44 lines
1.7 KiB
Diff
44 lines
1.7 KiB
Diff
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From f66dc643635518e53dfbe5262f814a64eec54e4a Mon Sep 17 00:00:00 2001
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From: Frediano Ziglio <fziglio@redhat.com>
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Date: Tue, 13 Dec 2016 14:40:10 +0000
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Subject: [PATCH] Prevent integer overflows in capability checks
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The limits for capabilities are specified using 32 bit unsigned integers.
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This could cause possible integer overflows causing buffer overflows.
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For instance the sum of num_common_caps and num_caps can be 0 avoiding
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additional checks.
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As the link message is now capped to 4096 and the capabilities are
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contained in the link message limit the capabilities to 1024
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(capabilities are expressed in number of uint32_t items).
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[Peter: fixes CVE-2016-9578]
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Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
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Acked-by: Christophe Fergeau <cfergeau@redhat.com>
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Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
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---
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server/reds.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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diff --git a/server/reds.c b/server/reds.c
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index 86a33d53..91504544 100644
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--- a/server/reds.c
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+++ b/server/reds.c
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@@ -2110,6 +2110,14 @@ static void reds_handle_read_link_done(void *opaque)
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link_mess->num_channel_caps = GUINT32_FROM_LE(link_mess->num_channel_caps);
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link_mess->num_common_caps = GUINT32_FROM_LE(link_mess->num_common_caps);
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+ /* Prevent DoS. Currently we defined only 13 capabilities,
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+ * I expect 1024 to be valid for quite a lot time */
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+ if (link_mess->num_channel_caps > 1024 || link_mess->num_common_caps > 1024) {
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+ reds_send_link_error(link, SPICE_LINK_ERR_INVALID_DATA);
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+ reds_link_free(link);
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+ return;
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+ }
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+
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num_caps = link_mess->num_common_caps + link_mess->num_channel_caps;
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caps = (uint32_t *)((uint8_t *)link_mess + link_mess->caps_offset);
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--
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2.11.0
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