--- Begin Message ---
|
Subject: |
[PATCH] gnu: transmission: Fix a DNS rebinding vulnerability that allows RCE. |
|
Date: |
Thu, 11 Jan 2018 15:20:48 -0800 |
As the patch commentary says, I adapted this patch to apply to the
latest Transmission release. However, there is a new test failure with
these changes, so I'm waiting for advice:
https://github.com/transmission/transmission/pull/468#issuecomment-357091126
* gnu/packages/patches/transmission-fix-dns-rebinding-vuln.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/bittorrent.scm (transmission)[source]: Use it.
---
gnu/local.mk | 1 +
gnu/packages/bittorrent.scm | 1 +
.../transmission-fix-dns-rebinding-vuln.patch | 302 +++++++++++++++++++++
3 files changed, 304 insertions(+)
create mode 100644
gnu/packages/patches/transmission-fix-dns-rebinding-vuln.patch
diff --git a/gnu/local.mk b/gnu/local.mk
index eec46af0d..c77c446ee 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1107,6 +1107,7 @@ dist_patch_DATA =
\
%D%/packages/patches/tipp10-fix-compiling.patch \
%D%/packages/patches/tipp10-remove-license-code.patch \
%D%/packages/patches/tk-find-library.patch \
+ %D%/packages/patches/transmission-fix-dns-rebinding-vuln.patch \
%D%/packages/patches/ttf2eot-cstddef.patch \
%D%/packages/patches/ttfautohint-source-date-epoch.patch \
%D%/packages/patches/tophat-build-with-later-seqan.patch \
diff --git a/gnu/packages/bittorrent.scm b/gnu/packages/bittorrent.scm
index eca064620..800a42eea 100644
--- a/gnu/packages/bittorrent.scm
+++ b/gnu/packages/bittorrent.scm
@@ -66,6 +66,7 @@
(uri (string-append
"https://transmission.cachefly.net/transmission-";
version ".tar.xz"))
+ (patches (search-patches
"transmission-fix-dns-rebinding-vuln.patch"))
(sha256
(base32
"0pykmhi7pdmzq47glbj8i2im6iarp4wnj4l1pyvsrnba61f0939s"))))
diff --git a/gnu/packages/patches/transmission-fix-dns-rebinding-vuln.patch
b/gnu/packages/patches/transmission-fix-dns-rebinding-vuln.patch
new file mode 100644
index 000000000..5c3b6d165
--- /dev/null
+++ b/gnu/packages/patches/transmission-fix-dns-rebinding-vuln.patch
@@ -0,0 +1,302 @@
+Fix a weakness that allows remote code execution via the Transmission
+RPC server using DNS rebinding:
+
+https://bugs.chromium.org/p/project-zero/issues/detail?id=1447
+
+Patch adapted from Tavis Ormandy's patch on the Transmission master
+branch to the Transmission 2.92 release by Leo Famulari
+<address@hidden>:
+
+https://github.com/transmission/transmission/pull/468/commits
+
+From fe2d3c6e75088f3d9b6040ce06da3d530358bc2f Mon Sep 17 00:00:00 2001
+From: Tavis Ormandy <address@hidden>
+Date: Thu, 11 Jan 2018 10:00:41 -0800
+Subject: [PATCH] mitigate dns rebinding attacks against daemon
+
+---
+ libtransmission/quark.c | 2 +
+ libtransmission/quark.h | 2 +
+ libtransmission/rpc-server.c | 116 +++++++++++++++++++++++++++++++++++++----
+ libtransmission/rpc-server.h | 4 ++
+ libtransmission/session.c | 2 +
+ libtransmission/transmission.h | 1 +
+ libtransmission/web.c | 3 ++
+ 7 files changed, 121 insertions(+), 9 deletions(-)
+
+diff --git a/libtransmission/quark.c b/libtransmission/quark.c
+index 30cc2bca4..6de4bc221 100644
