Comment 6 for bug 1783362

Le 26/07/2018 à 15:29, Alex Bennée a écrit :
> I've slightly re-organised the check to more closely match the
> sequence that the kernel uses in do_mmap().
>
> Signed-off-by: Alex Bennée <email address hidden>
> Cc: umarcor <email address hidden>
> ---
> linux-user/mmap.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
> index d0c50e4888..3ef69fa2d0 100644
> --- a/linux-user/mmap.c
> +++ b/linux-user/mmap.c
> @@ -391,14 +391,22 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
> }
> #endif
>
> - if (offset & ~TARGET_PAGE_MASK) {
> + if (!len) {
> errno = EINVAL;
> goto fail;
> }
>
> len = TARGET_PAGE_ALIGN(len);
> - if (len == 0)
> - goto the_end;
> + if (!len) {
> + errno = EINVAL;
> + goto fail;
> + }

Why do you check twice len?
TARGET_PAGE_ALIGN() rounds up the value, so if it was not 0, it cannot
be now.

Thanks,
Laurent