From 2a76f6de07906f0bb5f2a13fb02845db1695cc29 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Tue, 9 Mar 2021 15:49:45 -0800 Subject: perf synthetic events: Avoid write of uninitialized memory when generating PERF_RECORD_MMAP* records Account for alignment bytes in the zero-ing memset. Fixes: 1a853e36871b533c ("perf record: Allow specifying a pid to record") Signed-off-by: Ian Rogers Acked-by: Jiri Olsa Cc: Ingo Molnar Cc: Alexander Shishkin Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lore.kernel.org/lkml/20210309234945.419254-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/synthetic-events.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'tools/perf/util') diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index 5dd451695f33..dff178103ce5 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 @@ out: } 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)); event->mmap2.header.size += machine->id_hdr_size; event->mmap2.pid = tgid; event->mmap2.tid = pid; -- cgit v1.2.3