From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f71.google.com (mail-pj1-f71.google.com [209.85.216.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 03F2846C4AE for ; Tue, 15 Sep 2026 08:20:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789460477; cv=none; b=L9Eh4wJ7pcPM/FGqHRu4Y9TdtpwhoZ0+EKombSg366xRsxxo6S5jL1TNz0jt6S5nJ7AJwDoZtGnRgIntTGnHq1H3Q0MeLiH2J6UlWFjsrh/9skVl52jSGouFWbv93Wxs6YnAlQCeBR4h4MFPSolNw1LNjVgwUCYPgSOP82dbl1U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789460477; c=relaxed/simple; bh=OaAwr1sBjpntRvDMR8Yr1mj2+C2DlJcpETypf5U3EWo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=O26SSSJ3pumRdCs4KiWI1MNxCTma/0sG3dljzdGGpo2LDN7WXrH0SFp9t1ZJHnV0PvOrWnBRyRet6yY7u2MRkPz4MIY5yuiDY/P/jPMFiZ39Fcn6E6Q8eJnuNke667ddOLKOtl1de1dX2NnqC6vTLB1jOTat0VJXo6tX1fysqaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--morbo.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=sO9jykEa; arc=none smtp.client-ip=209.85.216.71 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--morbo.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="sO9jykEa" Received: by mail-pj1-f71.google.com with SMTP id 98e67ed59e1d1-38dbf293831so9420541a91.3 for ; Tue, 15 Sep 2026 01:20:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1789460399; x=1790065199; darn=lists.linux.dev; h=content-transfer-encoding:content-type:cc:to:from:subject :message-id:references:mime-version:in-reply-to:date:from:to:cc :subject:date:message-id:reply-to:content-type; bh=ANECGYJQk2+Ya+FPrAm+IsCBeyM6Er0meffRIzFfkVU=; b=sO9jykEaDb+3nNG78ZyxtEsps7iLY10x4V+iey+hfFjYWmhgI0w9ozgFuhfAPx8Rpa 43GhHcXtyprZgMVoB2ybJnIS25FU8WZwGve9R24alVRTyYKW+aWSxnnChb52q8Jd0A1Y aALvCu0XupY9jSWWeiHehjRs8UJm0seBRmQ0hUSjy2SrXoCHDMM89oxS3knFlRGwOnjp ekBbd7GI71VpKf7FCoOVFFKuZ13QTfEUe1tI0a6Jl2gTX7FQ4sQijmzOv6t6j0QSymWs Pldj+SttyY6iEqraNglnvuRzt7BPgSMoHVXZ33gKgR11A1npIPjYbBAsUd2tEKW45h1I 7hng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789460399; x=1790065199; h=content-transfer-encoding:content-type:cc:to:from:subject :message-id:references:mime-version:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=ANECGYJQk2+Ya+FPrAm+IsCBeyM6Er0meffRIzFfkVU=; b=Ga+g2NtDFXLuvTDHi+YpJLsrFEy9eTfo70fmE/oWFE9rD5Ylr9fF22dKIg4cU/tPFH F3EhwIk7FCVxMfMe2ojF+3d5HFO4l1e1N2TYlZ5bTCZRv7yn+Y515D3eXxytIyZyP7ES ezKT+1Xr9rRo3J81ZN3cQ0ieZxp2ftH46rbBp/EvZSNB0KkV/8I0ldZtcbY9OZpDPVuJ ypMPzn8I324235ivlBCInGtdRLMoicleOTx8CS90n1I/MB//4xJsEGvTm6kFqnlIMgEU GhEY5O9e2zAArKsZQMZoEHDvncetY/hwnFEO9nUlzIPI65cwZQRD7OAY7pI9S3FGcb1L O2bg== X-Forwarded-Encrypted: i=1; AKwUvBzOXCPEQe2un5PsCP/XVZS5X0Cr0XwKy1KHJkkOF6Gk8lZAklogPghg+ZCvy0F+ER+08hvAHF1GAZg=@lists.linux.dev X-Gm-Message-State: AFuF++kJAxhUOsVFiy2mW30k3XB7lyxtyyTnb6Jl0k/isRaTMrI17jm0 ZSGCxHcJTbQO1keYRCxF5b/4PU4r3SL5zQHQnkV1EZ3pJlSE+ribYMApfZmLjJdWwWthYdZ3Th8 L X-Received: from pllj10.prod.google.com ([2002:a17:902:758a:b0:2dd:63c:daa3]) (user=morbo job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:ccd1:b0:2dd:40cb:a04c with SMTP id d9443c01a7336-2dd8386925cmr476775ad.19.1789460398847; Tue, 15 Sep 2026 01:19:58 -0700 (PDT) Date: Tue, 15 Sep 2026 08:18:29 +0000 