[v2,0/4] arm64: kprobes: Update blacklist checking on arm64

Message

Masami Hiramatsu (Google) Jan. 15, 2019, 6:23 a.m. UTC

Hello,

Here is the v2 series of update of the kprobe blacklist
checking on arm64.

I found that some blacklist checking code were mis-placed in
arch_prepare_kprobe() and arch_within_kprobe_blacklist().
Since the blacklist just filters by symbol, smaller than the
symbol, like extable must be checked in arch_prepare_kprobe().
Also, all function (symbol) level check must be done by blacklist.

For arm64, it checks the extable entry address in blacklist
and exception/irqentry function in arch_prepare_kprobe().
And, RODATA check is unneeded since kernel/kprobes.c
already ensures the probe address is in kernel-text area.

In v2, I updated [1/4]'s description and added James'
Reviewed-by. Also, in this version, I added a patch which
uses arch_populate_kprobe_blacklist() instead of
arch_within_kprobe_blacklist() so that user can see the full
list of blacklisted symbols under the debugfs.

Changes in v2:
 - [1/4] change description so that it make clear and add
         James' Reviewed-by.
 - [4/4] new patch.

Thank you,

---

Masami Hiramatsu (4):
      arm64: kprobes: Move extable address check into arch_prepare_kprobe()
      arm64: kprobes: Remove unneeded RODATA check
      arm64: kprobes: Move exception_text check in blacklist
      arm64: kprobes: Use arch_populate_kprobe_blacklist()


 arch/arm64/kernel/probes/kprobes.c |   49 ++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 25 deletions(-)

--
Masami Hiramatsu (Linaro) <[e-mail]>

Comments

Will Deacon Jan. 16, 2019, 1:40 p.m. UTC | #1

Hi Masami,

On Tue, Jan 15, 2019 at 03:23:39PM +0900, Masami Hiramatsu wrote:
> Hello,
> 
> Here is the v2 series of update of the kprobe blacklist
> checking on arm64.
> 
> I found that some blacklist checking code were mis-placed in
> arch_prepare_kprobe() and arch_within_kprobe_blacklist().
> Since the blacklist just filters by symbol, smaller than the
> symbol, like extable must be checked in arch_prepare_kprobe().
> Also, all function (symbol) level check must be done by blacklist.
> 
> For arm64, it checks the extable entry address in blacklist
> and exception/irqentry function in arch_prepare_kprobe().
> And, RODATA check is unneeded since kernel/kprobes.c
> already ensures the probe address is in kernel-text area.
> 
> In v2, I updated [1/4]'s description and added James'
> Reviewed-by. Also, in this version, I added a patch which
> uses arch_populate_kprobe_blacklist() instead of
> arch_within_kprobe_blacklist() so that user can see the full
> list of blacklisted symbols under the debugfs.

Assuming these are targetting the arm64 tree, are you intending to get them
merged for 5.0?

Will

Masami Hiramatsu (Google) Jan. 19, 2019, 1:31 p.m. UTC | #2

Hi Will,

On Wed, 16 Jan 2019 13:40:07 +0000
Will Deacon <[e-mail]> wrote:

> Hi Masami,
> 
> On Tue, Jan 15, 2019 at 03:23:39PM +0900, Masami Hiramatsu wrote:
> > Hello,
> > 
> > Here is the v2 series of update of the kprobe blacklist
> > checking on arm64.
> > 
> > I found that some blacklist checking code were mis-placed in
> > arch_prepare_kprobe() and arch_within_kprobe_blacklist().
> > Since the blacklist just filters by symbol, smaller than the
> > symbol, like extable must be checked in arch_prepare_kprobe().
> > Also, all function (symbol) level check must be done by blacklist.
> > 
> > For arm64, it checks the extable entry address in blacklist
> > and exception/irqentry function in arch_prepare_kprobe().
> > And, RODATA check is unneeded since kernel/kprobes.c
> > already ensures the probe address is in kernel-text area.
> > 
> > In v2, I updated [1/4]'s description and added James'
> > Reviewed-by. Also, in this version, I added a patch which
> > uses arch_populate_kprobe_blacklist() instead of
> > arch_within_kprobe_blacklist() so that user can see the full
> > list of blacklisted symbols under the debugfs.
> 
> Assuming these are targetting the arm64 tree, are you intending to get them
> merged for 5.0?

No, I don't rush it, since these are not bugfix but just enhancements.
(User can see the blacklisted symbols precisely) If you think you are
easy to pick this to arm64/next, it is OK to me.

Thank you,