+--- a/libtransmission/quark.c
++++ b/libtransmission/quark.c
+@@ -297,6 +297,8 @@ static const struct tr_key_struct my_static[] =
+ { "rpc-version-minimum", 19 },
+ { "rpc-whitelist", 13 },
+ { "rpc-whitelist-enabled", 21 },
++ { "rpc-host-whitelist", 18 },
++ { "rpc-host-whitelist-enabled", 26 },
+ { "scrape", 6 },
+ { "scrape-paused-torrents-enabled", 30 },
+ { "scrapeState", 11 },
+diff --git a/libtransmission/quark.h b/libtransmission/quark.h
+index 7f5212733..21723dea9 100644
+--- a/libtransmission/quark.h
++++ b/libtransmission/quark.h
+@@ -299,6 +299,8 @@ enum
+ TR_KEY_rpc_version_minimum,
+ TR_KEY_rpc_whitelist,
+ TR_KEY_rpc_whitelist_enabled,
++ TR_KEY_rpc_host_whitelist,
++ TR_KEY_rpc_host_whitelist_enabled,
+ TR_KEY_scrape,
+ TR_KEY_scrape_paused_torrents_enabled,
+ TR_KEY_scrapeState,
+diff --git a/libtransmission/rpc-server.c b/libtransmission/rpc-server.c
+index a3485f3fa..a048dc8aa 100644
+--- a/libtransmission/rpc-server.c
++++ b/libtransmission/rpc-server.c
+@@ -52,6 +52,7 @@ struct tr_rpc_server
+ bool isEnabled;
+ bool isPasswordEnabled;
+ bool isWhitelistEnabled;
++ bool isHostWhitelistEnabled;
+ tr_port port;
+ char * url;
+ struct in_addr bindAddress;
+@@ -63,6 +64,7 @@ struct tr_rpc_server
+ char * password;
+ char * whitelistStr;
+ tr_list * whitelist;
++ tr_list * hostWhitelist;
+
+ char * sessionId;
+ time_t sessionIdExpiresAt;
+@@ -588,6 +590,49 @@ isAddressAllowed (const tr_rpc_server * server, const
char * address)
+ return false;
+ }
+
++static bool isHostnameAllowed(tr_rpc_server const* server, struct
evhttp_request* req)
++{
++ /* If password auth is enabled, any hostname is permitted. */
++ if (server->isPasswordEnabled)
++ {
++ return true;
++ }
++
++ char const* const host = evhttp_find_header(req->input_headers, "Host");
++
++ /* No host header, invalid request. */
++ if (host == NULL)
++ {
++ return false;
++ }
++
++ /* Host header might include the port. */
++ char* const hostname = tr_strndup(host, strcspn(host, ":"));
++
++ /* localhost or ipaddress is always acceptable. */
++ if (strcmp(hostname, "localhost") == 0 || strcmp(hostname, "localhost.")
== 0 || tr_addressIsIP(hostname))
++ {
++ tr_free(hostname);
++ return true;
++ }
++
++ /* Otherwise, hostname must be whitelisted. */
++ if (server->isHostWhitelistEnabled)
++ {
++ for (tr_list* l = server->hostWhitelist; l != NULL; l = l->next)
++ {
++ if (tr_wildmat(hostname, l->data))
++ {
++ tr_free(hostname);
++ return true;
++ }
++ }
++ }
++
++ tr_free(hostname);
++ return false;
++}
++
+ static bool
+ test_session_id (struct tr_rpc_server * server, struct evhttp_request * req)
+ {
+@@ -663,6 +708,23 @@ handle_request (struct evhttp_request * req, void * arg)
+ handle_upload (req, server);
+ }
+ #ifdef REQUIRE_SESSION_ID
++ else if (!isHostnameAllowed(server, req))
++ {
++ char* tmp = tr_strdup_printf(
++ "<p>Transmission received your request, but the hostname was
unrecognized.</p>"
++ "<p>To fix this, choose one of the following options:"
++ "<ul>"
++ "<li>Enable password authentication, then any hostname is
allowed.</li>"
