On Thu, Aug 15, 2019 at 5:44 PM Catalin Marinas <catalin.marinas@xxxxxxx> wrote:
>
> There isn't a good reason to differentiate between the user address
> space layout modification syscalls and the other memory
> permission/attributes ones (e.g. mprotect, madvise) w.r.t. the tagged
> address ABI. Untag the user addresses on entry to these functions.
>
> Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Acked-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> ---
> mm/mmap.c | 5 +++++
> mm/mremap.c | 6 +-----
> 2 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 7e8c3e8ae75f..b766b633b7ae 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -201,6 +201,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
> bool downgraded = false;
> LIST_HEAD(uf);
>
> + brk = untagged_addr(brk);
> +
> if (down_write_killable(&mm->mmap_sem))
> return -EINTR;
>
> @@ -1573,6 +1575,8 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
> struct file *file = NULL;
> unsigned long retval;
>
> + addr = untagged_addr(addr);
> +
> if (!(flags & MAP_ANONYMOUS)) {
> audit_mmap_fd(fd, flags);
> file = fget(fd);
> @@ -2874,6 +2878,7 @@ EXPORT_SYMBOL(vm_munmap);
>
> SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
> {
> + addr = untagged_addr(addr);
> profile_munmap(addr);
> return __vm_munmap(addr, len, true);
> }
> diff --git a/mm/mremap.c b/mm/mremap.c
> index 64c9a3b8be0a..1fc8a29fbe3f 100644
> --- a/mm/mremap.c
> +++ b/mm/mremap.c
> @@ -606,12 +606,8 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
> LIST_HEAD(uf_unmap_early);
> LIST_HEAD(uf_unmap);
>
> - /*
> - * Architectures may interpret the tag passed to mmap as a background
> - * colour for the corresponding vma. For mremap we don't allow tagged
> - * new_addr to preserve similar behaviour to mmap.
> - */
> addr = untagged_addr(addr);
> + new_addr = untagged_addr(new_addr);
>
> if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
> return ret;
