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ARM: kprobes: Reject probing of undefined data processing instructions

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The instruction decoding in space_cccc_000x needs to reject probing of
instructions with undefined patterns as they may in future become
defined and then emulated faultily - as has already happened with the
SMC instruction.

This fix is achieved by testing for the instruction patterns we want to
probe and making the the default fall-through paths reject probes. This
also allows us to remove some explicit tests for instructions that we
wish to reject, as that is now the default action.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
This commit is contained in:
Jon Medhurst 2011-04-19 10:52:16 +01:00 committed by Nicolas Pitre
parent 72c2bab2be
commit f704a6e25b
1 changed files with 17 additions and 14 deletions
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31
arch/arm/kernel/kprobes-decode.c
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@ -966,14 +966,6 @@ space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
/* cccc 0001 0xx0 xxxx xxxx xxxx xxxx xxx0 xxxx */
if ((insn & 0x0f900010) == 0x01000000) {
/* BXJ : cccc 0001 0010 xxxx xxxx xxxx 0010 xxxx */
/* MSR : cccc 0001 0x10 xxxx xxxx xxxx 0000 xxxx */
/* MRS spsr : cccc 0001 0100 xxxx xxxx xxxx 0000 xxxx */
if ((insn & 0x0ff000f0) == 0x01200020 ||
(insn & 0x0fb000f0) == 0x01200000 ||
(insn & 0x0ff000f0) == 0x01400000)
return INSN_REJECTED;
/* MRS cpsr : cccc 0001 0000 xxxx xxxx xxxx 0000 xxxx */
if ((insn & 0x0ff000f0) == 0x01000000) {
if (is_r15(insn, 12))
@ -994,17 +986,21 @@ space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
/* SMLAxy : cccc 0001 0000 xxxx xxxx xxxx 1xx0 xxxx : Q */
/* SMLAWy : cccc 0001 0010 xxxx xxxx xxxx 1x00 xxxx : Q */
return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
if ((insn & 0x0ff00090) == 0x01000080 ||
(insn & 0x0ff000b0) == 0x01200080)
return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi);
/* BXJ : cccc 0001 0010 xxxx xxxx xxxx 0010 xxxx */
/* MSR : cccc 0001 0x10 xxxx xxxx xxxx 0000 xxxx */
/* MRS spsr : cccc 0001 0100 xxxx xxxx xxxx 0000 xxxx */
/* Other instruction encodings aren't yet defined */
return INSN_REJECTED;
}
/* cccc 0001 0xx0 xxxx xxxx xxxx xxxx 0xx1 xxxx */
else if ((insn & 0x0f900090) == 0x01000010) {
/* BKPT : 1110 0001 0010 xxxx xxxx xxxx 0111 xxxx */
if ((insn & 0xfff000f0) == 0xe1200070)
return INSN_REJECTED;
/* BLX(2) : cccc 0001 0010 xxxx xxxx xxxx 0011 xxxx */
/* BX : cccc 0001 0010 xxxx xxxx xxxx 0001 xxxx */
if ((insn & 0x0ff000d0) == 0x01200010) {
@ -1022,7 +1018,14 @@ space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
/* QSUB : cccc 0001 0010 xxxx xxxx xxxx 0101 xxxx :Q */
/* QDADD : cccc 0001 0100 xxxx xxxx xxxx 0101 xxxx :Q */
/* QDSUB : cccc 0001 0110 xxxx xxxx xxxx 0101 xxxx :Q */
return prep_emulate_rd12rn16rm0_wflags(insn, asi);
if ((insn & 0x0f9000f0) == 0x01000050)
return prep_emulate_rd12rn16rm0_wflags(insn, asi);
/* BKPT : 1110 0001 0010 xxxx xxxx xxxx 0111 xxxx */
/* SMC : cccc 0001 0110 xxxx xxxx xxxx 0111 xxxx */
/* Other instruction encodings aren't yet defined */
return INSN_REJECTED;
}
/* cccc 0000 xxxx xxxx xxxx xxxx xxxx 1001 xxxx */