++ "<li>Add the hostname you want to use to the whitelist in
settings.</li>"
++ "</ul></p>"
++ "<p>If you're editing settings.json, see the
'rpc-host-whitelist' and 'rpc-host-whitelist-enabled' entries.</p>"
++ "<p>This requirement has been added to help prevent "
++ "<a href=\"https://en.wikipedia.org/wiki/DNS_rebinding\";>DNS
Rebinding</a> "
++ "attacks.</p>");
++ send_simple_response(req, 421, tmp);
++ tr_free(tmp);
++ }
++
+ else if (!test_session_id (server, req))
+ {
+ const char * sessionId = get_current_session_id (server);
+@@ -674,7 +736,7 @@ handle_request (struct evhttp_request * req, void * arg)
+ "<li> When you get this 409 error message, resend your request
with the updated header"
+ "</ol></p>"
+ "<p>This requirement has been added to help prevent "
+- "<a
href=\"http://en.wikipedia.org/wiki/Cross-site_request_forgery\";>CSRF</a> "
++ "<a
href=\"https://en.wikipedia.org/wiki/Cross-site_request_forgery\";>CSRF</a> "
+ "attacks.</p>"
+ "<p><code>%s: %s</code></p>",
+ TR_RPC_SESSION_ID_HEADER, sessionId);
+@@ -875,19 +937,14 @@ tr_rpcGetUrl (const tr_rpc_server * server)
+ return server->url ? server->url : "";
+ }
+
+-void
+-tr_rpcSetWhitelist (tr_rpc_server * server, const char * whitelistStr)
++static void
++tr_rpcSetList (char const* whitelistStr, tr_list** list)
+ {
+ void * tmp;
+ const char * walk;
+
+- /* keep the string */
+- tmp = server->whitelistStr;
+- server->whitelistStr = tr_strdup (whitelistStr);
+- tr_free (tmp);
+-
+ /* clear out the old whitelist entries */
+- while ((tmp = tr_list_pop_front (&server->whitelist)))
++ while ((tmp = tr_list_pop_front (list)) != NULL)
+ tr_free (tmp);
+
+ /* build the new whitelist entries */
+@@ -896,7 +953,7 @@ tr_rpcSetWhitelist (tr_rpc_server * server, const char *
whitelistStr)
+ const char * delimiters = " ,;";
+ const size_t len = strcspn (walk, delimiters);
+ char * token = tr_strndup (walk, len);
+- tr_list_append (&server->whitelist, token);
++ tr_list_append (list, token);
+ if (strcspn (token, "+-") < len)
+ tr_logAddNamedInfo (MY_NAME, "Adding address to whitelist: %s (And it
has a '+' or '-'! Are you using an old ACL by mistake?)", token);
+ else
+@@ -909,6 +966,21 @@ tr_rpcSetWhitelist (tr_rpc_server * server, const char *
whitelistStr)
+ }
+ }
+
++void tr_rpcSetHostWhitelist(tr_rpc_server* server, char const* whitelistStr)
++{
++ tr_rpcSetList(whitelistStr, &server->hostWhitelist);
++}
++
++void tr_rpcSetWhitelist(tr_rpc_server* server, char const* whitelistStr)
++{
++ /* keep the string */
++ char* const tmp = server->whitelistStr;
++ server->whitelistStr = tr_strdup(whitelistStr);
++ tr_free(tmp);
++
++ tr_rpcSetList(whitelistStr, &server->whitelist);
++}
++
+ const char*
+ tr_rpcGetWhitelist (const tr_rpc_server * server)
+ {
+@@ -930,6 +1002,11 @@ tr_rpcGetWhitelistEnabled (const tr_rpc_server * server)
+ return server->isWhitelistEnabled;
+ }
+
++void tr_rpcSetHostWhitelistEnabled(tr_rpc_server* server, bool isEnabled)
++{
++ server->isHostWhitelistEnabled = isEnabled;
++}
++
+ /****
+ ***** PASSWORD
+ ****/
+@@ -1063,6 +1140,28 @@ tr_rpcInit (tr_session * session, tr_variant *
settings)
+ else
