[Qemu-stable] 答复: [Qemu-devel] [PATCH 25/53] i8254: fix out-of-bounds memory access in pit_ioport_read()

[lidonglin]

Which qemu versions does this CVE affect ? 


Li Donglin
> 发件人: address@hidden
> [mailto:address@hidden 代表
> Michael Roth
> 发送时间: 2015年7月30日 19:33
> 收件人: address@hidden
> 抄送: Paolo Bonzini; Petr Matousek; address@hidden
> 主题: [Qemu-devel] [PATCH 25/53] i8254: fix out-of-bounds memory access in
> pit_ioport_read()
> 
> From: Petr Matousek <address@hidden>
> 
> Due converting PIO to the new memory read/write api we no longer provide
> separate I/O region lenghts for read and write operations. As a result, 
> reading
> from PIT Mode/Command register will end with accessing
> pit->channels with invalid index.
> 
> Fix this by ignoring read from the Mode/Command register.
> 
> This is CVE-2015-3214.
> 
> Reported-by: Matt Tait <address@hidden>
> Fixes: 0505bcdec8228d8de39ab1a02644e71999e7c052
> Cc: address@hidden
> Signed-off-by: Petr Matousek <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden> (cherry picked from
> commit d4862a87e31a51de9eb260f25c9e99a75efe3235)
> Signed-off-by: Michael Roth <address@hidden>
> ---
>  hw/timer/i8254.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/hw/timer/i8254.c b/hw/timer/i8254.c index 3450c98..9b65a33
> 100644
> --- a/hw/timer/i8254.c
> +++ b/hw/timer/i8254.c
> @@ -196,6 +196,12 @@ static uint64_t pit_ioport_read(void *opaque,
> hwaddr addr,
>      PITChannelState *s;
> 
>      addr &= 3;
> +
> +    if (addr == 3) {
> +        /* Mode/Command register is write only, read is ignored */
> +        return 0;
> +    }
> +
>      s = &pit->channels[addr];
>      if (s->status_latched) {
>          s->status_latched = 0;
> --
> 1.9.1
>