This is a note to let you know that I've just added the patch titled
ARM: 9071/1: uprobes: Don't hook on thumb instructions
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-9071-1-uprobes-don-t-hook-on-thumb-instructions.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d2f7eca60b29006285d57c7035539e33300e89e5 Mon Sep 17 00:00:00 2001
From: Fredrik Strupe <fredrik@xxxxxxxxxx>
Date: Mon, 5 Apr 2021 21:52:05 +0100
Subject: ARM: 9071/1: uprobes: Don't hook on thumb instructions
From: Fredrik Strupe <fredrik@xxxxxxxxxx>
commit d2f7eca60b29006285d57c7035539e33300e89e5 upstream.
Since uprobes is not supported for thumb, check that the thumb bit is
not set when matching the uprobes instruction hooks.
The Arm UDF instructions used for uprobes triggering
(UPROBE_SWBP_ARM_INSN and UPROBE_SS_ARM_INSN) coincidentally share the
same encoding as a pair of unallocated 32-bit thumb instructions (not
UDF) when the condition code is 0b1111 (0xf). This in effect makes it
possible to trigger the uprobes functionality from thumb, and at that
using two unallocated instructions which are not permanently undefined.
Signed-off-by: Fredrik Strupe <fredrik@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: c7edc9e326d5 ("ARM: add uprobes support")
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/probes/uprobes/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/arm/probes/uprobes/core.c
+++ b/arch/arm/probes/uprobes/core.c
@@ -204,7 +204,7 @@ unsigned long uprobe_get_swbp_addr(struc
static struct undef_hook uprobes_arm_break_hook = {
.instr_mask = 0x0fffffff,
.instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff),
- .cpsr_mask = MODE_MASK,
+ .cpsr_mask = (PSR_T_BIT | MODE_MASK),
.cpsr_val = USR_MODE,
.fn = uprobe_trap_handler,
};
@@ -212,7 +212,7 @@ static struct undef_hook uprobes_arm_bre
static struct undef_hook uprobes_arm_ss_hook = {
.instr_mask = 0x0fffffff,
.instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff),
- .cpsr_mask = MODE_MASK,
+ .cpsr_mask = (PSR_T_BIT | MODE_MASK),
.cpsr_val = USR_MODE,
.fn = uprobe_trap_handler,
};
Patches currently in stable-queue which might be from fredrik@xxxxxxxxxx are
queue-5.10/arm-9071-1-uprobes-don-t-hook-on-thumb-instructions.patch
