Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Fri, 20 Jan 2023 10:58:28 -0800 | Subject | [PATCH v2] perf buildid: Avoid copy of uninitialized memory | From | Ian Rogers <> |
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build_id__init only copies the buildid data up to size leaving the rest of the data array uninitialized. Copying the full array during synthesis means the written event contains uninitialized memory. Ensure the size is less that the buffer size and only copy the bytes that were initialized. This was detected by the Clang/LLVM memory sanitizer.
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ian Rogers <irogers@google.com>
v2. Avoids the potential for copying too much as suggested by Arnaldo. --- tools/perf/util/synthetic-events.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index 3ab6a92b1a6d..9ab9308ee80c 100644 --- a/tools/perf/util/synthetic-events.c +++ b/tools/perf/util/synthetic-events.c @@ -2219,8 +2219,8 @@ int perf_event__synthesize_build_id(struct perf_tool *tool, struct dso *pos, u16 len = pos->long_name_len + 1; len = PERF_ALIGN(len, NAME_ALIGN); - memcpy(&ev.build_id.build_id, pos->bid.data, sizeof(pos->bid.data)); - ev.build_id.size = pos->bid.size; + ev.build_id.size = min(pos->bid.size, sizeof(pos->bid.data)); + memcpy(&ev.build_id.build_id, pos->bid.data, ev.build_id.size); ev.build_id.header.type = PERF_RECORD_HEADER_BUILD_ID; ev.build_id.header.misc = misc | PERF_RECORD_MISC_BUILD_ID_SIZE; ev.build_id.pid = machine->pid; -- 2.39.0.246.g2a6d74b583-goog
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