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@xxxxxxxxxxx>
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
* The original was picked up by majordomo taboo rules; resending
after minor style fix.
Was there a report of an attempted attack by malicious server or
something that triggered this, or is this just a "common sense
thing to do" in general?
http-push.c | 4 ++--
http.c | 31 ++++++++++++++++++++++---------
http.h | 2 +-
remote-curl.c | 15 +++++++++++----
t/lib-httpd.sh | 1 +
t/lib-httpd/apache.conf | 4 ++++
t/lib-httpd/broken-smart-http.sh | 11 +++++++++++
t/t5551-http-fetch.sh | 6 ++++++
8 files changed, 58 insertions(+), 16 deletions(-)
create mode 100755 t/lib-httpd/broken-smart-http.sh
diff --git a/http-push.c b/http-push.c
index 8701c12..ba45b7b 100644
--- a/http-push.c
+++ b/http-push.c
@@ -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);
diff --git a/http.c b/http.c
index 44f3525..d868d8b 100644
--- a/http.c
+++ b/http.c
@@ -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;
diff --git a/http.h b/http.h
index 0a80d30..25d1931 100644
--- a/http.h
+++ b/http.h
@@ -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,
diff --git a/remote-curl.c b/remote-curl.c
index 9a8b123..e6f3b63 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -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;
@@ -133,16 +135,19 @@ static struct discovery* discover_refs(const char *service)
last->buf = last->buf_alloc;
if (maybe_smart && 5 <= last->len && last->buf[4] == '#') {
- /* smart HTTP response; validate that the service
+ /*
+ * smart HTTP response; validate that the service
* pkt-line matches our request.
*/
- struct strbuf exp = STRBUF_INIT;
-
+ strbuf_addf(&exp, "application/x-%s-advertisement", service);
+ if (strbuf_cmp(&exp, &type))
+ die("invalid content-type %s", type.buf);
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;
diff --git a/t/lib-httpd.sh b/t/lib-httpd.sh
index 02f442b..895b925 100644
--- a/t/lib-httpd.sh
+++ b/t/lib-httpd.sh
@@ -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"
diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
index fe76e84..938b4cf 100644
--- a/t/lib-httpd/apache.conf
+++ b/t/lib-httpd/apache.conf
@@ -62,9 +62,13 @@ Alias /auth/dumb/ www/auth/dumb/
SetEnv GIT_COMMITTER_EMAIL custom@xxxxxxxxxxx
</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>
diff --git a/t/lib-httpd/broken-smart-http.sh b/t/lib-httpd/broken-smart-http.sh
new file mode 100755
index 0000000..f7ebfff
--- /dev/null
+++ b/t/lib-httpd/broken-smart-http.sh
@@ -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"
diff --git a/t/t5551-http-fetch.sh b/t/t5551-http-fetch.sh
index c5cd2e3..cb95b95 100755
--- a/t/t5551-http-fetch.sh
+++ b/t/t5551-http-fetch.sh
@@ -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' '
--
1.8.1.2.605.gb99210a
--
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