qemu: CVE-2014-7840

Fixes insufficient parameter validation during ram load

Reference
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-7840

Upstream commit:
http://git.qemu.org/?p=qemu.git;a=commit;
h=0be839a2701369f669532ea5884c15bead1c6e08

(From OE-Core rev: 0bd4b0c7ede8a52559e4bf05085a3f0d46a0a280)

Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/qemu/qemu/CVE-2014-7840.patch

@@ -0,0 +1,57 @@
+From 0be839a2701369f669532ea5884c15bead1c6e08 Mon Sep 17 00:00:00 2001
+From: "Michael S. Tsirkin" <mst@redhat.com>
+Date: Wed, 12 Nov 2014 11:44:39 +0200
+Subject: [PATCH] migration: fix parameter validation on ram load
+
+During migration, the values read from migration stream during ram load
+are not validated. Especially offset in host_from_stream_offset() and
+also the length of the writes in the callers of said function.
+
+To fix this, we need to make sure that the [offset, offset + length]
+range fits into one of the allocated memory regions.
+
+Validating addr < len should be sufficient since data seems to always be
+managed in TARGET_PAGE_SIZE chunks.
+
+Fixes: CVE-2014-7840
+
+Upstream-Status: Backport
+
+Note: follow-up patches add extra checks on each block->host access.
+
+Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
+Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
+Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
+Signed-off-by: Amit Shah <amit.shah@redhat.com>
+Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
+---
+ arch_init.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/arch_init.c b/arch_init.c
+index 88a5ba0..593a990 100644
+--- a/arch_init.c
++++ b/arch_init.c
+@@ -1006,7 +1006,7 @@ static inline void *host_from_stream_offset(QEMUFile *f,
+     uint8_t len;
+ 
+     if (flags & RAM_SAVE_FLAG_CONTINUE) {
+-        if (!block) {
++        if (!block || block->length <= offset) {
+             error_report("Ack, bad migration stream!");
+             return NULL;
+         }
+@@ -1019,8 +1019,9 @@ static inline void *host_from_stream_offset(QEMUFile *f,
+     id[len] = 0;
+ 
+     QTAILQ_FOREACH(block, &ram_list.blocks, next) {
+-        if (!strncmp(id, block->idstr, sizeof(id)))
++        if (!strncmp(id, block->idstr, sizeof(id)) && block->length > offset) {
+             return memory_region_get_ram_ptr(block->mr) + offset;
++        }
+     }
+ 
+     error_report("Can't find block %s!", id);
+-- 
+1.9.1
+

meta/recipes-devtools/qemu/qemu_2.1.0.bb

@@ -8,6 +8,7 @@ SRC_URI += "file://configure-fix-Darwin-target-detection.patch \
             file://Qemu-Arm-versatilepb-Add-memory-size-checking.patch \
             file://0001-Back-porting-security-fix-CVE-2014-5388.patch \
             file://qemu-CVE-2015-3456.patch \
+            file://CVE-2014-7840.patch \
             "
 SRC_URI_prepend = "http://wiki.qemu-project.org/download/${BP}.tar.bz2"
 SRC_URI[md5sum] = "6726977292b448cbc7f89998fac6983b"