From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10ED845BD4E; Tue, 21 Jul 2026 18:08:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657313; cv=none; b=scvpQgRgo7H01ztmXo8wJRcH6WRiZgIHLIgMLHarGeDtrv2SmKI4L1LpEOeNkKXHSih/KwaqKT+WB34W8SZii1n0ZfgRHIxHhwFUSYVsQWsQ3Ee4m2BkW1yx5nw73eFZ49ph1w6hzUe6krTU0wne4A+3dZdOxgWmWgBFJUMIYPY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657313; c=relaxed/simple; bh=Rs9IYlZ38XnukBh8zt/gicOZ3hpcHK39DPvL753YF/E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=fGDwwwDidXgC3SoCZaCK/9V+JRfN8kRw8yMOopHkVoO8jDlrY7quxe2ckE5lRthOF57ZVDfcaylFbSn/WVocygEvv+us76Xnsh5Q3fhvZD0vOTZYx4YYw81IE2TQfe7ELTFZ2vDj6qW60WLsg2FB38C70uR/I/cO3S5fDsB5ZIw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rJ04ehjL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="rJ04ehjL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77D241F000E9; Tue, 21 Jul 2026 18:08:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784657312; bh=sWflF0DasTEOMk8XqdliOSjRjDB/TtDu6gIJaTkuH1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=rJ04ehjLHtc9wqj8TFgNDLzKB/w1+7KPPWqRiIv0X6wakvVQwX9Ww1Dp/AZyBwxHU +O3wI9we+08OzwseEeDOn0uIIMjUlGXYGW830Qs0JY9AT6UVxQRPiMt7Bc/AdWa9wq ICZcv+r1JwdfZV4gHZOYP+Vz6PRax+MOCp1vK0Ng= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, sashiko-bot , Namhyung Kim , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH 6.18 0717/1611] perf symbols: Bounds-check descsz in sysfs__read_build_id() GNU fallback Date: Tue, 21 Jul 2026 17:13:53 +0200 Message-ID: <20260721152531.508275188@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnaldo Carvalho de Melo [ Upstream commit 1b4e9fbdeabc549965e70ac0cd8095d57ff6df06 ] When sysfs__read_build_id() matches NT_GNU_BUILD_ID with the right namesz but the name content is not "GNU", it falls back to reading descsz bytes into the stack buffer bf[BUFSIZ]: } else if (read(fd, bf, descsz) != (ssize_t)descsz) Unlike the else branch which validates namesz + descsz against sizeof(bf), this path passes descsz directly to read() without any bounds check. A crafted sysfs file with a large n_descsz overflows the 8192-byte stack buffer. Add a descsz > sizeof(bf) check before the read, breaking out of the loop on oversized values. Fixes: e5a1845fc0aeca85 ("perf symbols: Split out util/symbol-elf.c") Reported-by: sashiko-bot Cc: Namhyung Kim Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/util/symbol-elf.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 2b91255123c340..f96aec292ade23 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -959,8 +959,13 @@ int sysfs__read_build_id(const char *filename, struct build_id *bid) err = 0; break; } - } else if (read(fd, bf, descsz) != (ssize_t)descsz) - break; + } else { + /* descsz from untrusted file — clamp to buffer */ + if (descsz > sizeof(bf)) + break; + if (read(fd, bf, descsz) != (ssize_t)descsz) + break; + } } else { size_t n; -- 2.53.0