Messages in this thread | | | Date | Wed, 10 Mar 2021 12:48:36 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH] perf synthetic events: Avoid write of uninitialized memory. |
| |
On Tue, Mar 09, 2021 at 03:49:45PM -0800, Ian Rogers wrote: > Account for alignment bytes in the zero-ing memset. > > Signed-off-by: Ian Rogers <irogers@google.com> > --- > tools/perf/util/synthetic-events.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c > index b698046ec2db..31bf3dd6a1e0 100644 > --- a/tools/perf/util/synthetic-events.c > +++ b/tools/perf/util/synthetic-events.c > @@ -424,7 +424,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, > > while (!io.eof) { > static const char anonstr[] = "//anon"; > - size_t size; > + size_t size, aligned_size; > > /* ensure null termination since stack will be reused. */ > event->mmap2.filename[0] = '\0'; > @@ -484,11 +484,12 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, > } > > size = strlen(event->mmap2.filename) + 1; > - size = PERF_ALIGN(size, sizeof(u64)); > + aligned_size = PERF_ALIGN(size, sizeof(u64)); > event->mmap2.len -= event->mmap.start; > event->mmap2.header.size = (sizeof(event->mmap2) - > - (sizeof(event->mmap2.filename) - size)); > - memset(event->mmap2.filename + size, 0, machine->id_hdr_size); > + (sizeof(event->mmap2.filename) - aligned_size)); > + memset(event->mmap2.filename + size, 0, machine->id_hdr_size + > + (aligned_size - size));
so we did not zero the extra alignment bytes, nice ;-) looks good
Acked-by: Jiri Olsa <jolsa@redhat.com>
thanks, jirka
> event->mmap2.header.size += machine->id_hdr_size; > event->mmap2.pid = tgid; > event->mmap2.tid = pid; > -- > 2.30.1.766.gb4fecdf3b7-goog >
| |