* Ian Rogers <irog...@google.com> wrote:
> From: Numfor Mbiziwo-Tiapo <n...@google.com> > > If insn_init is given a NULL kaddr and 0 buflen then validate_next will > perform arithmetic on NULL, add a guard to avoid this. > > Don't perform unaligned loads in __get_next and __peek_nbyte_next as > these are forms of undefined behavior. So, 'insn' is a kernel structure, usually allocated on the kernel stack. How could these fields ever be unaligned? > > These problems were identified using the undefined behavior sanitizer > (ubsan) with the tools version of the code and perf test. Part of this > patch was previously posted here: > https://lore.kernel.org/lkml/20190724184512.162887-4-n...@google.com/ > > Signed-off-by: Ian Rogers <irog...@google.com> > Signed-off-by: Numfor Mbiziwo-Tiapo <n...@google.com> > --- > arch/x86/lib/insn.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c > index 404279563891..57236940de46 100644 > --- a/arch/x86/lib/insn.c > +++ b/arch/x86/lib/insn.c > @@ -17,13 +17,13 @@ > > /* Verify next sizeof(t) bytes can be on the same instruction */ > #define validate_next(t, insn, n) \ > - ((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr) > + ((insn)->end_kaddr != 0 && (insn)->next_byte + sizeof(t) + n <= > (insn)->end_kaddr) > > #define __get_next(t, insn) \ > - ({ t r = *(t*)insn->next_byte; insn->next_byte += sizeof(t); r; }) > + ({ t r; memcpy(&r, insn->next_byte, sizeof(t)); insn->next_byte += > sizeof(t); r; }) > > #define __peek_nbyte_next(t, insn, n) \ > - ({ t r = *(t*)((insn)->next_byte + n); r; }) > + ({ t r; memcpy(&r, (insn)->next_byte + n, sizeof(t)); r; }) > > #define get_next(t, insn) \ > ({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; > __get_next(t, insn); }) Is there any code generation side effect of this change to the resulting code? Thanks, Ingo
