linux-kernel - [PATCH] smb: client: correctly handle ErrorContextData as a flexible array

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20250116072948.682402-1-buaajxlj@163.com>
Date: Thu, 16 Jan 2025 15:29:48 +0800
From: Liang Jie <buaajxlj@....com>
To: sfrench@...ba.org
Cc: pc@...guebit.com,
	ronniesahlberg@...il.com,
	sprasad@...rosoft.com,
	tom@...pey.com,
	bharathsm@...rosoft.com,
	linux-cifs@...r.kernel.org,
	samba-technical@...ts.samba.org,
	linux-kernel@...r.kernel.org,
	Liang Jie <liangjie@...iang.com>
Subject: [PATCH] smb: client: correctly handle ErrorContextData as a flexible array

From: Liang Jie <liangjie@...iang.com>

The `smb2_symlink_err_rsp` structure was previously defined with
`ErrorContextData` as a single `__u8` byte. However, the `ErrorContextData`
field is intended to be a variable-length array based on `ErrorDataLength`.
This mismatch leads to incorrect pointer arithmetic and potential memory
access issues when processing error contexts.

Updates the `ErrorContextData` field to be a flexible array
(`__u8 ErrorContextData[]`). Additionally, it modifies the corresponding
casts in the `symlink_data()` function to properly handle the flexible
array, ensuring correct memory calculations and data handling.

These changes improve the robustness of SMB2 symlink error processing.

Signed-off-by: Liang Jie <liangjie@...iang.com>
---
 fs/smb/client/smb2file.c | 4 ++--
 fs/smb/client/smb2pdu.h  | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/smb/client/smb2file.c b/fs/smb/client/smb2file.c
index e836bc2193dd..9ec44eab8dbc 100644
--- a/fs/smb/client/smb2file.c
+++ b/fs/smb/client/smb2file.c
@@ -42,14 +42,14 @@ static struct smb2_symlink_err_rsp *symlink_data(const struct kvec *iov)
 		end = (struct smb2_error_context_rsp *)((u8 *)err + iov->iov_len);
 		do {
 			if (le32_to_cpu(p->ErrorId) == SMB2_ERROR_ID_DEFAULT) {
-				sym = (struct smb2_symlink_err_rsp *)&p->ErrorContextData;
+				sym = (struct smb2_symlink_err_rsp *)p->ErrorContextData;
 				break;
 			}
 			cifs_dbg(FYI, "%s: skipping unhandled error context: 0x%x\n",
 				 __func__, le32_to_cpu(p->ErrorId));
 
 			len = ALIGN(le32_to_cpu(p->ErrorDataLength), 8);
-			p = (struct smb2_error_context_rsp *)((u8 *)&p->ErrorContextData + len);
+			p = (struct smb2_error_context_rsp *)(p->ErrorContextData + len);
 		} while (p < end);
 	} else if (le32_to_cpu(err->ByteCount) >= sizeof(*sym) &&
 		   iov->iov_len >= SMB2_SYMLINK_STRUCT_SIZE) {
diff --git a/fs/smb/client/smb2pdu.h b/fs/smb/client/smb2pdu.h
index 076d9e83e1a0..ba2696352634 100644
--- a/fs/smb/client/smb2pdu.h
+++ b/fs/smb/client/smb2pdu.h
@@ -79,7 +79,7 @@ struct smb2_symlink_err_rsp {
 struct smb2_error_context_rsp {
 	__le32 ErrorDataLength;
 	__le32 ErrorId;
-	__u8  ErrorContextData; /* ErrorDataLength long array */
+	__u8  ErrorContextData[]; /* ErrorDataLength long array */
 } __packed;
 
 /* ErrorId values */
-- 
2.25.1