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| author | Jon Medhurst <tixy@yxit.co.uk> | 2011-04-19 10:52:16 +0100 |
|---|---|---|
| committer | Nicolas Pitre <nicolas.pitre@linaro.org> | 2011-04-28 23:40:59 -0400 |
| commit | f704a6e25bd07e1381af81f19fb1d123975807b1 (patch) | |
| tree | dc571d149ae5a78c9adf667cf512438615470ebe /arch/arm | |
| parent | 72c2bab2be734d63dee4342e67b1754c54fded70 (diff) | |
| download | lwn-f704a6e25bd07e1381af81f19fb1d123975807b1.tar.gz lwn-f704a6e25bd07e1381af81f19fb1d123975807b1.zip | |
ARM: kprobes: Reject probing of undefined data processing instructions
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>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/kernel/kprobes-decode.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c index dc315c12d5f3..4715537b490c 100644 --- a/arch/arm/kernel/kprobes-decode.c +++ b/arch/arm/kernel/kprobes-decode.c @@ -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 */ |