+ tr_rpcSetWhitelistEnabled (s, boolVal);
+
++ key = TR_KEY_rpc_host_whitelist_enabled;
++
++ if (!tr_variantDictFindBool(settings, key, &boolVal))
++ {
++ missing_settings_key(key);
++ }
++ else
++ {
++ tr_rpcSetHostWhitelistEnabled(s, boolVal);
++ }
++
++ key = TR_KEY_rpc_host_whitelist;
++
++ if (!tr_variantDictFindStr(settings, key, &str, NULL) && str != NULL)
++ {
++ missing_settings_key(key);
++ }
++ else
++ {
++ tr_rpcSetHostWhitelist(s, str);
++ }
++
+ key = TR_KEY_rpc_authentication_required;
+ if (!tr_variantDictFindBool (settings, key, &boolVal))
+ missing_settings_key (key);
+diff --git a/libtransmission/rpc-server.h b/libtransmission/rpc-server.h
+index e0302c5ea..8c9e6b24e 100644
+--- a/libtransmission/rpc-server.h
++++ b/libtransmission/rpc-server.h
+@@ -49,6 +49,10 @@ void tr_rpcSetWhitelist (tr_rpc_server * server,
+
+ const char* tr_rpcGetWhitelist (const tr_rpc_server * server);
+
++void tr_rpcSetHostWhitelistEnabled(tr_rpc_server* server, bool isEnabled);
++
++void tr_rpcSetHostWhitelist(tr_rpc_server* server, char const* whitelist);
++
+ void tr_rpcSetPassword (tr_rpc_server * server,
+ const char * password);
+
+diff --git a/libtransmission/session.c b/libtransmission/session.c
+index 844cadba8..58b717913 100644
+--- a/libtransmission/session.c
++++ b/libtransmission/session.c
+@@ -359,6 +359,8 @@ tr_sessionGetDefaultSettings (tr_variant * d)
+ tr_variantDictAddStr (d, TR_KEY_rpc_username, "");
+ tr_variantDictAddStr (d, TR_KEY_rpc_whitelist,
TR_DEFAULT_RPC_WHITELIST);
+ tr_variantDictAddBool (d, TR_KEY_rpc_whitelist_enabled, true);
++ tr_variantDictAddStr(d, TR_KEY_rpc_host_whitelist,
TR_DEFAULT_RPC_HOST_WHITELIST);
++ tr_variantDictAddBool(d, TR_KEY_rpc_host_whitelist_enabled, true);
+ tr_variantDictAddInt (d, TR_KEY_rpc_port, atoi
(TR_DEFAULT_RPC_PORT_STR));
+ tr_variantDictAddStr (d, TR_KEY_rpc_url,
TR_DEFAULT_RPC_URL_STR);
+ tr_variantDictAddBool (d, TR_KEY_scrape_paused_torrents_enabled, true);
+diff --git a/libtransmission/transmission.h b/libtransmission/transmission.h
+index 4f76adfd6..e213a8f4e 100644
+--- a/libtransmission/transmission.h
++++ b/libtransmission/transmission.h
+@@ -123,6 +123,7 @@ const char* tr_getDefaultDownloadDir (void);
+ #define TR_DEFAULT_BIND_ADDRESS_IPV4 "0.0.0.0"
+ #define TR_DEFAULT_BIND_ADDRESS_IPV6 "::"
+ #define TR_DEFAULT_RPC_WHITELIST "127.0.0.1"
++#define TR_DEFAULT_RPC_HOST_WHITELIST ""
+ #define TR_DEFAULT_RPC_PORT_STR "9091"
+ #define TR_DEFAULT_RPC_URL_STR "/transmission/"
+ #define TR_DEFAULT_PEER_PORT_STR "51413"
+diff --git a/libtransmission/web.c b/libtransmission/web.c
+index ee495e9fc..c7f062730 100644
+--- a/libtransmission/web.c
++++ b/libtransmission/web.c
+@@ -594,6 +594,7 @@ tr_webGetResponseStr (long code)
+ case 415: return "Unsupported Media Type";
+ case 416: return "Requested Range Not Satisfiable";
+ case 417: return "Expectation Failed";
++ case 421: return "Misdirected Request";
+ case 500: return "Internal Server Error";
+ case 501: return "Not Implemented";
+ case 502: return "Bad Gateway";
--
2.15.1
--- End Message ---
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