Em Fri, Dec 10, 2021 at 02:47:49PM +0530, kajoljain escreveu:
>
>
> On 12/1/21 6:03 PM, German Gomez wrote:
> > The size of the cache of register values is arch-dependant
> > (PERF_REGS_MAX). This has the potential of causing an out-of-bounds
> > access in the function "perf_reg_value" if the local architecture
> > contains less registers than the one the perf.data file was recorded on.
> >
> > Since the maximum number of registers is bound by the bitmask "u64
> > cache_mask", and the size of the cache when running under x86 systems is
> > 64 already, fix the size to 64 and add a range-check to the function
> > "perf_reg_value" to prevent out-of-bounds access.
> >
>
> Patch looks good to me.
>
> Reviewed-by: Kajol Jain<kjain@xxxxxxxxxxxxx>
Thanks, applied.
- Arnaldo
> Thanks,
> Kajol Jain
>
> > Signed-off-by: German Gomez <german.gomez@xxxxxxx>
> > ---
> > tools/perf/util/event.h | 5 ++++-
> > tools/perf/util/perf_regs.c | 3 +++
> > 2 files changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
> > index 95ffed663..c59331eea 100644
> > --- a/tools/perf/util/event.h
> > +++ b/tools/perf/util/event.h
> > @@ -44,13 +44,16 @@ struct perf_event_attr;
> > /* perf sample has 16 bits size limit */
> > #define PERF_SAMPLE_MAX_SIZE (1 << 16)
> >
> > +/* number of register is bound by the number of bits in regs_dump::mask (64) */
> > +#define PERF_SAMPLE_REGS_CACHE_SIZE (8 * sizeof(u64))
> > +
> > struct regs_dump {
> > u64 abi;
> > u64 mask;
> > u64 *regs;
> >
> > /* Cached values/mask filled by first register access. */
> > - u64 cache_regs[PERF_REGS_MAX];
> > + u64 cache_regs[PERF_SAMPLE_REGS_CACHE_SIZE];
> > u64 cache_mask;
> > };
> >
> > diff --git a/tools/perf/util/perf_regs.c b/tools/perf/util/perf_regs.c
> > index 5ee47ae15..06a7461ba 100644
> > --- a/tools/perf/util/perf_regs.c
> > +++ b/tools/perf/util/perf_regs.c
> > @@ -25,6 +25,9 @@ int perf_reg_value(u64 *valp, struct regs_dump *regs, int id)
> > int i, idx = 0;
> > u64 mask = regs->mask;
> >
> > + if ((u64)id >= PERF_SAMPLE_REGS_CACHE_SIZE)
> > + return -EINVAL;
> > +
> > if (regs->cache_mask & (1ULL << id))
> > goto out;
> >
> >
--
- Arnaldo
