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cifs: Fix changing times and read-only attr over SMB1 smb_set_file_info() function

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[ Upstream commit f122121796f91168d0894c2710b8dd71330a34f8 ]

Function CIFSSMBSetPathInfo() is not supported by non-NT servers and
returns error. Fallback code via open filehandle and CIFSSMBSetFileInfo()
does not work neither because CIFS_open() works also only on NT server.

Therefore currently the whole smb_set_file_info() function as a SMB1
callback for the ->set_file_info() does not work with older non-NT SMB
servers, like Win9x and others.

This change implements fallback code in smb_set_file_info() which will
works with any server and allows to change time values and also to set or
clear read-only attributes.

To make existing fallback code via CIFSSMBSetFileInfo() working with also
non-NT servers, it is needed to change open function from CIFS_open()
(which is NT specific) to cifs_open_file() which works with any server
(this is just a open wrapper function which choose the correct open
function supported by the server).

CIFSSMBSetFileInfo() is working also on non-NT servers, but zero time
values are not treated specially. So first it is needed to fill all time
values if some of them are missing, via cifs_query_path_info() call.

There is another issue, opening file in write-mode (needed for changing
attributes) is not possible when the file has read-only attribute set.
The only option how to clear read-only attribute is via SMB_COM_SETATTR
command. And opening directory is not possible neither and here the
SMB_COM_SETATTR command is the only option how to change attributes.
And CIFSSMBSetFileInfo() does not honor setting read-only attribute, so
for setting is also needed to use SMB_COM_SETATTR command.

Existing code in cifs_query_path_info() is already using SMB_COM_GETATTR as
a fallback code path (function SMBQueryInformation()), so introduce a new
function SMBSetInformation which will implement SMB_COM_SETATTR command.

My testing showed that Windows XP SMB1 client is also using SMB_COM_SETATTR
command for setting or clearing read-only attribute against non-NT server.
So this can prove that this is the correct way how to do it.

With this change it is possible set all 4 time values and all attributes,
including clearing and setting read-only bit on non-NT SMB servers.
Tested against Win98 SMB1 server.

This change fixes "touch" command which was failing when called on existing
file. And fixes also "chmod +w" and "chmod -w" commands which were also
failing (as they are changing read-only attribute).

Note that this change depends on following change
"cifs: Improve cifs_query_path_info() and cifs_query_file_info()"
as it require to query all 4 time attribute values.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Pali Rohár
2024-12-30 21:32:39 +01:00
committed by Greg Kroah-Hartman
parent 0a9920e1ff
commit 6b1a9a7647
4 changed files with 166 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
fs/smb/client/cifspdu.h
View File

@@ -1226,10 +1226,9 @@ typedef struct smb_com_query_information_rsp {
typedef struct smb_com_setattr_req {
struct smb_hdr hdr; /* wct = 8 */
__le16 attr;
__le16 time_low;
__le16 time_high;
__le32 last_write_time;
__le16 reserved[5]; /* must be zero */
__u16 ByteCount;
__le16 ByteCount;
__u8 BufferFormat; /* 4 = ASCII */
unsigned char fileName[];
} __attribute__((packed)) SETATTR_REQ;

4
fs/smb/client/cifsproto.h
View File

@@ -396,6 +396,10 @@ extern int CIFSSMBQFSUnixInfo(const unsigned int xid, struct cifs_tcon *tcon);
extern int CIFSSMBQFSPosixInfo(const unsigned int xid, struct cifs_tcon *tcon,
struct kstatfs *FSData);
extern int SMBSetInformation(const unsigned int xid, struct cifs_tcon *tcon,
const char *fileName, __le32 attributes, __le64 write_time,
const struct nls_table *nls_codepage,
struct cifs_sb_info *cifs_sb);
extern int CIFSSMBSetPathInfo(const unsigned int xid, struct cifs_tcon *tcon,
const char *fileName, const FILE_BASIC_INFO *data,
const struct nls_table *nls_codepage,

57
fs/smb/client/cifssmb.c
View File

@@ -5199,6 +5199,63 @@ CIFSSMBSetFileSize(const unsigned int xid, struct cifs_tcon *tcon,
return rc;
}
int
SMBSetInformation(const unsigned int xid, struct cifs_tcon *tcon,
const char *fileName, __le32 attributes, __le64 write_time,
const struct nls_table *nls_codepage,
struct cifs_sb_info *cifs_sb)
{
SETATTR_REQ *pSMB;
SETATTR_RSP *pSMBr;
struct timespec64 ts;
int bytes_returned;
int name_len;
int rc;
cifs_dbg(FYI, "In %s path %s\n", __func__, fileName);
retry:
rc = smb_init(SMB_COM_SETATTR, 8, tcon, (void **) &pSMB,
(void **) &pSMBr);
if (rc)
return rc;
if (pSMB->hdr.Flags2 & SMBFLG2_UNICODE) {
name_len =
cifsConvertToUTF16((__le16 *) pSMB->fileName,
fileName, PATH_MAX, nls_codepage,
cifs_remap(cifs_sb));
name_len++; /* trailing null */
name_len *= 2;
} else {
name_len = copy_path_name(pSMB->fileName, fileName);
}
/* Only few attributes can be set by this command, others are not accepted by Win9x. */
pSMB->attr = cpu_to_le16(le32_to_cpu(attributes) &
(ATTR_READONLY | ATTR_HIDDEN | ATTR_SYSTEM | ATTR_ARCHIVE));
/* Zero write time value (in both NT and SETATTR formats) means to not change it. */
if (le64_to_cpu(write_time) != 0) {
ts = cifs_NTtimeToUnix(write_time);
pSMB->last_write_time = cpu_to_le32(ts.tv_sec);
}
pSMB->BufferFormat = 0x04;
name_len++; /* account for buffer type byte */
inc_rfc1001_len(pSMB, (__u16)name_len);
pSMB->ByteCount = cpu_to_le16(name_len);
rc = SendReceive(xid, tcon->ses, (struct smb_hdr *) pSMB,
(struct smb_hdr *) pSMBr, &bytes_returned, 0);
if (rc)
cifs_dbg(FYI, "Send error in %s = %d\n", __func__, rc);
cifs_buf_release(pSMB);
if (rc == -EAGAIN)
goto retry;
return rc;
}
/* Some legacy servers such as NT4 require that the file times be set on
an open handle, rather than by pathname - this is awkward due to
potential access conflicts on the open, but it is unavoidable for these

