Le 27/03/2021 à 03:11, Zach Reizner a écrit :
> The kernel allows a NULL msg in recvfrom so that he size of the next
> message may be queried before allocating a correctly sized buffer. This
> change allows the syscall translator to pass along the NULL msg pointer
> instead of returning early with EFAULT.
>
> Signed-off-by: Zach Reizner <za...@google.com>
> ---
> v2:
> - return -TARGET_EFAULT on non-null invalid msg pointer
>
> linux-user/syscall.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 1e508576c7..294779c86f 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -3679,9 +3679,14 @@ static abi_long do_recvfrom(int fd, abi_ulong
> msg, size_t len, int flags,
> void *host_msg;
> abi_long ret;
>
> - host_msg = lock_user(VERIFY_WRITE, msg, len, 0);
> - if (!host_msg)
> - return -TARGET_EFAULT;
> + if (!msg) {
> + host_msg = NULL;
> + } else {
> + host_msg = lock_user(VERIFY_WRITE, msg, len, 0);
> + if (!host_msg) {
> + return -TARGET_EFAULT;
> + }
> + }
> if (target_addr) {
> if (get_user_u32(addrlen, target_addrlen)) {
> ret = -TARGET_EFAULT;
>
Reviewed-by: Laurent Vivier <laur...@vivier.eu>
