From: Ian Rogers Date: Tue, 9 Mar 2021 23:49:45 +0000 (-0800) Subject: perf synthetic events: Avoid write of uninitialized memory when generating PERF_RECOR... X-Git-Tag: v5.11.11~23 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3c840c4de8a9e733231316b8de9a6f8a8a5eeb25;p=thirdparty%2Fkernel%2Fstable.git perf synthetic events: Avoid write of uninitialized memory when generating PERF_RECORD_MMAP* records [ Upstream commit 2a76f6de07906f0bb5f2a13fb02845db1695cc29 ] 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 Signed-off-by: Sasha Levin --- diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index 2947e3f3c6d9d..dda0a6a3173d3 100644 --- a/tools/perf/util/synthetic-events.c +++ b/tools/perf/util/synthetic-events.c @@ -384,7 +384,7 @@ 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'; @@ -444,11 +444,12 @@ 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;