[PATCH 6.6 022/102] cifs: get rid of dup length check in parse_reparse_point()

Greg Kroah-Hartman
2024-05-23T13:24:48Z

From: Paulo Alcantara <pc@manguebit.com>

[ Upstream commit 8a3c4e44c243308c2364a00f9944c3d6fbdeb125 ]

smb2_compound_op(SMB2_OP_GET_REPARSE) already checks if ioctl response
has a valid reparse data buffer's length, so there's no need to check
it again in parse_reparse_point().

In order to get rid of duplicate check, validate reparse data buffer's
length also in cifs_query_reparse_point().

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/smb/client/cifssmb.c | 14 ++++++++++++--
fs/smb/client/smb2ops.c | 12 ------------
2 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c
index e9e33b0b3ac47..01e89070df5ab 100644
--- a/fs/smb/client/cifssmb.c
+++ b/fs/smb/client/cifssmb.c
@@ -2700,11 +2700,12 @@ int cifs_query_reparse_point(const unsigned int xid,
u32 *tag, struct kvec *rsp,
int *rsp_buftype)
{
+ struct reparse_data_buffer *buf;
struct cifs_open_parms oparms;
TRANSACT_IOCTL_REQ *io_req = NULL;
TRANSACT_IOCTL_RSP *io_rsp = NULL;
struct cifs_fid fid;
- __u32 data_offset, data_count;
+ __u32 data_offset, data_count, len;
__u8 *start, *end;
int io_rsp_len;
int oplock = 0;
@@ -2774,7 +2775,16 @@ int cifs_query_reparse_point(const unsigned int xid,
goto error;
}

- *tag = le32_to_cpu(((struct reparse_data_buffer *)start)->ReparseTag);
+ data_count = le16_to_cpu(io_rsp->ByteCount);
+ buf = (struct reparse_data_buffer *)start;
+ len = sizeof(*buf);
+ if (data_count < len ||
+ data_count < le16_to_cpu(buf->ReparseDataLength) + len) {
+ rc = -EIO;
+ goto error;
+ }
+
+ *tag = le32_to_cpu(buf->ReparseTag);
rsp->iov_base = io_rsp;
rsp->iov_len = io_rsp_len;
*rsp_buftype = CIFS_LARGE_BUFFER;
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 9b7cdb7d7ece8..3e07ab1564ea7 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -2946,18 +2946,6 @@ int parse_reparse_point(struct reparse_data_buffer *buf,
u32 plen, struct cifs_sb_info *cifs_sb,
bool unicode, struct cifs_open_info_data *data)
{
- if (plen < sizeof(*buf)) {
- cifs_dbg(VFS, "%s: reparse buffer is too small. Must be at least 8 bytes but was %d\n",
- __func__, plen);
- return -EIO;
- }
-
- if (plen < le16_to_cpu(buf->ReparseDataLength) + sizeof(*buf)) {
- cifs_dbg(VFS, "%s: invalid reparse buf length: %d\n",
- __func__, plen);
- return -EIO;
- }
-
data->reparse.buf = buf;

/* See MS-FSCC 2.1.2 */
--
2.43.0