From nobody Thu Apr 10 19:02:24 2025 Received: from cstnet.cn (smtp84.cstnet.cn [159.226.251.84]) (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 715C0204875; Tue, 1 Apr 2025 15:19:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.84 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743520765; cv=none; b=HrrG0v3GK6RIWps/+y3Mu+CWxAmUb70TTQOZjt7q3Q8whr4SsjnvKWDIcLLuChwm+qdTlj7Nc2k38StflVKTfivK1hx5i5U78XNTDz2MrwtuDZwHxQwZ3rINiuybFj7knnDA+4Y447hC4RAtHS95CEVuy+MYDHJGXzs1tDR+H44= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743520765; c=relaxed/simple; bh=UDBLdp3G5XLl9adnfAstrrZW/PBho8d/rc6SWcjR6WE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=cYRnwv5fSopt8ncrwlVkYbcRjKBQSdUdObmPckJRCfOpGLRrXSHvRDQ9frQjb8e2S2+LtcP0ElSpq7wwt6VEU6AvFMSOPQ2M+pnZ7Sb2mHz55BMlJrP5mNvJt6FUZhT6NJhqcdXiam6pEWh83gEtrp/WLA609XS3vPCkdn79rY4= 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=159.226.251.84 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 localhost.localdomain (unknown [124.16.141.245]) by APP-05 (Coremail) with SMTP id zQCowADnIwz0A+xnSRjGBA--.10747S2; Tue, 01 Apr 2025 23:19:18 +0800 (CST) From: Wentao Liang To: gregkh@linuxfoundation.org, tj@kernel.org Cc: linux-kernel@vger.kernel.org, Wentao Liang , stable@vger.kernel.org Subject: [PATCH] kernfs: fix potential NULL dereference in mmap handler Date: Tue, 1 Apr 2025 23:18:59 +0800 Message-ID: <20250401151859.2842-1-vulab@iscas.ac.cn> X-Mailer: git-send-email 2.42.0.windows.2 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: zQCowADnIwz0A+xnSRjGBA--.10747S2 X-Coremail-Antispam: 1UD129KBjvdXoWrtr4DKFWkAF1fJFWrCr45KFg_yoWkurc_Jr 95CrZ8Wr4UXF1avF1ayws3Zr9aqaykZr1Fya15t3yUtws8t3s7Gr95u3Zrur4DJrWUGr4D Aw1DCr90vr17CjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbcAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8w A2z4x0Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Jr0_ Gr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s 1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0 cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r4j6F4UMcvjeVCFs4IE7xkEbVWUJVW8Jw ACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc7CjxVAaw2AFwI0_JF0_ Jw1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxV WUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI 7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r 1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI 42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfU8miiUUUUU X-CM-SenderInfo: pyxotu46lvutnvoduhdfq/1tbiBwsTA2fr2Gl+eQAAsm Content-Type: text/plain; charset="utf-8" The kernfs_fop_mmap() invokes the '->mmap' callback without verifying its existence. This leads to a NULL pointer dereference when the kernfs node does not define the operation, resulting in an invalid memory access. Add a check to ensure the '->mmap' callback is present before invocation. Return -EINVAL when uninitialized to prevent the invalid access. Fixes: 324a56e16e44 ("kernfs: s/sysfs_dirent/kernfs_node/ and rename its fr= iends accordingly") Cc: stable@vger.kernel.org # 3.14+ Signed-off-by: Wentao Liang --- fs/kernfs/file.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index 8502ef68459b..7d8434a97487 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -459,9 +459,14 @@ static int kernfs_fop_mmap(struct file *file, struct v= m_area_struct *vma) goto out_unlock; =20 ops =3D kernfs_ops(of->kn); - rc =3D ops->mmap(of, vma); - if (rc) + if (ops->mmap) { + rc =3D ops->mmap(of, vma); + if (rc) + goto out_put; + } else { + rc =3D -EINVAL; goto out_put; + } =20 /* * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup() --=20 2.42.0.windows.2