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@google.com --- fs/userfaultfd.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 89800fc7dc9d..a3b70e0d9756 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1320,6 +1320,9 @@ 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) @@ -1507,6 +1510,8 @@ 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)