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authorAndrey Konovalov <andreyknvl@google.com>2019-09-25 16:48:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-25 17:51:41 -0700
commit7d0325749a6c77b075424ab9de76bcb73a118430 (patch)
tree7158928c88f34ae5c07645c9a0a5614247882795
parented8a66b83269c27f7181c95b477da5d33fecfbc4 (diff)
downloadlinux-7d0325749a6c77b075424ab9de76bcb73a118430.tar.bz2
userfaultfd: untag user pointers
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. userfaultfd code use provided user pointers for vma lookups, which can only by done with untagged pointers. Untag user pointers in validate_range(). Link: http://lkml.kernel.org/r/cdc59ddd7011012ca2e689bc88c3b65b1ea7e413.1563904656.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Eric Auger <eric.auger@redhat.com> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Jens Wiklander <jens.wiklander@linaro.org> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/userfaultfd.c22
1 files changed, 12 insertions, 10 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index fe6d804a38dc..f9fd18670e22 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1272,21 +1272,23 @@ static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx,
}
static __always_inline int validate_range(struct mm_struct *mm,
- __u64 start, __u64 len)
+ __u64 *start, __u64 len)
{
__u64 task_size = mm->task_size;
- if (start & ~PAGE_MASK)
+ *start = untagged_addr(*start);
+
+ if (*start & ~PAGE_MASK)
return -EINVAL;
if (len & ~PAGE_MASK)
return -EINVAL;
if (!len)
return -EINVAL;
- if (start < mmap_min_addr)
+ if (*start < mmap_min_addr)
return -EINVAL;
- if (start >= task_size)
+ if (*start >= task_size)
return -EINVAL;
- if (len > task_size - start)
+ if (len > task_size - *start)
return -EINVAL;
return 0;
}
@@ -1336,7 +1338,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
goto out;
}
- ret = validate_range(mm, uffdio_register.range.start,
+ ret = validate_range(mm, &uffdio_register.range.start,
uffdio_register.range.len);
if (ret)
goto out;
@@ -1525,7 +1527,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister)))
goto out;
- ret = validate_range(mm, uffdio_unregister.start,
+ ret = validate_range(mm, &uffdio_unregister.start,
uffdio_unregister.len);
if (ret)
goto out;
@@ -1676,7 +1678,7 @@ static int userfaultfd_wake(struct userfaultfd_ctx *ctx,
if (copy_from_user(&uffdio_wake, buf, sizeof(uffdio_wake)))
goto out;
- ret = validate_range(ctx->mm, uffdio_wake.start, uffdio_wake.len);
+ ret = validate_range(ctx->mm, &uffdio_wake.start, uffdio_wake.len);
if (ret)
goto out;
@@ -1716,7 +1718,7 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
sizeof(uffdio_copy)-sizeof(__s64)))
goto out;
- ret = validate_range(ctx->mm, uffdio_copy.dst, uffdio_copy.len);
+ ret = validate_range(ctx->mm, &uffdio_copy.dst, uffdio_copy.len);
if (ret)
goto out;
/*
@@ -1772,7 +1774,7 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx,
sizeof(uffdio_zeropage)-sizeof(__s64)))
goto out;
- ret = validate_range(ctx->mm, uffdio_zeropage.range.start,
+ ret = validate_range(ctx->mm, &uffdio_zeropage.range.start,
uffdio_zeropage.range.len);
if (ret)
goto out;