From nobody Fri Apr 10 06:24:12 2026 Received: from cstnet.cn (smtp81.cstnet.cn [159.226.251.81]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81B471B041E; Mon, 24 Feb 2025 13:30:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.81 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740403838; cv=none; b=YFH4cubRP53YdeKS4Lb6Ukwo8591dJVxhRi5I3eDHpfgGoTJ9Hi1pkf+glha3sYo5NpmC3neXyv9aLq6pHWAbeHlXhm2coHUclwb9jv3CjUHGnIWpC8a69qnDOlX5SSHVs7gnF+z2q+e5o/ljqfqEbKU64M12+AKJgvsIbGRozM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740403838; c=relaxed/simple; bh=ABZeoDoCXyMZznzUxsqlycvSyByLRS8r9I1i4W5KKZ0=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=G/T/mou8GGv9LrYmfeHDrfjtbJqX3Srr2bIMAiaR3KAyQZ0/C7v/bCU7E0S5JZd4jmBm+rp1N6fOpEfhkCw5WX31MWKav4TR4FOqR+e3wJC6Hd6lRNFbtqNyLg1MDAyg4ic2ogTeSEvhdnrsdRgBHJ6sGGGFBOkv8dDoZo91NvM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from icess-ProLiant-DL380-Gen10.. (unknown [183.174.60.14]) by APP-03 (Coremail) with SMTP id rQCowAAnLAxldLxnkjsEEA--.4476S2; Mon, 24 Feb 2025 21:30:17 +0800 (CST) From: Ma Ke To: miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, David.Woodhouse@intel.com, jarkko.lavinen@nokia.com Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, Ma Ke , stable@vger.kernel.org Subject: [PATCH] mtd: Fix potential UAF for mtdswap_dev pointers Date: Mon, 24 Feb 2025 21:30:07 +0800 Message-Id: <20250224133007.3037357-1-make24@iscas.ac.cn> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: rQCowAAnLAxldLxnkjsEEA--.4476S2 X-Coremail-Antispam: 1UD129KBjvJXoW7CFyrtr13trWrGF4ftry7Jrb_yoW8GF1UpF Z8CrWay398Jw1fG3ZrAw4DAFyFkw15urW5Gr4rJ3y2vwn5A34fAr90vayY9Fy3KF4DKa4Y qrsFqr98Wr1rGaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvC14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r1j6r1xM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2vYz4IE04k24VAvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI 64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8Jw Am72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAG YxC7MxkF7I0En4kS14v26r1q6r43MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r 1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CE b7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0x vE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAI cVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2Kf nxnUUI43ZEXa7VUbQVy7UUUUU== X-CM-SenderInfo: ppdnvj2u6l2u1dvotugofq/ Content-Type: text/plain; charset="utf-8" In the mtdswap_init(), if the allocations fail, the error handling path frees d->page_buf, d->eb_data, d->revmap and d->page_data without setting these pointers to NULL. This could lead to UAF if subsequent error handling or device reset operations attempt to release these pointers again. Set d->page_buf, d->eb_data, d->revmap and d->page_data to NULL immediately after freeing them to prevent misuse. Release immediately and set to NULL, adhering to the 'release implies invalid' defensive programming principle. Found by code review. Cc: stable@vger.kernel.org Fixes: a32159024620 ("mtd: Add mtdswap block driver") Signed-off-by: Ma Ke --- drivers/mtd/mtdswap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/mtd/mtdswap.c b/drivers/mtd/mtdswap.c index 680366616da2..b315dab2a914 100644 --- a/drivers/mtd/mtdswap.c +++ b/drivers/mtd/mtdswap.c @@ -1318,12 +1318,16 @@ static int mtdswap_init(struct mtdswap_dev *d, unsi= gned int eblocks, =20 oob_buf_fail: kfree(d->page_buf); + d->page_buf =3D NULL; page_buf_fail: vfree(d->eb_data); + d->eb_data =3D NULL; eb_data_fail: vfree(d->revmap); + d->revmap =3D NULL; revmap_fail: vfree(d->page_data); + d->page_data =3D NULL; page_data_fail: printk(KERN_ERR "%s: init failed (%d)\n", MTDSWAP_PREFIX, ret); return ret; --=20 2.25.1