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Description: sd-bus: if we receive an invalid dbus message, ignore and
proceeed
.
dbus-daemon might have a slightly different idea of what a valid msg is
than us (for example regarding valid msg and field sizes). Let's hence
try to proceed if we can and thus drop messages rather than fail the
connection if we fail to validate a message.
.
Hopefully the differences in what is considered valid are not visible
for real-life usecases, but are specific to exploit attempts only.
Author: Lennart Poettering <lennart@poettering.net>
Forwarded: other,https://github.com/systemd/systemd/pull/11708/
Patch from: systemd_237-3ubuntu10.13
For information see:
https://usn.ubuntu.com/3891-1/
https://git.launchpad.net/ubuntu/+source/systemd/commit/?h=applied/ubuntu/bionic-updates&id=d7584b894afcaa8a4a1abb69db2a9c81a6276e80
CVE: CVE-2019-6454
Upstream-Status: Backport
Signed-off-by: George McCollister <george.mccollister@gmail.com>
diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
index 30d6455b6f..441b4a816f 100644
--- a/src/libsystemd/sd-bus/bus-socket.c
+++ b/src/libsystemd/sd-bus/bus-socket.c
@@ -1072,7 +1072,7 @@ static int bus_socket_read_message_need(sd_bus *bus, size_t *need) {
}
static int bus_socket_make_message(sd_bus *bus, size_t size) {
- sd_bus_message *t;
+ sd_bus_message *t = NULL;
void *b;
int r;
@@ -1097,7 +1097,9 @@ static int bus_socket_make_message(sd_bus *bus, size_t size) {
bus->fds, bus->n_fds,
NULL,
&t);
- if (r < 0) {
+ if (r == -EBADMSG)
+ log_debug_errno(r, "Received invalid message from connection %s, dropping.", strna(bus->description));
+ else if (r < 0) {
free(b);
return r;
}
@@ -1108,7 +1110,8 @@ static int bus_socket_make_message(sd_bus *bus, size_t size) {
bus->fds = NULL;
bus->n_fds = 0;
- bus->rqueue[bus->rqueue_size++] = t;
+ if (t)
+ bus->rqueue[bus->rqueue_size++] = t;
return 1;
}
--
2.17.1
|
