This patch is a part of a series that extends arm64 kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. userfaultfd_register() and userfaultfd_unregister() use provided user pointers for vma lookups, which can only by done with untagged pointers. Untag user pointers in these functions. Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> --- fs/userfaultfd.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index f5de1e726356..fdee0db0e847 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1325,6 +1325,9 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, goto out; } + uffdio_register.range.start = + untagged_addr(uffdio_register.range.start); + ret = validate_range(mm, uffdio_register.range.start, uffdio_register.range.len); if (ret) @@ -1514,6 +1517,8 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister))) goto out; + uffdio_unregister.start = untagged_addr(uffdio_unregister.start); + ret = validate_range(mm, uffdio_unregister.start, uffdio_unregister.len); if (ret) -- 2.21.0.593.g511ec345e18-goog
