Comment 14 for bug 1783362

Laurent Vivier <email address hidden> writes:

> Le 30/07/2018 à 15:43, Alex Bennée a écrit:
>> I've slightly re-organised the check to more closely match the
>> sequence that the kernel uses in do_mmap(). We check for both the zero
>> case (EINVAL) and the overflow length case (ENOMEM).
>>
>> Signed-off-by: Alex Bennée <email address hidden>
>> Cc: umarcor <email address hidden>
>>
>> ---
>> v2
>> - add comment on overflow
>> ---
>> linux-user/mmap.c | 15 ++++++++++++---
>> 1 file changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
>> index d0c50e4888..41e0983ce8 100644
>> --- a/linux-user/mmap.c
>> +++ b/linux-user/mmap.c
>> @@ -391,14 +391,23 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
>> }
>> #endif
>>
>> - if (offset & ~TARGET_PAGE_MASK) {
>> + if (!len) {
>> errno = EINVAL;
>> goto fail;
>> }
>>
>> + /* Also check for overflows... */
>> len = TARGET_PAGE_ALIGN(len);
>> - if (len == 0)
>> - goto the_end;
>> + if (!len) {
>> + errno = ENOMEM;
>> + goto fail;
>> + }
>> +
>> + if (offset & ~TARGET_PAGE_MASK) {
>> + errno = EINVAL;
>> + goto fail;
>> + }
>> +
>> real_start = start & qemu_host_page_mask;
>> host_offset = offset & qemu_host_page_mask;
>>
>>
>
> Reviewed-by: Laurent Vivier <email address hidden>

Are you going to take this via your queue or do you want me to re-post
with the r-b?

--
Alex Bennée