|
|
cc8519 |
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
|
|
|
88d513 |
From: Frediano Ziglio <fziglio@redhat.com>
|
|
|
88d513 |
Date: Mon, 28 Nov 2016 13:15:58 +0000
|
|
|
88d513 |
Subject: [PATCH] Prevent integer overflows in capability checks
|
|
|
88d513 |
|
|
|
88d513 |
The limits for capabilities are specified using 32 bit unsigned integers.
|
|
|
88d513 |
This could cause possible integer overflows causing buffer overflows.
|
|
|
88d513 |
For instance the sum of num_common_caps and num_caps can be 0 avoiding
|
|
|
88d513 |
additional checks.
|
|
|
88d513 |
As the link message is now capped to 4096 and the capabilities are
|
|
|
88d513 |
contained in the link message, this commit limits the capabilities
|
|
|
88d513 |
to 1024 (capabilities are expressed in number of uint32_t items).
|
|
|
88d513 |
|
|
|
88d513 |
Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
|
|
|
88d513 |
---
|
|
|
cc8519 |
server/reds.c | 8 ++++++++
|
|
|
cc8519 |
1 file changed, 8 insertions(+)
|
|
|
88d513 |
|
|
|
88d513 |
diff --git a/server/reds.c b/server/reds.c
|
|
|
cc8519 |
index 86a33d5..c639aa3 100644
|
|
|
88d513 |
--- a/server/reds.c
|
|
|
88d513 |
+++ b/server/reds.c
|
|
|
cc8519 |
@@ -2113,6 +2113,14 @@ static void reds_handle_read_link_done(void *opaque)
|
|
|
cc8519 |
num_caps = link_mess->num_common_caps + link_mess->num_channel_caps;
|
|
|
cc8519 |
caps = (uint32_t *)((uint8_t *)link_mess + link_mess->caps_offset);
|
|
|
88d513 |
|
|
|
88d513 |
+ /* Prevent integer overflows. Currently we defined only 13 capabilities,
|
|
|
88d513 |
+ * I expect 1024 to be valid for quite a lot time */
|
|
|
88d513 |
+ if (link_mess->num_channel_caps > 1024 || link_mess->num_common_caps > 1024) {
|
|
|
88d513 |
+ reds_send_link_error(link, SPICE_LINK_ERR_INVALID_DATA);
|
|
|
88d513 |
+ reds_link_free(link);
|
|
|
88d513 |
+ return;
|
|
|
88d513 |
+ }
|
|
|
88d513 |
+
|
|
|
88d513 |
if (num_caps && (num_caps * sizeof(uint32_t) + link_mess->caps_offset >
|
|
|
88d513 |
link->link_header.size ||
|
|
|
88d513 |
link_mess->caps_offset < sizeof(*link_mess))) {
|