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=1793745575; b=lPTXO18T5j26nfGhgRXzCv/hQw525Atraxl+eoRmhDiTXdw7rNWZXJNADFMGKLDEmqOA 4o5BRU2UUyDrz401ReuIS3MplN62cJ6cSJNvXRAUupY+oeSniJVD8u/ED8GqPnhNwBPox bGHHv5pXE3R/VRDfHFzxbr5ZVHowtQGgk45J9xSTV1L9y4c+McVTv5P7iFhKUrjZEPvRK NafyDKGE+mVI3lkYncyYn6Fd7q1W9ITDWDc+l3FiukVqU+1W/LoF+05KYXF6XC+LutIFs bCfzlSBsOX8aQ3Q3vbfk26ZSryGMlfJcO0g8/IjzzAkCbnpIp2Nj6q2P68EsLa1A+vw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793745575; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=J2AMHa3hASkzJq1pQt2qLr4jbamNJFcltEZGfKdU4MQ=; b=xyuBJw9GWPtDHGnOWiud4ZBug6O+a6Tp3VDSeQObED0p4bgzrkD/OgfmDOtavEYmCPuh 4t9K5kG8wDgzhWKxfVbAjJIYNmhotBJ6MsMjcQNjtacE5GPKepWDaEH/qskwCSF5+4XGm en5aIxzhVh82MU7KbqUnPxyy8tfCqO+/8QmLuoknMm8zLJD5ujSM8skUUtScArU2yl54O C2qNAALKLye4wObaoG3c55GZ/5yFaOCg/V0Wt//nA8eqP0BoCU7WS9lsz4ixE9FkeLdM8 bksEj2LnTOZ9ao77K82bj8+Zp0ZyzNEtN3SEIvzEOhc4ZhQqChZImDt7hHkBdTNDrTw== 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=jdTc62Lg; 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 80A93606A324 for ; Tue, 3 Nov 2026 22:39:35 +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=jdTc62Lg Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85F771F000C1; Tue, 3 Nov 2026 22:39:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793745575; bh=J2AMHa3hASkzJq1pQt2qLr4jbamNJFcltEZGfKdU4MQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jdTc62Lgy3UqntLaMBEL9OfcZf2FCV9ig7EJkvs1SGeUEJVQIG7ZoywdLOOCBz9nO UkxYVhaVOp1XuqIm0sr3H7BfO8hhEEShRrpnSiKeQegzVjxi+9ZCxb55jDO42K9UZH C09uDM0lZrMqZ7J3I3FnQD0Rpb/0Eke0bPOfEYc8rjKQRwr1R8LW8FvNYlLHmR38OJ r3t0QbryYrKKxWPUIvHTw6q5OYXHUiHTlBp2I8px9p/q8Kmtw7xB5Wd3a7jTmZlSTL ATpzsJs72tcEtk3VS2b02XY6VLAr1qpvhvh+lsby6lNTsF1EV9vZnFvyPhqc1ADBFo T7N+Rd+t+4Lpg== From: Sasha Levin To: stable@vger.kernel.org Cc: Henry Hu , ChenXiaoSong , Namjae Jeon , Sasha Levin Subject: [PATCH 6.6.y] ksmbd: fix invalid pointer dereference when get_inode_acl() fails Date: Tue, 3 Nov 2026 17:39:33 -0500 Message-ID: <20261103223846.1547932-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026110320-hydration-wreath-8606@gregkh> References: <2026110320-hydration-wreath-8606@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: adapted ksmbd_acls_fattr() to use a non-const mnt_idmap parameter ] Signed-off-by: Sasha Levin --- fs/smb/server/smb2pdu.c | 42 +++++++++++++++++++++++++++++++++-------- 1 file changed, 34 insertions(+), 8 deletions(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index aaccef2e3f3bb..b6af38af337dd 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -2696,10 +2696,11 @@ 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 mnt_idmap *idmap, - struct inode *inode) +static int ksmbd_acls_fattr(struct smb_fattr *fattr, + struct mnt_idmap *idmap, + struct inode *inode) { + struct posix_acl *acl; vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode); vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode); @@ -2710,10 +2711,28 @@ static void ksmbd_acls_fattr(struct smb_fattr *fattr, fattr->cf_dacls = NULL; if (IS_ENABLED(CONFIG_FS_POSIX_ACL)) { - fattr->cf_acls = get_inode_acl(inode, ACL_TYPE_ACCESS); - if (S_ISDIR(inode->i_mode)) - fattr->cf_dacls = get_inode_acl(inode, ACL_TYPE_DEFAULT); + acl = get_inode_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_inode_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; } enum { @@ -3446,7 +3465,10 @@ int smb2_open(struct ksmbd_work *work) int pntsd_size; size_t scratch_len; - ksmbd_acls_fattr(&fattr, idmap, inode); + rc = ksmbd_acls_fattr(&fattr, idmap, inode); + if (rc) + goto err_out; + scratch_len = smb_acl_sec_desc_scratch_len(&fattr, NULL, 0, OWNER_SECINFO | GROUP_SECINFO | @@ -5900,7 +5922,11 @@ static int smb2_get_info_sec(struct ksmbd_work *work, idmap = file_mnt_idmap(fp->filp); inode = file_inode(fp->filp); - ksmbd_acls_fattr(&fattr, idmap, inode); + rc = ksmbd_acls_fattr(&fattr, idmap, 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