Re: [PATCH][dizzy] qemu: CVE-2014-7840

[akuster808 <akuster808@gmail.com>]

On 8/18/15 1:45 AM, Sona Sarmadi wrote:
> 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
>
> Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>

Merged to staging,

Thanks,
Armin
> ---
>  .../recipes-devtools/qemu/qemu/CVE-2014-7840.patch | 57 ++++++++++++++++++++++
>  meta/recipes-devtools/qemu/qemu_2.1.0.bb           |  1 +
>  2 files changed, 58 insertions(+)
>  create mode 100644 meta/recipes-devtools/qemu/qemu/CVE-2014-7840.patch
>
> diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2014-7840.patch b/meta/recipes-devtools/qemu/qemu/CVE-2014-7840.patch
> new file mode 100644
> index 0000000..4f992ba
> --- /dev/null
> +++ b/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
> +
> diff --git a/meta/recipes-devtools/qemu/qemu_2.1.0.bb b/meta/recipes-devtools/qemu/qemu_2.1.0.bb
> index d0ce744..5e5ecf0 100644
> --- a/meta/recipes-devtools/qemu/qemu_2.1.0.bb
> +++ b/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"