diff mbox series

[10/11] linux-user/syscall: verify recvfrom(addr) is user-writable

Message ID 20180124130126.20871-11-f4bug@amsat.org
State New
Headers show
Series linux-user: improve NETLINK strace | expand

Commit Message

Philippe Mathieu-Daudé Jan. 24, 2018, 1:01 p.m. UTC 
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 linux-user/syscall.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Laurent Vivier Feb. 15, 2018, 5:27 p.m. UTC | #1 
Le 24/01/2018 à 14:01, Philippe Mathieu-Daudé a écrit :
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  linux-user/syscall.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 11c9116c4a..b6b9beca5b 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -4040,6 +4040,11 @@ 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));
> 

Even if host_to_target_sockaddr() will do the check before copying data
to the target, I think it is good to check this before reading the data, so:

Reviewed-by: Laurent Vivier <laurent@vivier.eu>

Thanks,
Laurent
diff mbox series

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 11c9116c4a..b6b9beca5b 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -4040,6 +4040,11 @@  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));