On Tue, 24 Nov 2020 11:19:43 +0100 Borislav Petkov <[email protected]> wrote:
> From: Borislav Petkov <[email protected]> > > Simplify code, no functional changes. You've made a functional change. Improve decoding error check :) Anyway, this looks good to me. Acked-by: Masami Hiramatsu <[email protected]> Thank you! > > Signed-off-by: Borislav Petkov <[email protected]> > --- > arch/x86/kernel/kprobes/core.c | 17 +++++++++++------ > arch/x86/kernel/kprobes/opt.c | 9 +++++++-- > 2 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > index 547c7abb39f5..43d4a3056d21 100644 > --- a/arch/x86/kernel/kprobes/core.c > +++ b/arch/x86/kernel/kprobes/core.c > @@ -285,6 +285,8 @@ static int can_probe(unsigned long paddr) > /* Decode instructions */ > addr = paddr - offset; > while (addr < paddr) { > + int ret; > + > /* > * Check if the instruction has been modified by another > * kprobe, in which case we replace the breakpoint by the > @@ -296,8 +298,10 @@ static int can_probe(unsigned long paddr) > __addr = recover_probed_instruction(buf, addr); > if (!__addr) > return 0; > - kernel_insn_init(&insn, (void *)__addr, MAX_INSN_SIZE); > - insn_get_length(&insn); > + > + ret = insn_decode(&insn, (void *)__addr, MAX_INSN_SIZE, > INSN_MODE_KERN); > + if (ret < 0) > + return 0; > > /* > * Another debugging subsystem might insert this breakpoint. > @@ -340,8 +344,8 @@ static int is_IF_modifier(kprobe_opcode_t *insn) > int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn) > { > kprobe_opcode_t buf[MAX_INSN_SIZE]; > - unsigned long recovered_insn = > - recover_probed_instruction(buf, (unsigned long)src); > + unsigned long recovered_insn = recover_probed_instruction(buf, > (unsigned long)src); > + int ret; > > if (!recovered_insn || !insn) > return 0; > @@ -351,8 +355,9 @@ int __copy_instruction(u8 *dest, u8 *src, u8 *real, > struct insn *insn) > MAX_INSN_SIZE)) > return 0; > > - kernel_insn_init(insn, dest, MAX_INSN_SIZE); > - insn_get_length(insn); > + ret = insn_decode(insn, dest, MAX_INSN_SIZE, INSN_MODE_KERN); > + if (ret < 0) > + return 0; > > /* We can not probe force emulate prefixed instruction */ > if (insn_has_emulate_prefix(insn)) > diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c > index 041f0b50bc27..4d67571249e1 100644 > --- a/arch/x86/kernel/kprobes/opt.c > +++ b/arch/x86/kernel/kprobes/opt.c > @@ -299,6 +299,8 @@ static int can_optimize(unsigned long paddr) > addr = paddr - offset; > while (addr < paddr - offset + size) { /* Decode until function end */ > unsigned long recovered_insn; > + int ret; > + > if (search_exception_tables(addr)) > /* > * Since some fixup code will jumps into this function, > @@ -308,8 +310,11 @@ static int can_optimize(unsigned long paddr) > recovered_insn = recover_probed_instruction(buf, addr); > if (!recovered_insn) > return 0; > - kernel_insn_init(&insn, (void *)recovered_insn, MAX_INSN_SIZE); > - insn_get_length(&insn); > + > + ret = insn_decode(&insn, (void *)recovered_insn, MAX_INSN_SIZE, > INSN_MODE_KERN); > + if (ret < 0) > + return 0; > + > /* Another subsystem puts a breakpoint */ > if (insn.opcode.bytes[0] == INT3_INSN_OPCODE) > return 0; > -- > 2.21.0 > -- Masami Hiramatsu <[email protected]>
