linux.git/mm/maccess.c, branch v5.8

maccess: rename probe_user_{read,write} to copy_{from,to}_user_nofault

2020-06-17T17:57:41+00:00

Better describe what these functions do.

Suggested-by: Linus Torvalds 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Linus Torvalds

maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

2020-06-17T17:57:41+00:00

Better describe what these functions do.

Suggested-by: Linus Torvalds 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Linus Torvalds

maccess: return -ERANGE when probe_kernel_read() fails

2020-06-09T16:39:16+00:00

Allow the callers to distinguish a real unmapped address vs a range
that can't be probed.

Suggested-by: Masami Hiramatsu 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Reviewed-by: Masami Hiramatsu 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20200521152301.2587579-24-hch@lst.de
Signed-off-by: Linus Torvalds

maccess: allow architectures to provide kernel probing directly

2020-06-09T16:39:15+00:00

Provide alternative versions of probe_kernel_read, probe_kernel_write
and strncpy_from_kernel_unsafe that don't need set_fs magic, but instead
use arch hooks that are modelled after unsafe_{get,put}_user to access
kernel memory in an exception safe way.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Masami Hiramatsu 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20200521152301.2587579-19-hch@lst.de
Signed-off-by: Linus Torvalds

maccess: move user access routines together

2020-06-09T16:39:15+00:00

Move kernel access vs user access routines together to ease upcoming
ifdefs.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Masami Hiramatsu 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20200521152301.2587579-18-hch@lst.de
Signed-off-by: Linus Torvalds

maccess: always use strict semantics for probe_kernel_read

2020-06-09T16:39:15+00:00

Except for historical confusion in the kprobes/uprobes and bpf tracers,
which has been fixed now, there is no good reason to ever allow user
memory accesses from probe_kernel_read.  Switch probe_kernel_read to only
read from kernel memory.

[akpm@linux-foundation.org: update it for "mm, dump_page(): do not crash with invalid mapping pointer"]

Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Masami Hiramatsu 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20200521152301.2587579-17-hch@lst.de
Signed-off-by: Linus Torvalds

maccess: remove strncpy_from_unsafe

2020-06-09T16:39:15+00:00

All users are gone now.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Masami Hiramatsu 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20200521152301.2587579-16-hch@lst.de
Signed-off-by: Linus Torvalds

maccess: unify the probe kernel arch hooks

2020-06-09T16:39:15+00:00

Currently architectures have to override every routine that probes
kernel memory, which includes a pure read and strcpy, both in strict
and not strict variants.  Just provide a single arch hooks instead to
make sure all architectures cover all the cases.

[akpm@linux-foundation.org: fix !CONFIG_X86_64 build]

Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Masami Hiramatsu 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20200521152301.2587579-11-hch@lst.de
Signed-off-by: Linus Torvalds

maccess: remove probe_read_common and probe_write_common

2020-06-09T16:39:15+00:00

Each of the helpers has just two callers, which also different in
dealing with kernel or userspace pointers.  Just open code the logic
in the callers.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Masami Hiramatsu 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20200521152301.2587579-10-hch@lst.de
Signed-off-by: Linus Torvalds

maccess: rename strnlen_unsafe_user to strnlen_user_nofault

2020-06-09T16:39:15+00:00

This matches the naming of strnlen_user, and also makes it more clear
what the function is supposed to do.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Masami Hiramatsu 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20200521152301.2587579-9-hch@lst.de
Signed-off-by: Linus Torvalds