From bace3cd819798571189671b68590adff3fd40997 Mon Sep 17 00:00:00 2001 From: Pekka Paalanen Date: Wed, 6 Mar 2019 13:42:23 +0200 Subject: [PATCH] connection: fix demarshal of invalid header The size argument to wl_connection_demarshal() is taken from the message by the caller wl_client_connection_data(), therefore 'size' is untrusted data controllable by a Wayland client. The size should always be at least the header size, otherwise the header is invalid. If the size is smaller than header size, it leads to reading past the end of allocated memory. Furthermore if size is zero, wl_closure_init() changes behaviour and leaves num_arrays uninitialized, leading to access of arbitrary memory. Check that 'size' fits at least the header. The space for arguments is already properly checked. This makes the request_bogus_size test free of errors under Valgrind. Fixes: https://gitlab.freedesktop.org/wayland/wayland/issues/52 Signed-off-by: Pekka Paalanen Reviewed-by: Simon Ser --- src/connection.c | 8 ++++++++ tests/connection-test.c | 2 +- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/src/connection.c b/src/connection.c index 474c97b..7fba999 100644 --- a/src/connection.c +++ b/src/connection.c @@ -695,6 +695,14 @@ wl_connection_demarshal(struct wl_connection *connection, struct wl_closure *closure; struct wl_array *array_extra; + /* Space for sender_id and opcode */ + if (size < 2 * sizeof *p) { + wl_log("message too short, invalid header\n"); + wl_connection_consume(connection, size); + errno = EINVAL; + return NULL; + } + closure = wl_closure_init(message, size, &num_arrays, NULL); if (closure == NULL) { wl_connection_consume(connection, size); diff --git a/tests/connection-test.c b/tests/connection-test.c index c3496e6..a06a3cc 100644 --- a/tests/connection-test.c +++ b/tests/connection-test.c @@ -798,7 +798,7 @@ expect_error_recv(int sockfd, uint32_t expected_error) * However, running under Valgrind would point out invalid reads and use of * uninitialized values. */ -FAIL_TEST(request_bogus_size) +TEST(request_bogus_size) { struct wl_display *display; struct wl_client *client; -- 2.7.4