Re: [Qemu-devel] [PATCH v3 01/13] linux-user/syscall: Verify recvfrom(addr) is user-writable

[Laurent Vivier <laurent@vivier.eu>]

Le 02/07/2018 à 19:50, Philippe Mathieu-Daudé a écrit :
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Tested-By: Guido Günther <agx@sigxcpu.org>
> Reviewed-by: Laurent Vivier <laurent@vivier.eu>
> ---
>  linux-user/syscall.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 2117fb13b4..ad40682cee 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -4154,6 +4154,11 @@ static abi_long do_recvfrom(int fd, abi_ulong msg, size_t len, int flags,
>              ret = -TARGET_EINVAL;
>              goto fail;
>          }
> +        if (!access_ok(VERIFY_WRITE, target_addr, addrlen)) {
> +            ret = -TARGET_EFAULT;
> +            goto fail;
> +        }
> +
>          addr = alloca(addrlen);
>          ret = get_errno(safe_recvfrom(fd, host_msg, len, flags,
>                                        addr, &addrlen));
> 

This patch breaks the test recvfrom01 of the Linux Test Project.

Laurent