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From 6986f7c62b38d90992bd8f7c178325fc1e31d7fe Mon Sep 17 00:00:00 2001
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Message-Id: <6986f7c62b38d90992bd8f7c178325fc1e31d7fe.1418766606.git.jen@redhat.com>
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In-Reply-To: <6f81b4847eb68ebdf54a8f1a771e19d112d74152.1418766606.git.jen@redhat.com>
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References: <6f81b4847eb68ebdf54a8f1a771e19d112d74152.1418766606.git.jen@redhat.com>
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From: Amos Kong <akong@redhat.com>
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Date: Mon, 8 Dec 2014 14:53:34 -0600
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Subject: [CHANGE 31/31] migration: fix parameter validation on ram load
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 (CVE-2014-7840)
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To: rhvirt-patches@redhat.com,
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    jen@redhat.com
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RH-Author: Amos Kong <akong@redhat.com>
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Message-id: <1418050414-25145-1-git-send-email-akong@redhat.com>
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Patchwork-id: 62762
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O-Subject: [RHEL-7.1 qemu-kvm PATCH] migration: fix parameter validation on ram load (CVE-2014-7840)
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Bugzilla: 1163078
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RH-Acked-by: Juan Quintela <quintela@redhat.com>
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RH-Acked-by: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
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RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
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From: Michael S. Tsirkin <mst@redhat.com>
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During migration, the values read from migration stream during ram load
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are not validated. Especially offset in host_from_stream_offset() and
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also the length of the writes in the callers of said function.
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To fix this, we need to make sure that the [offset, offset + length]
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range fits into one of the allocated memory regions.
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Validating addr < len should be sufficient since data seems to always be
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managed in TARGET_PAGE_SIZE chunks.
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Fixes: CVE-2014-7840
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Note: follow-up patches add extra checks on each block->host access.
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
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Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Signed-off-by: Amit Shah <amit.shah@redhat.com>
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(backported from commit 0be839a2701369f669532ea5884c15bead1c6e08)
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Conflict was caused by different error reporting.
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Signed-off-by: Amos Kong <akong@redhat.com>
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Signed-off-by: Jeff E. Nelson <jen@redhat.com>
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---
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 arch_init.c | 5 +++--
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 1 file changed, 3 insertions(+), 2 deletions(-)
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diff --git a/arch_init.c b/arch_init.c
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index 0c2bde9..4c3d3b5 100644
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--- a/arch_init.c
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+++ b/arch_init.c
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@@ -979,7 +979,7 @@ static inline void *host_from_stream_offset(QEMUFile *f,
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     uint8_t len;
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     if (flags & RAM_SAVE_FLAG_CONTINUE) {
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-        if (!block) {
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+        if (!block || block->length <= offset) {
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             fprintf(stderr, "Ack, bad migration stream!\n");
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             return NULL;
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         }
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@@ -992,8 +992,9 @@ static inline void *host_from_stream_offset(QEMUFile *f,
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     id[len] = 0;
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     QTAILQ_FOREACH(block, &ram_list.blocks, next) {
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-        if (!strncmp(id, block->idstr, sizeof(id)))
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+        if (!strncmp(id, block->idstr, sizeof(id)) && block->length > offset) {
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             return memory_region_get_ram_ptr(block->mr) + offset;
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+        }
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     }
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     fprintf(stderr, "Can't find block %s!\n", id);
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-- 
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2.1.0
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