From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f54.google.com (mail-wm1-f54.google.com [209.85.128.54]) (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 57EE5362156 for ; Sun, 31 May 2026 16:18:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780244295; cv=none; b=uqWVKc6Zjk6RtQFi1sS9UMg7mF0Y93u2aVN3YDojZLs4aofU73SxgGcAwCdmFgvZ6Zz0srCTmcZOeDOC5mFhulH3Ktsxo/YwcgySPSnPCAAM51OLlfIgLEUkqHQ/9ZpX4Z07Vww9ZLLXPdNrYD5tmp/pqW2PN0gDcpQMrBoBBog= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780244295; c=relaxed/simple; bh=a8uDziLcsJjjIOde62aXT5Ua5oTmQdmUkktgNMjdJHQ=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=uu3Qlq74G3rd5yQdDiAqCIyDXPxchRBL591p0/09eL7PQqRkQlkabFLZIjHkp8khdGxdaRdNlNiwEhB95Uc57tdAlHJFYdvCjz3XBgkUJq6yJdu4fg6LFBd9KUcDNlrqwr8eOi9aMAe3pXnQicIuQKk58zFpLGNb5WiMubEqWFc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=LkzUguTb; arc=none smtp.client-ip=209.85.128.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="LkzUguTb" Received: by mail-wm1-f54.google.com with SMTP id 5b1f17b1804b1-490a765e68eso4732895e9.1 for ; Sun, 31 May 2026 09:18:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1780244293; x=1780849093; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=P9EIWP7WI7ejnc3HkMg6P5AQBc99pV+sSSiz5HA+rPo=; b=LkzUguTbAny6lKWtJHpG3VdoJd6b2hk1iO36FcUeUkxP6/h7ZHyWYAqGt6TVTxe49N 0A+2Iyyr2ju3/wRSZSKUP/a2/aO+gbQ8x3cX+qPjtZxHoG3QAoQQF0wCBGfAw17koyfl fcICCJKwUQF0P2CRuvhM11lb6ffr6Y8P+slGZxavbIH1m4Ae+rfjoDGRh3SWvdAAQJ0V QyeZdyZI0+0JpZ4vLSiotnk2LEzY8tNPGhzRxQw/wzl+6teACsmHJ7ddc2YxaJs7zOlu FxMTBhAunB0LZXFqwfdFZ0KhSAuDQx4djolu5n9A12F/KyZun85UB5K0E9PMhcMULde5 nE6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780244293; x=1780849093; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=P9EIWP7WI7ejnc3HkMg6P5AQBc99pV+sSSiz5HA+rPo=; b=ed6+QoP5go7Peb4VXP2QeRuY/04mQRXtXgs4uahnDpMSl0wJ+4XvQlLLDWGFPRc3mg wPR/7i3+qn/7wgRhF+jkx9djPCH/aQbcjN5yaNcRQ0qN11p9ugzf+zu/KZBaghhgyI8K HcAUXgMlMZfc/COxLF4AySxcvgcK86OG99xkmSFnfLIgRHquu1+/12OzQpavbBFs0fE8 XvCXlsw7rcLXCXyuBcJb8ffa/QEsF5i2bw1/r+jWNNmM+zq0g4DzqSDu3L4HbmXKN3mJ yWAFJFEqglhWesVbsngM5F04eXulTZcr9aAQ5pa8FaeocHpavAwdbpW6R9kXZsI0w8UD 9zjw== X-Forwarded-Encrypted: i=1; AFNElJ8Srju8b67+IMD9Eh4uoJ9x3NLIdwMlmDIYErg9bSEPXjPnwlU1f090U5J9a5G2E/f3o4frWe4Z@vger.kernel.org X-Gm-Message-State: AOJu0Yzenq5K1SrCWXSjDK4XQgtNAKQlUwx8o+vsp+mGsfkvMW/zJVyZ QfTvdbQ/bqgMFfHIssBspt22uIV61LHD3kqTMR1aU1iurATKtQO0ZArV X-Gm-Gg: Acq92OGJCv8PTKqkFRxS044s6pCMs/B5VIhjxcgH9yeoWnXZYHOCBjpBwWekYEDadgx d77+zT4ZeK6SHCKU5OX87wet8c+PxUlIbPtWmtSRRVAnQkU+UL0viEUEUYnrXyd0kAxpV1b+H+y qSCC/1nHCaMmZWtoYiBW+LZRZff3n1YOxSzXmiAu0RYbejqm2oDBoULUt9E5dGEwxiCFqkyPa2W o7LMnzQZ/MdgXyvWhyfHgZ5yrxHe42KbrAuACTC5UVkhl/WVJQo8Z8SUBF1iH42vE0IYvnjaRtn +/sPLvIO1yovER/HgD8VVyhTqZtfGR0jEyD7M7bg1dQseazwuVH3W8xTg+9hPMZ6JHT9RgKJm+I X7YX6IhkY2U/JefSsj02aGWTRmD/oqj3C2pP93URlLoybP2sLfZv7vXoeuLNXg7QCeG4sP6R7va D5+9AR1CasV77/Z6O9Sw4/5tawwbnE+jqFyZfihE+kS621Ttc6FMZT1NRb3RhNl02jf5mxGEk= X-Received: by 2002:a05:600d:8497:10b0:490:6869:9601 with SMTP id 5b1f17b1804b1-490a292a48fmr95653825e9.6.1780244292718; Sun, 31 May 2026 09:18:12 -0700 (PDT) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4909ca6e124sm191663255e9.7.2026.05.31.09.18.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 31 May 2026 09:18:12 -0700 (PDT) Date: Sun, 31 May 2026 17:18:11 +0100 From: David Laight To: Mike Rapoport Cc: Paul Moore , Stephen Smalley , Ondrej Mosnacek , Venkat Rao Bagalkote , selinux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] selinux: hooks: use kmalloc() to allocate path buffer Message-ID: <20260531171811.16abb087@pumpkin> In-Reply-To: <20260531151502.1467515-1-rppt@kernel.org> References: <20260531151502.1467515-1-rppt@kernel.org> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: selinux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sun, 31 May 2026 18:15:02 +0300 Mike Rapoport wrote: > From: "Mike Rapoport (Microsoft)" > > selinux_genfs_get_sid() allocates memory for a path with __get_free_page(). > > Such usage does not require a "page" and the size of the buffer should > actually be PATH_MAX which may be less than PAGE_SIZE on some > architectures. > > Replace __get_free_page() for allocation of a path buffer with kmalloc() > and make it explicit that the buffer size is PATH_MAX. > > Signed-off-by: Mike Rapoport (Microsoft) > --- > v2 changes: > * explicitly use kmalloc() with PATH_MAX > > security/selinux/hooks.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 0f704380a8c8..19493198ece1 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -1336,11 +1336,11 @@ static int selinux_genfs_get_sid(struct dentry *dentry, > struct super_block *sb = dentry->d_sb; > char *buffer, *path; > > - buffer = (char *)__get_free_page(GFP_KERNEL); > + buffer = kmalloc(GFP_KERNEL, PATH_MAX); At least get the args in the right order. > if (!buffer) > return -ENOMEM; > > - path = dentry_path_raw(dentry, buffer, PAGE_SIZE); > + path = dentry_path_raw(dentry, buffer, PATH_MAX); > if (IS_ERR(path)) > rc = PTR_ERR(path); > else { > @@ -1361,7 +1361,7 @@ static int selinux_genfs_get_sid(struct dentry *dentry, > rc = 0; > } > } > - free_page((unsigned long)buffer); > + kfree(buffer); > return rc; > } >