The patch titled
Subject: mm: untag user pointers in mm/gup.c
has been added to the -mm tree. Its filename is
mm-untag-user-pointers-in-mm-gupc.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-untag-user-pointers-in-mm-gupc.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-untag-user-pointers-in-mm-gupc.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: mm: untag user pointers in mm/gup.c
This patch is a part of a series that extends kernel ABI to allow to pass
tagged user pointers (with the top byte set to something else other than
0x00) as syscall arguments.
mm/gup.c provides a kernel interface that accepts user addresses and
manipulates user pages directly (for example get_user_pages, that is used
by the futex syscall). Since a user can provided tagged addresses, we
need to handle this case.
Add untagging to gup.c functions that use user addresses for vma lookups.
Link: http://lkml.kernel.org/r/4731bddba3c938658c10ff4ed55cc01c60f4c8f8.1563904656.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Eric Auger <eric.auger@xxxxxxxxxx>
Cc: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Cc: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/gup.c~mm-untag-user-pointers-in-mm-gupc
+++ a/mm/gup.c
@@ -784,6 +784,8 @@ static long __get_user_pages(struct task
if (!nr_pages)
return 0;
+ start = untagged_addr(start);
+
VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
/*
@@ -946,6 +948,8 @@ int fixup_user_fault(struct task_struct
struct vm_area_struct *vma;
vm_fault_t ret, major = 0;
+ address = untagged_addr(address);
+
if (unlocked)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
lib-untag-user-pointers-in-strn_user.patch
mm-untag-user-pointers-passed-to-memory-syscalls.patch
mm-untag-user-pointers-in-mm-gupc.patch
mm-untag-user-pointers-in-get_vaddr_frames.patch
fs-namespace-untag-user-pointers-in-copy_mount_options.patch
userfaultfd-untag-user-pointers.patch
drm-amdgpu-untag-user-pointers.patch
drm-radeon-untag-user-pointers-in-radeon_gem_userptr_ioctl.patch
media-v4l2-core-untag-user-pointers-in-videobuf_dma_contig_user_get.patch
tee-shm-untag-user-pointers-in-tee_shm_register.patch
vfio-type1-untag-user-pointers-in-vaddr_get_pfn.patch
