From: Borislav Petkov <b...@suse.de> Hi,
here's what I had in mind, finally split into proper patches. The final goal is for all users of the decoder to simply call insn_decode() and look at its retval. Simple. As to amluto's question about detecting partial insns, see the diff below. Running that gives: insn buffer: 0x48 0xcf 0x48 0x83 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 supplied buf size: 15, ret 0 supplied buf size: 2, ret 0 supplied buf size: 3, ret 0 supplied buf size: 4, ret 0 and the return value is always success. Which means that that buf_len that gets supplied to the decoder functions doesn't really work and I need to look into it. That is, provided this is how we want to control what the instruction decoder decodes - by supplying the length of the buffer it should look at. We could also say that probably there should be a way to say "decode only the first insn in the buffer and ignore the rest". That is all up to the use cases so I'm looking for suggestions here. In any case, at least the case where I give it 0x48 0xcf 0x48 0x83 and say that buf size is 4, should return an error because the second insn is incomplete. So I need to go look at that now. Thx. --- diff --git a/arch/x86/tools/insn_sanity.c b/arch/x86/tools/insn_sanity.c index 51309df285b4..41e1ae0cd833 100644 --- a/arch/x86/tools/insn_sanity.c +++ b/arch/x86/tools/insn_sanity.c @@ -220,6 +220,45 @@ static void parse_args(int argc, char **argv) } } +static void run_insn_limits_test(void) +{ + unsigned char b[MAX_INSN_SIZE]; + struct insn insn; + int ret, i, size; + + memset(b, INSN_NOP, MAX_INSN_SIZE); + + /* IRETQ */ + b[0] = 0x48; + b[1] = 0xcf; + + /* partial add $0x8, %rsp */ + b[2] = 0x48; + b[3] = 0x83; + + printf("insn buffer:\n"); + + for (i = 0; i < MAX_INSN_SIZE; i++) + printf("0x%hhx ", b[i]); + printf("\n"); + + size = MAX_INSN_SIZE; + ret = insn_decode(&insn, b, size, INSN_MODE_64); + printf("supplied buf size: %d, ret %d\n", size, ret); + + size = 2; + ret = insn_decode(&insn, b, size, INSN_MODE_64); + printf("supplied buf size: %d, ret %d\n", size, ret); + + size = 3; + ret = insn_decode(&insn, b, size, INSN_MODE_64); + printf("supplied buf size: %d, ret %d\n", size, ret); + + size = 4; + ret = insn_decode(&insn, b, size, INSN_MODE_64); + printf("supplied buf size: %d, ret %d\n", size, ret); +} + int main(int argc, char **argv) { int insns = 0, ret; @@ -265,5 +304,7 @@ int main(int argc, char **argv) errors, seed); + run_insn_limits_test(); + return errors ? 1 : 0; } Borislav Petkov (19): x86/insn: Rename insn_decode() to insn_decode_regs() x86/insn: Add @buf_len param to insn_init() kernel-doc comment x86/insn: Add an insn_decode() API x86/insn-eval: Handle return values from the decoder x86/boot/compressed/sev-es: Convert to insn_decode() perf/x86/intel/ds: Check insn_get_length() retval perf/x86/intel/ds: Check return values of insn decoder functions x86/alternative: Use insn_decode() x86/mce: Convert to insn_decode() x86/kprobes: Convert to insn_decode() x86/sev-es: Convert to insn_decode() x86/traps: Convert to insn_decode() x86/uprobes: Convert to insn_decode() x86/tools/insn_decoder_test: Convert to insn_decode() tools/objtool: Convert to insn_decode() x86/tools/insn_sanity: Convert to insn_decode() tools/perf: Convert to insn_decode() x86/insn: Remove kernel_insn_init() x86/insn: Make insn_complete() static arch/x86/boot/compressed/sev-es.c | 11 +- arch/x86/events/intel/ds.c | 4 +- arch/x86/events/intel/lbr.c | 10 +- arch/x86/include/asm/insn-eval.h | 4 +- arch/x86/include/asm/insn.h | 42 ++-- arch/x86/kernel/alternative.c | 6 +- arch/x86/kernel/cpu/mce/severity.c | 12 +- arch/x86/kernel/kprobes/core.c | 17 +- arch/x86/kernel/kprobes/opt.c | 9 +- arch/x86/kernel/sev-es.c | 15 +- arch/x86/kernel/traps.c | 7 +- arch/x86/kernel/umip.c | 2 +- arch/x86/kernel/uprobes.c | 8 +- arch/x86/lib/insn-eval.c | 20 +- arch/x86/lib/insn.c | 190 ++++++++++++++---- arch/x86/tools/insn_decoder_test.c | 10 +- arch/x86/tools/insn_sanity.c | 8 +- tools/arch/x86/include/asm/insn.h | 42 ++-- tools/arch/x86/lib/insn.c | 190 ++++++++++++++---- tools/include/linux/kconfig.h | 73 +++++++ tools/objtool/arch/x86/decode.c | 9 +- tools/perf/arch/x86/tests/insn-x86.c | 9 +- tools/perf/arch/x86/util/archinsn.c | 9 +- .../intel-pt-decoder/intel-pt-insn-decoder.c | 17 +- 24 files changed, 507 insertions(+), 217 deletions(-) create mode 100644 tools/include/linux/kconfig.h -- 2.21.0