aboutsummaryrefslogtreecommitdiff
path: root/gnu/packages/patches/dbus-CVE-2019-12749.patch
diff options
context:
space:
mode:
Diffstat (limited to 'gnu/packages/patches/dbus-CVE-2019-12749.patch')
-rw-r--r--gnu/packages/patches/dbus-CVE-2019-12749.patch116
1 files changed, 0 insertions, 116 deletions
diff --git a/gnu/packages/patches/dbus-CVE-2019-12749.patch b/gnu/packages/patches/dbus-CVE-2019-12749.patch
deleted file mode 100644
index 12106f4589..0000000000
--- a/gnu/packages/patches/dbus-CVE-2019-12749.patch
+++ /dev/null
@@ -1,116 +0,0 @@
-From 47b1a4c41004bf494b87370987b222c934b19016 Mon Sep 17 00:00:00 2001
-From: Simon McVittie <smcv@collabora.com>
-Date: Thu, 30 May 2019 12:53:03 +0100
-Subject: [PATCH] auth: Reject DBUS_COOKIE_SHA1 for users other than the server
- owner
-
-The DBUS_COOKIE_SHA1 authentication mechanism aims to prove ownership
-of a shared home directory by having the server write a secret "cookie"
-into a .dbus-keyrings subdirectory of the desired identity's home
-directory with 0700 permissions, and having the client prove that it can
-read the cookie. This never actually worked for non-malicious clients in
-the case where server uid != client uid (unless the server and client
-both have privileges, such as Linux CAP_DAC_OVERRIDE or traditional
-Unix uid 0) because an unprivileged server would fail to write out the
-cookie, and an unprivileged client would be unable to read the resulting
-file owned by the server.
-
-Additionally, since dbus 1.7.10 we have checked that ~/.dbus-keyrings
-is owned by the uid of the server (a side-effect of a check added to
-harden our use of XDG_RUNTIME_DIR), further ruling out successful use
-by a non-malicious client with a uid differing from the server's.
-
-Joe Vennix of Apple Information Security discovered that the
-implementation of DBUS_COOKIE_SHA1 was susceptible to a symbolic link
-attack: a malicious client with write access to its own home directory
-could manipulate a ~/.dbus-keyrings symlink to cause the DBusServer to
-read and write in unintended locations. In the worst case this could
-result in the DBusServer reusing a cookie that is known to the
-malicious client, and treating that cookie as evidence that a subsequent
-client connection came from an attacker-chosen uid, allowing
-authentication bypass.
-
-This is mitigated by the fact that by default, the well-known system
-dbus-daemon (since 2003) and the well-known session dbus-daemon (in
-stable releases since dbus 1.10.0 in 2015) only accept the EXTERNAL
-authentication mechanism, and as a result will reject DBUS_COOKIE_SHA1
-at an early stage, before manipulating cookies. As a result, this
-vulnerability only applies to:
-
-* system or session dbus-daemons with non-standard configuration
-* third-party dbus-daemon invocations such as at-spi2-core (although
- in practice at-spi2-core also only accepts EXTERNAL by default)
-* third-party uses of DBusServer such as the one in Upstart
-
-Avoiding symlink attacks in a portable way is difficult, because APIs
-like openat() and Linux /proc/self/fd are not universally available.
-However, because DBUS_COOKIE_SHA1 already doesn't work in practice for
-a non-matching uid, we can solve this vulnerability in an easier way
-without regressions, by rejecting it early (before looking at
-~/.dbus-keyrings) whenever the requested identity doesn't match the
-identity of the process hosting the DBusServer.
-
-Signed-off-by: Simon McVittie <smcv@collabora.com>
-Closes: https://gitlab.freedesktop.org/dbus/dbus/issues/269
-Closes: CVE-2019-12749
----
- dbus/dbus-auth.c | 32 ++++++++++++++++++++++++++++++++
- 1 file changed, 32 insertions(+)
-
-diff --git a/dbus/dbus-auth.c b/dbus/dbus-auth.c
-index 37d8d4c9..7390a9d5 100644
---- a/dbus/dbus-auth.c
-+++ b/dbus/dbus-auth.c
-@@ -529,6 +529,7 @@ sha1_handle_first_client_response (DBusAuth *auth,
- DBusString tmp2;
- dbus_bool_t retval = FALSE;
- DBusError error = DBUS_ERROR_INIT;
-+ DBusCredentials *myself = NULL;
-
- _dbus_string_set_length (&auth->challenge, 0);
-
-@@ -565,6 +566,34 @@ sha1_handle_first_client_response (DBusAuth *auth,
- return FALSE;
- }
-
-+ myself = _dbus_credentials_new_from_current_process ();
-+
-+ if (myself == NULL)
-+ goto out;
-+
-+ if (!_dbus_credentials_same_user (myself, auth->desired_identity))
-+ {
-+ /*
-+ * DBUS_COOKIE_SHA1 is not suitable for authenticating that the
-+ * client is anyone other than the user owning the process
-+ * containing the DBusServer: we probably aren't allowed to write
-+ * to other users' home directories. Even if we can (for example
-+ * uid 0 on traditional Unix or CAP_DAC_OVERRIDE on Linux), we
-+ * must not, because the other user controls their home directory,
-+ * and could carry out symlink attacks to make us read from or
-+ * write to unintended locations. It's difficult to avoid symlink
-+ * attacks in a portable way, so we just don't try. This isn't a
-+ * regression, because DBUS_COOKIE_SHA1 never worked for other
-+ * users anyway.
-+ */
-+ _dbus_verbose ("%s: client tried to authenticate as \"%s\", "
-+ "but that doesn't match this process",
-+ DBUS_AUTH_NAME (auth),
-+ _dbus_string_get_const_data (data));
-+ retval = send_rejected (auth);
-+ goto out;
-+ }
-+
- /* we cache the keyring for speed, so here we drop it if it's the
- * wrong one. FIXME caching the keyring here is useless since we use
- * a different DBusAuth for every connection.
-@@ -679,6 +708,9 @@ sha1_handle_first_client_response (DBusAuth *auth,
- _dbus_string_zero (&tmp2);
- _dbus_string_free (&tmp2);
-
-+ if (myself != NULL)
-+ _dbus_credentials_unref (myself);
-+
- return retval;
- }
-