(!hostreg) {
failf(data, "region missing in parameters and hostname");
ret = CURLE_URL_MALFORMAT;
goto fail;
}
len = hostreg - reg;
if(len > MAX_SIGV4_LEN) {
failf(data, "region too long in hostname");
ret = CURLE_URL_MALFORMAT;
goto fail;
}
strncpy(region, reg, len);
region[len] = '\0';
}
}
Curl_http_method(data, conn, &method, &httpreq);
/* AWS S3 requires a x-amz-content-sha256 header, and supports special
* values like UNSIGNED-PAYLOAD */
sign_as_s3 = (strcasecompare(provider0, "aws") &&
strcasecompare(service, "s3"));
payload_hash = parse_content_sha_hdr(data, provider1, &payload_hash_len);
if(!payload_hash) {
if(sign_as_s3)
ret = calc_s3_payload_hash(data, httpreq, provider1, sha_hash,
sha_hex, content_sha256_hdr);
else
ret = calc_payload_hash(data, sha_hash, sha_hex);
if(ret)
goto fail;
payload_hash = sha_hex;
/* may be shorter than SHA256_HEX_LENGTH, like S3_UNSIGNED_PAYLOAD */
payload_hash_len = strlen(sha_hex);
}
#ifdef DEBUGBUILD
{
char *force_timestamp = getenv("CURL_FORCETIME");
if(force_timestamp)
clock = 0;
else
time(&clock);
}
#else
time(&clock);
#endif
ret = Curl_gmtime(clock, &tm);
if(ret) {
goto fail;
}
if(!strftime(timestamp, sizeof(timestamp), "%Y%m%dT%H%M%SZ", &tm)) {
ret = CURLE_OUT_OF_MEMORY;
goto fail;
}
ret = make_headers(data, hostname, timestamp, provider1,
&date_header, content_sha256_hdr,
&canonical_headers, &signed_headers);
if(ret)
goto fail;
ret = CURLE_OUT_OF_MEMORY;
if(*content_sha256_hdr) {
/* make_headers() needed this without the \r\n for canonicalization */
size_t hdrlen = strlen(content_sha256_hdr);
DEBUGASSERT(hdrlen + 3 < sizeof(content_sha256_hdr));
memcpy(content_sha256_hdr + hdrlen, "\r\n", 3);
}
memcpy(date, timestamp, sizeof(date));
date[sizeof(date) - 1] = 0;
canonical_request =
curl_maprintf("%s\n" /* HTTPRequestMethod */
"%s\n" /* CanonicalURI */
"%s\n" /* CanonicalQueryString */
"%s\n" /* CanonicalHeaders */
"%s\n" /* SignedHeaders */
"%.*s", /* HashedRequestPayload in hex */
method,
data->state.up.path,
data->state.up.query ? data->state.up.query : "",
Curl_dyn_ptr(&canonical_headers),
Curl_dyn_ptr(&signed_headers),
(int)payload_hash_len, payload_hash);
if(!canonical_request)
goto fail;
/* provider 0 lowercase */
Curl_strntolower(provider0, provider0, strlen(provider0));
request_type = curl_maprintf("%s4_request", provider0);
if(!request_type)
goto fail;
credential_scope = curl_maprintf("%s/%s/%s/%s",
date, region, service, request_type);
if(!credential_scope)
goto fail;
if(Curl_sha256it(sha_hash, (unsigned char *) canonical_request,
strlen(canonical_request)))
goto fail;
sha256_to_hex(sha_hex, sha_hash);
/* provider 0 uppercase */
Curl_strntoupper(provider0, provider0, strlen(provider0));
/*
* Google allows using RSA key instead of HMAC, so this code might change
* in the future. For now we only support HMAC.
*/
str_to_sign = curl_maprintf("%s4-HMAC-SHA256\n" /* Algorithm */
"%s\n" /* RequestDateTime */
"%s\n" /* CredentialScope */
"%s", /* HashedCanonicalRequest in hex */
provider0,
timestamp,
credential_scope,
sha_hex);
if(!str_to_sign) {
goto fail;
}
/* provider 0 uppercase */
secret = curl_maprintf("%s4%s", provider0,
data->state.aptr.passwd ?
data->state.aptr.passwd : "");
if(!secret)
goto fail;
HMAC_SHA256(secret, strlen(secret), date, strlen(date), sign0);
HMAC_SHA256(sign0, sizeof(sign0), region, strlen(region), sign1);
HMAC_SHA256(sign1, sizeof(sign1), service, strlen(service), sign0);
HMAC_SHA256(sign0, sizeof(sign0), request_type, strlen(request_type), sign1);
HMAC_SHA256(sign1, sizeof(sign1), str_to_sign, strlen(str_to_sign), sign0);
sha256_to_hex(sha_hex, sign0);
/* provider 0 uppercase */
auth_headers = curl_maprintf("Authorization: %s4-HMAC-SHA256 "
"Credential=%s/%s, "
"SignedHeaders=%s, "
"Signature=%s\r\n"
/*
* date_header is added here, only if it wasn't
* user-specified (using CURLOPT_HTTPHEADER).
* date_header includes \r\n
*/
"%s"
"%s", /* optional sha256 header includes \r\n */
provider0,
user,
credential_scope,
Curl_dyn_ptr(&signed_headers),
sha_hex,
date_header ? date_header : "",
content_sha256_hdr);
if(!auth_headers) {
goto fail;
}
Curl_safefree(data->state.aptr.userpwd);
data->state.aptr.userpwd = auth_headers;
data->state.authhost.done = TRUE;
ret = CURLE_OK;
fail:
Curl_dyn_free(&canonical_headers);
Curl_dyn_free(&signed_headers);
free(canonical_request);
free(request_type);
free(credential_scope);
free(str_to_sign);
free(secret);
free(date_header);
return ret;
}
#endif /* !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_AWS) */
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