[PATCH v12 07/13] fs, arm64: untag user pointers in fs/userfaultfd.c
From: Andrey Konovalov <hidden>
Date: 2019-03-18 17:18:17
Also in:
bpf, linux-arch, linux-doc, linux-kselftest, linux-mm, lkml, netdev
Subsystem:
filesystems (vfs and infrastructure), memory management - userfaultfd, the rest · Maintainers:
Alexander Viro, Christian Brauner, Andrew Morton, Mike Rapoport, Linus Torvalds
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 <redacted> --- 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)
--
2.21.0.225.g810b269d1ac-goog
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