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Verify Content-Type from smart HTTP servers

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Before parsing a suspected smart-HTTP response verify the returned
Content-Type matches the standard. This protects a client from
attempting to process a payload that smells like a smart-HTTP
server response.

JGit has been doing this check on all responses since the dawn of
time. I mistakenly failed to include it in git-core when smart HTTP
was introduced. At the time I didn't know how to get the Content-Type
from libcurl. I punted, meant to circle back and fix this, and just
plain forgot about it.

Signed-off-by: Shawn Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Shawn Pearce 2013-01-31 13:02:07 -08:00 committed by Junio C Hamano
parent e1b6ff44d6
commit 4656bf47fc
8 changed files with 59 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
http-push.c
View File

@ -1560,7 +1560,7 @@ static int remote_exists(const char *path)
sprintf(url, "%s%s", repo->url, path);
switch (http_get_strbuf(url, NULL, 0)) {
switch (http_get_strbuf(url, NULL, NULL, 0)) {
case HTTP_OK:
ret = 1;
break;
@ -1584,7 +1584,7 @@ static void fetch_symref(const char *path, char **symref, unsigned char *sha1)
url = xmalloc(strlen(repo->url) + strlen(path) + 1);
sprintf(url, "%s%s", repo->url, path);
if (http_get_strbuf(url, &buffer, 0) != HTTP_OK)
if (http_get_strbuf(url, NULL, &buffer, 0) != HTTP_OK)
die("Couldn't get %s for remote symref\n%s", url,
curl_errorstr);
free(url);

31
http.c
View File

@ -788,7 +788,8 @@ int handle_curl_result(struct slot_results *results)
#define HTTP_REQUEST_STRBUF 0
#define HTTP_REQUEST_FILE 1
static int http_request(const char *url, void *result, int target, int options)
static int http_request(const char *url, struct strbuf *type,
void *result, int target, int options)
{
struct active_request_slot *slot;
struct slot_results results;
@ -838,24 +839,36 @@ static int http_request(const char *url, void *result, int target, int options)
ret = HTTP_START_FAILED;
}
if (type) {
char *t;
curl_easy_getinfo(slot->curl, CURLINFO_CONTENT_TYPE, &t);
if (t)
strbuf_addstr(type, t);
}
curl_slist_free_all(headers);
strbuf_release(&buf);
return ret;
}
static int http_request_reauth(const char *url, void *result, int target,
static int http_request_reauth(const char *url,
struct strbuf *type,
void *result, int target,
int options)
{
int ret = http_request(url, result, target, options);
int ret = http_request(url, type, result, target, options);
if (ret != HTTP_REAUTH)
return ret;
return http_request(url, result, target, options);
return http_request(url, type, result, target, options);
}
int http_get_strbuf(const char *url, struct strbuf *result, int options)
int http_get_strbuf(const char *url,
struct strbuf *type,
struct strbuf *result, int options)
{
return http_request_reauth(url, result, HTTP_REQUEST_STRBUF, options);
return http_request_reauth(url, type, result,
HTTP_REQUEST_STRBUF, options);
}
/*
@ -878,7 +891,7 @@ static int http_get_file(const char *url, const char *filename, int options)
goto cleanup;
}
ret = http_request_reauth(url, result, HTTP_REQUEST_FILE, options);
ret = http_request_reauth(url, NULL, result, HTTP_REQUEST_FILE, options);
fclose(result);
if ((ret == HTTP_OK) && move_temp_to_file(tmpfile.buf, filename))
@ -904,7 +917,7 @@ int http_fetch_ref(const char *base, struct ref *ref)
int ret = -1;
url = quote_ref_url(base, ref->name);
if (http_get_strbuf(url, &buffer, HTTP_NO_CACHE) == HTTP_OK) {
if (http_get_strbuf(url, NULL, &buffer, HTTP_NO_CACHE) == HTTP_OK) {
strbuf_rtrim(&buffer);
if (buffer.len == 40)
ret = get_sha1_hex(buffer.buf, ref->old_sha1);
@ -997,7 +1010,7 @@ int http_get_info_packs(const char *base_url, struct packed_git **packs_head)
strbuf_addstr(&buf, "objects/info/packs");
url = strbuf_detach(&buf, NULL);
ret = http_get_strbuf(url, &buf, HTTP_NO_CACHE);
ret = http_get_strbuf(url, NULL, &buf, HTTP_NO_CACHE);
if (ret != HTTP_OK)
goto cleanup;

2
http.h
View File

@ -132,7 +132,7 @@ extern char *get_remote_object_url(const char *url, const char *hex,
*
* If the result pointer is NULL, a HTTP HEAD request is made instead of GET.
*/
int http_get_strbuf(const char *url, struct strbuf *result, int options);
int http_get_strbuf(const char *url, struct strbuf *content_type, struct strbuf *result, int options);
/*
* Prints an error message using error() containing url and curl_errorstr,

