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Fix CVE-2020-12049:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-12049
https://lists.freedesktop.org/archives/ftp-release/2020-June/000753.html
Taken from upstream:
https://gitlab.freedesktop.org/dbus/dbus/-/commit/272d484283883fa9ff95b69d924fff6cd34842f5
diff --git a/dbus/dbus-sysdeps-unix.c b/dbus/dbus-sysdeps-unix.c
--- a/dbus/dbus-sysdeps-unix.c
+++ b/dbus/dbus-sysdeps-unix.c
@@ -435,18 +435,6 @@ _dbus_read_socket_with_unix_fds (DBusSocket fd,
struct cmsghdr *cm;
dbus_bool_t found = FALSE;
- if (m.msg_flags & MSG_CTRUNC)
- {
- /* Hmm, apparently the control data was truncated. The bad
- thing is that we might have completely lost a couple of fds
- without chance to recover them. Hence let's treat this as a
- serious error. */
-
- errno = ENOSPC;
- _dbus_string_set_length (buffer, start);
- return -1;
- }
-
for (cm = CMSG_FIRSTHDR(&m); cm; cm = CMSG_NXTHDR(&m, cm))
if (cm->cmsg_level == SOL_SOCKET && cm->cmsg_type == SCM_RIGHTS)
{
@@ -501,6 +489,26 @@ _dbus_read_socket_with_unix_fds (DBusSocket fd,
if (!found)
*n_fds = 0;
+ if (m.msg_flags & MSG_CTRUNC)
+ {
+ unsigned int i;
+
+ /* Hmm, apparently the control data was truncated. The bad
+ thing is that we might have completely lost a couple of fds
+ without chance to recover them. Hence let's treat this as a
+ serious error. */
+
+ /* We still need to close whatever fds we *did* receive,
+ * otherwise they'll never get closed. (CVE-2020-12049) */
+ for (i = 0; i < *n_fds; i++)
+ close (fds[i]);
+
+ *n_fds = 0;
+ errno = ENOSPC;
+ _dbus_string_set_length (buffer, start);
+ return -1;
+ }
+
/* put length back (doesn't actually realloc) */
_dbus_string_set_length (buffer, start + bytes_read);
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