From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793752903; b=WQ/o4ouYtVJiJHc1KN7lSoiDFme5ir+ydFicpL8onUDLyn6wiTE92WaSrVriuc9MquoI Pr7BSdVTIjnPBmcIs9yKf7xbXELzv4UDp+U9u/6hY5PNmC9NP6QRKjFJ/ThXjyxiBF+L0 Dyhur6HUn8SkbAGhJALqMaddFci82Hy8SQJlMrj8tYbcqqhM876CDusLIxhWRCtoaqdGl r6vURmTUTtlrKWwgXa56zIvkssVhZrU+7xaPNP8caDiGTLY48paGZ8+F/yQbB4UsnySeI sNXawRwU+lg2haBLJ0cFi9/aJwenV7dfkZSpOr5uEFY99GzJyx/u5gHPNmF2zlYZYNA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793752903; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=19xl7fcvQ3PRDXDs19M+uQXk3TXZX7+z7U0spFpWAT4=; b=2mZOuq6rqRRXFnDMMIT/fy5wa59ocgdSipSd20SKnZ04+vn8W7xNkrdHG9Jbl/MZkE/i P+2uCzDQSfbCRd9H2xr4xgJTIzpNKpnkkFN3YHE3FvgYMbPYZi72JDehesz85pBwgcfxZ Vx/dtx6A/cj9wyMv/QeZNyuAjisZpB6PHpbdpHyYN7q1FA9DUJUw9E2PNL3Z4bWpnbOph qMDvdNx423HysWPW92SFkpDRr5hRl0vT7eaFV0bre/DPmjEmTCj4fr0Slm6OP6sMquYyc dhRQkZXJfiT04mM4zoBrDXEvxiqNjP9gqOqAyzpEsLSiTche/XjCpUdhTbbpgEztSLA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=MfnZO75s; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FABB606A324 for ; Wed, 4 Nov 2026 00:41:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=MfnZO75s Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DC8B1F00919; Wed, 4 Nov 2026 00:41:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793752902; bh=19xl7fcvQ3PRDXDs19M+uQXk3TXZX7+z7U0spFpWAT4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=MfnZO75sjB8uYI4C95l/hP9sHj1C+kMOQ/4FgTlVSs6MC20XfKgsLhhqG6rL3znti 9iBsq9Cb6BvCJ4hZ6oQhwU1n7NhDB36HmoZEWP55knwBokqMtDkzlwOnH69LfLXhha jPoupFdrnxnR9DUrwTdA2IeqKyl8/m+t/b3JOtOJ0kw3M8+MfUiti+rs7+uUX/Q0AY Sob4OrqnzTm2RsYsTqxHBEquaWfz/GUUJIy/fAT5I1L2BO/6dwQdzQy2g5OBpFgJcZ FLS5gAYDmeBxbxyve/k+rkLZf+1opKZbf9+JZBBBWvEcMHifeohBmUrvfWjXsOmzTJ 6Bz4/5VySf1hw== From: Sasha Levin To: stable@vger.kernel.org Cc: Henry Hu , ChenXiaoSong , Namjae Jeon , Sasha Levin Subject: [PATCH 5.15.y] ksmbd: fix invalid pointer dereference when get_inode_acl() fails Date: Tue, 3 Nov 2026 19:41:41 -0500 Message-ID: <20261104004113.1931761-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026110321-overstuff-recoil-e280@gregkh> References: <2026110321-overstuff-recoil-e280@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Henry Hu [ Upstream commit 19d180c7baab7126af5848ed87d5f7b5add0cef2 ] When get_inode_acl() fails, it returns an ERR_PTR(), but ksmbd_acls_fattr() stored that pointer in smb_fattr without checking for errors. Later callers then passed the error pointer to security descriptor helpers or posix_acl_release(), resulting in an invalid pointer dereference. This was reproduced on an XFS-backed share when xfs_get_acl() returned ERR_PTR(-ENOMEM). Querying the SMB ACL from a CIFS client triggered the crash: BUG: unable to handle page fault for address: fffffffffffffff8 RIP: smb_acl_sec_desc_scratch_len+0x58/0x90 [ksmbd] Call Trace: smb2_query_info+0x40d/0x17c0 [ksmbd] handle_ksmbd_work+0x1ca/0x770 [ksmbd] Fix this by checking the return values from get_inode_acl() in ksmbd_acls_fattr(). Treat -EOPNOTSUPP as indicating that no ACL is available, and propagate all other errors to the callers. Update smb2_open() and smb2_get_info_sec() to handle these errors. Cc: stable@vger.kernel.org Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Assisted-by: Codex:gpt-5.6-sol Reviewed-by: ChenXiaoSong Signed-off-by: Henry Hu Signed-off-by: Namjae Jeon [ sashal: changed get_inode_acl() calls to get_acl() for the older ACL API ] Signed-off-by: Sasha Levin --- fs/ksmbd/smb2pdu.c | 43 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 8 deletions(-) diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index 4c42205fe5261..31dd82c8eb228 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -2686,10 +2686,12 @@ static int smb2_create_sd_buffer(struct ksmbd_work *work, le32_to_cpu(sd_buf->ccontext.DataLength), true, false); } -static void ksmbd_acls_fattr(struct smb_fattr *fattr, - struct user_namespace *mnt_userns, - struct inode *inode) +static int ksmbd_acls_fattr(struct smb_fattr *fattr, + struct user_namespace *mnt_userns, + struct inode *inode) { + struct posix_acl *acl; + fattr->cf_uid = i_uid_into_mnt(mnt_userns, inode); fattr->cf_gid = i_gid_into_mnt(mnt_userns, inode); fattr->cf_mode = inode->i_mode; @@ -2697,10 +2699,28 @@ static void ksmbd_acls_fattr(struct smb_fattr *fattr, fattr->cf_dacls = NULL; if (IS_ENABLED(CONFIG_FS_POSIX_ACL)) { - fattr->cf_acls = get_acl(inode, ACL_TYPE_ACCESS); - if (S_ISDIR(inode->i_mode)) - fattr->cf_dacls = get_acl(inode, ACL_TYPE_DEFAULT); + acl = get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR(acl)) { + if (acl != ERR_PTR(-EOPNOTSUPP)) + return PTR_ERR(acl); + acl = NULL; + } + fattr->cf_acls = acl; + + if (S_ISDIR(inode->i_mode)) { + acl = get_acl(inode, ACL_TYPE_DEFAULT); + if (IS_ERR(acl)) { + if (acl != ERR_PTR(-EOPNOTSUPP)) { + posix_acl_release(fattr->cf_acls); + return PTR_ERR(acl); + } + acl = NULL; + } + fattr->cf_dacls = acl; + } } + + return 0; } /** @@ -3189,7 +3209,10 @@ int smb2_open(struct ksmbd_work *work) struct smb_ntsd *pntsd; int pntsd_size, ace_num = 0; - ksmbd_acls_fattr(&fattr, user_ns, inode); + rc = ksmbd_acls_fattr(&fattr, user_ns, inode); + if (rc) + goto err_out; + if (fattr.cf_acls) ace_num = fattr.cf_acls->a_count; if (fattr.cf_dacls) @@ -5366,7 +5389,11 @@ static int smb2_get_info_sec(struct ksmbd_work *work, user_ns = file_mnt_user_ns(fp->filp); inode = file_inode(fp->filp); - ksmbd_acls_fattr(&fattr, user_ns, inode); + rc = ksmbd_acls_fattr(&fattr, user_ns, inode); + if (rc) { + ksmbd_fd_put(work, fp); + return rc; + } if (test_share_config_flag(work->tcon->share_conf, KSMBD_SHARE_FLAG_ACL_XATTR)) -- 2.53.0