17
remote-curl.c
View File

@ -92,6 +92,8 @@ static void free_discovery(struct discovery *d)
static struct discovery* discover_refs(const char *service)
{
struct strbuf exp = STRBUF_INIT;
struct strbuf type = STRBUF_INIT;
struct strbuf buffer = STRBUF_INIT;
struct discovery *last = last_discovery;
char *refs_url;
@ -113,7 +115,7 @@ static struct discovery* discover_refs(const char *service)
}
refs_url = strbuf_detach(&buffer, NULL);
http_ret = http_get_strbuf(refs_url, &buffer, HTTP_NO_CACHE);
http_ret = http_get_strbuf(refs_url, &type, &buffer, HTTP_NO_CACHE);
switch (http_ret) {
case HTTP_OK:
break;
@ -132,17 +134,20 @@ static struct discovery* discover_refs(const char *service)
last->buf_alloc = strbuf_detach(&buffer, &last->len);
last->buf = last->buf_alloc;
if (maybe_smart && 5 <= last->len && last->buf[4] == '#') {
/* smart HTTP response; validate that the service
strbuf_addf(&exp, "application/x-%s-advertisement", service);
if (maybe_smart &&
(5 <= last->len && last->buf[4] == '#') &&
!strbuf_cmp(&exp, &type)) {
/*
* smart HTTP response; validate that the service
* pkt-line matches our request.
*/
struct strbuf exp = STRBUF_INIT;
if (packet_get_line(&buffer, &last->buf, &last->len) <= 0)
die("%s has invalid packet header", refs_url);
if (buffer.len && buffer.buf[buffer.len - 1] == '\n')
strbuf_setlen(&buffer, buffer.len - 1);
strbuf_reset(&exp);
strbuf_addf(&exp, "# service=%s", service);
if (strbuf_cmp(&exp, &buffer))
die("invalid server response; got '%s'", buffer.buf);
@ -160,6 +165,8 @@ static struct discovery* discover_refs(const char *service)
}
free(refs_url);
strbuf_release(&exp);
strbuf_release(&type);
strbuf_release(&buffer);
last_discovery = last;
return last;

1
t/lib-httpd.sh
View File

@ -80,6 +80,7 @@ fi
prepare_httpd() {
mkdir -p "$HTTPD_DOCUMENT_ROOT_PATH"
cp "$TEST_PATH"/passwd "$HTTPD_ROOT_PATH"
cp "$TEST_PATH"/broken-smart-http.sh "$HTTPD_ROOT_PATH"
ln -s "$LIB_HTTPD_MODULE_PATH" "$HTTPD_ROOT_PATH/modules"

4
t/lib-httpd/apache.conf
View File

@ -62,9 +62,13 @@ Alias /auth/dumb/ www/auth/dumb/
SetEnv GIT_COMMITTER_EMAIL custom@example.com
</LocationMatch>
ScriptAliasMatch /smart_*[^/]*/(.*) ${GIT_EXEC_PATH}/git-http-backend/$1
ScriptAlias /broken_smart/ broken-smart-http.sh/
<Directory ${GIT_EXEC_PATH}>
Options FollowSymlinks
</Directory>
<Files broken-smart-http.sh>
Options ExecCGI
</Files>
<Files ${GIT_EXEC_PATH}/git-http-backend>
Options ExecCGI
</Files>

11
t/lib-httpd/broken-smart-http.sh Executable file
View File

@ -0,0 +1,11 @@
#!/bin/sh
printf "Content-Type: text/%s\n" "html"
echo
printf "%s\n" "001e# service=git-upload-pack"
printf "%s" "0000"
printf "%s%c%s%s\n" \
"00a58681d9f286a48b08f37b3a095330da16689e3693 HEAD" \
0 \
" include-tag multi_ack_detailed multi_ack ofs-delta" \
" side-band side-band-64k thin-pack no-progress shallow no-done "
printf "%s" "0000"

6
t/t5551-http-fetch.sh
View File

@ -157,6 +157,12 @@ test_expect_success 'GIT_SMART_HTTP can disable smart http' '
test_must_fail git fetch)
'
test_expect_success 'invalid Content-Type rejected' '
echo "fatal: invalid content-type text/html" >expect
test_must_fail git clone $HTTPD_URL/broken_smart/repo.git 2>actual
test_cmp expect actual
'
test -n "$GIT_TEST_LONG" && test_set_prereq EXPENSIVE
test_expect_success EXPENSIVE 'create 50,000 tags in the repo' '