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Thu, 02 Apr 2026 09:04:37 -0700 (PDT) Received: from fedora ([61.74.238.173]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82cfebe5b23sm2822987b3a.59.2026.04.02.09.04.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Apr 2026 09:04:37 -0700 (PDT) From: SeungJu Cheon To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org Cc: mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, me@brighamcampbell.com, shuah@kernel.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linux.dev, SeungJu Cheon Subject: [PATCH v3] perf header: Validate build_id filename length to prevent buffer overflow Date: Fri, 3 Apr 2026 01:04:10 +0900 Message-ID: <20260402160410.425978-1-suunj1331@gmail.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel-mentees@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The build_id parsing functions calculate a filename length from the event header size and read directly into a stack buffer of PATH_MAX bytes without bounds checking. A malformed perf.data file with a crafted header.size can cause the length to be negative or exceed PATH_MAX, resulting in a stack buffer overflow. Add bounds checking for the filename length in both perf_header__read_build_ids() and the ABI quirk variant. Print a warning message when invalid length is detected. Signed-off-by: SeungJu Cheon --- v3: - Fix printf format specifier: %d -> %zd for ssize_t (Sashiko) v2: - Add warning message when invalid filename length detected --- tools/perf/util/header.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 9142a8ba4019..9ffc0f4ca6d1 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -2545,6 +2545,11 @@ static int perf_header__read_build_ids_abi_quirk(struct perf_header *header, perf_event_header__bswap(&old_bev.header); len = old_bev.header.size - sizeof(old_bev); + if (len < 0 || len >= PATH_MAX) { + pr_warning("invalid build_id filename length %zd\n", len); + return -1; + } + if (readn(input, filename, len) != len) return -1; @@ -2587,6 +2592,11 @@ static int perf_header__read_build_ids(struct perf_header *header, perf_event_header__bswap(&bev.header); len = bev.header.size - sizeof(bev); + if (len < 0 || len >= PATH_MAX) { + pr_warning("invalid build_id filename length %zd\n", len); + goto out; + } + if (readn(input, filename, len) != len) goto out; /* -- 2.52.0