In-Reply-To: <20260915081910.4142719-1-morbo@google.com> Precedence: bulk X-Mailing-List: loongarch@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260915081910.4142719-1-morbo@google.com> X-Mailer: git-send-email 2.55.0.1032.g73a4cd73de-goog Message-ID: <20260915081910.4142719-13-morbo@google.com> Subject: [PATCH 12/28] fortify: Convert strlcat() to snprintf() in strcat() From: Bill Wendling To: linux-kernel@vger.kernel.org Cc: Bill Wendling , codemender-patching+linux@google.com, Russell King , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , "James E.J. Bottomley" , Helge Deller , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Ian Abbott , H Hartley Sweeten , Tony Luck , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Matthew Brost , "=?UTF-8?q?Thomas=20Hellstr=C3=B6m?=" , Rodrigo Vivi , Dmitry Torokhov , Matthias Schwarzott , Mauro Carvalho Chehab , Tony Nguyen , Przemek Kitszel , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Arend van Spriel , Rob Herring , Saravana Kannan , Krzysztof Kozlowski , Sylwester Nawrocki , Peter Griffin , Alim Akhtar , Linus Walleij , Anil Gurumurthy , Sudarsana Kalluru , "Martin K. Petersen" , Trond Myklebust , Anna Schumaker , Mike Marshall , Martin Brandenburg , Kees Cook , Jiri Pirko , Simon Horman , Chuck Lever , Jeff Layton , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Jaroslav Kysela , Takashi Iwai , Andrew Morton , "Mike Rapoport (Microsoft)" , Kanglong Wang , Tiezhu Yang , Qiang Ma , Randy Dunlap , Pengpeng Hou , Ard Biesheuvel , Breno Leitao , Thorsten Blum , Harshit Mogalapalli , Greg Kroah-Hartman , Lyude Paul , Ashutosh Desai , Imre Deak , Dmitry Baryshkov , Johan Hovold , Johannes Berg , Miri Korenblit , Alexander Stein , Cryolitia PukNgae , Jiaming Zhang , Will Porter , Cen Zhang , "=?UTF-8?q?C=C3=A1ssio=20Gabriel?=" , Rong Zhang , Arun Raghavan , linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-edac@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-input@vger.kernel.org, linux-media@vger.kernel.org, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, brcm80211@lists.linux.dev, brcm80211-dev-list.pdl@broadcom.com, devicetree@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-gpio@vger.kernel.org, linux-scsi@vger.kernel.org, linux-nfs@vger.kernel.org, devel@lists.orangefs.org, linux-hardening@vger.kernel.org, linux-sound@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable The fortified implementation of strcat() in include/linux/fortify-string.h currently relies on strlcat() to perform bounded concatenation and detect buffer overflows. In preparation for removing the deprecated strlcat() API[1], replace the strlcat() call in strcat(). When the destination buffer size is unknown (SIZE_MAX), call __underlying_strcat() directly. Otherwise, determine the destination length with __fortify_strlen() and append the source string using __builtin_snprintf(), preserving the existing fortify_panic() check on overflow. Link: https://github.com/KSPP/linux/issues/370 [1] Cc: codemender-patching+linux@google.com Assisted-by: SecurityEngineer:Gemini1.5Pro [editor_update_file, shell_comma= nd_run, test_runner_run_kunit_test] Signed-off-by: Bill Wendling --- Cc: Russell King Cc: Huacai Chen Cc: WANG Xuerui Cc: Thomas Bogendoerfer Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: x86@kernel.org Cc: "H. Peter Anvin" Cc: Ian Abbott Cc: H Hartley Sweeten Cc: Tony Luck Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Simona Vetter Cc: Matthew Brost Cc: "Thomas Hellstr=C3=B6m" Cc: Rodrigo Vivi Cc: Dmitry Torokhov Cc: Matthias Schwarzott Cc: Mauro Carvalho Chehab Cc: Tony Nguyen Cc: Przemek Kitszel Cc: Andrew Lunn Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Arend van Spriel Cc: Rob Herring Cc: Saravana Kannan Cc: Krzysztof Kozlowski Cc: Sylwester Nawrocki Cc: Peter Griffin Cc: Alim Akhtar Cc: Linus Walleij Cc: Anil Gurumurthy Cc: Sudarsana Kalluru Cc: "Martin K. Petersen" Cc: Trond Myklebust Cc: Anna Schumaker Cc: Mike Marshall Cc: Martin Brandenburg Cc: Kees Cook Cc: Jiri Pirko Cc: Simon Horman Cc: Chuck Lever Cc: Jeff Layton Cc: NeilBrown Cc: Olga Kornievskaia Cc: Dai Ngo Cc: Tom Talpey Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Bill Wendling Cc: Andrew Morton Cc: "Mike Rapoport (Microsoft)" Cc: Kanglong Wang Cc: Tiezhu Yang Cc: Qiang Ma Cc: Randy Dunlap Cc: Pengpeng Hou Cc: Ard Biesheuvel Cc: Breno Leitao Cc: Thorsten Blum Cc: Harshit Mogalapalli Cc: Greg Kroah-Hartman Cc: Lyude Paul Cc: Ashutosh Desai Cc: Imre Deak Cc: Dmitry Baryshkov Cc: Johan Hovold Cc: Johannes Berg Cc: Miri Korenblit Cc: Alexander Stein Cc: Cryolitia PukNgae Cc: Jiaming Zhang Cc: Will Porter Cc: Cen Zhang Cc: "C=C3=A1ssio Gabriel" Cc: Rong Zhang Cc: Arun Raghavan Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: loongarch@lists.linux.dev Cc: linux-mips@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linux-edac@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: intel-xe@lists.freedesktop.org Cc: linux-input@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: intel-wired-lan@lists.osuosl.org Cc: netdev@vger.kernel.org Cc: linux-wireless@vger.kernel.org Cc: brcm80211@lists.linux.dev Cc: brcm80211-dev-list.pdl@broadcom.com Cc: devicetree@vger.kernel.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-gpio@vger.kernel.org Cc: linux-scsi@vger.kernel.org Cc: linux-nfs@vger.kernel.org Cc: devel@lists.orangefs.org Cc: linux-hardening@vger.kernel.org Cc: linux-sound@vger.kernel.org --- include/linux/fortify-string.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.= h index cf841dc71fef..0b489124bfcb 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -363,7 +363,12 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2) char *strcat(char * const POS p, const char *q) { const size_t p_size =3D __member_size(p); - const size_t wanted =3D strlcat(p, q, p_size); + + if (p_size =3D=3D SIZE_MAX) + return __underlying_strcat(p, q); + + const size_t p_len =3D __fortify_strlen(p); + const size_t wanted =3D p_len + __builtin_snprintf(p + p_len, p_size - p_= len, "%s", q); =20 if (p_size <=3D wanted) fortify_panic(FORTIFY_FUNC_strcat, FORTIFY_WRITE, p_size, wanted + 1, p)= ; --=20 2.55.0.1032.g73a4cd73de-goog