112
fs/smb/client/smb1ops.c
View File

@@ -912,6 +912,9 @@ smb_set_file_info(struct inode *inode, const char *full_path,
struct cifs_fid fid;
struct cifs_open_parms oparms;
struct cifsFileInfo *open_file;
FILE_BASIC_INFO new_buf;
struct cifs_open_info_data query_data;
__le64 write_time = buf->LastWriteTime;
struct cifsInodeInfo *cinode = CIFS_I(inode);
struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
struct tcon_link *tlink = NULL;
@@ -919,20 +922,58 @@ smb_set_file_info(struct inode *inode, const char *full_path,
/* if the file is already open for write, just use that fileid */
open_file = find_writable_file(cinode, FIND_WR_FSUID_ONLY);
if (open_file) {
fid.netfid = open_file->fid.netfid;
netpid = open_file->pid;
tcon = tlink_tcon(open_file->tlink);
goto set_via_filehandle;
} else {
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink)) {
rc = PTR_ERR(tlink);
tlink = NULL;
goto out;
}
tcon = tlink_tcon(tlink);
}
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink)) {
rc = PTR_ERR(tlink);
tlink = NULL;
goto out;
/*
* Non-NT servers interprets zero time value in SMB_SET_FILE_BASIC_INFO
* over TRANS2_SET_FILE_INFORMATION as a valid time value. NT servers
* interprets zero time value as do not change existing value on server.
* API of ->set_file_info() callback expects that zero time value has
* the NT meaning - do not change. Therefore if server is non-NT and
* some time values in "buf" are zero, then fetch missing time values.
*/
if (!(tcon->ses->capabilities & CAP_NT_SMBS) &&
(!buf->CreationTime || !buf->LastAccessTime ||
!buf->LastWriteTime || !buf->ChangeTime)) {
rc = cifs_query_path_info(xid, tcon, cifs_sb, full_path, &query_data);
if (rc) {
if (open_file) {
cifsFileInfo_put(open_file);
open_file = NULL;
}
goto out;
}
/*
* Original write_time from buf->LastWriteTime is preserved
* as SMBSetInformation() interprets zero as do not change.
*/
new_buf = *buf;
buf = &new_buf;
if (!buf->CreationTime)
buf->CreationTime = query_data.fi.CreationTime;
if (!buf->LastAccessTime)
buf->LastAccessTime = query_data.fi.LastAccessTime;
if (!buf->LastWriteTime)
buf->LastWriteTime = query_data.fi.LastWriteTime;
if (!buf->ChangeTime)
buf->ChangeTime = query_data.fi.ChangeTime;
}
tcon = tlink_tcon(tlink);
if (open_file)
goto set_via_filehandle;
rc = CIFSSMBSetPathInfo(xid, tcon, full_path, buf, cifs_sb->local_nls,
cifs_sb);
@@ -953,8 +994,45 @@ smb_set_file_info(struct inode *inode, const char *full_path,
.fid = &fid,
};
cifs_dbg(FYI, "calling SetFileInfo since SetPathInfo for times not supported by this server\n");
rc = CIFS_open(xid, &oparms, &oplock, NULL);
if (S_ISDIR(inode->i_mode) && !(tcon->ses->capabilities & CAP_NT_SMBS)) {
/* Opening directory path is not possible on non-NT servers. */
rc = -EOPNOTSUPP;
} else {
/*
* Use cifs_open_file() instead of CIFS_open() as the
* cifs_open_file() selects the correct function which
* works also on non-NT servers.
*/
rc = cifs_open_file(xid, &oparms, &oplock, NULL);
/*
* Opening path for writing on non-NT servers is not
* possible when the read-only attribute is already set.
* Non-NT server in this case returns -EACCES. For those
* servers the only possible way how to clear the read-only
* bit is via SMB_COM_SETATTR command.
*/
if (rc == -EACCES &&
(cinode->cifsAttrs & ATTR_READONLY) &&
le32_to_cpu(buf->Attributes) != 0 && /* 0 = do not change attrs */
!(le32_to_cpu(buf->Attributes) & ATTR_READONLY) &&
!(tcon->ses->capabilities & CAP_NT_SMBS))
rc = -EOPNOTSUPP;
}
/* Fallback to SMB_COM_SETATTR command when absolutelty needed. */
if (rc == -EOPNOTSUPP) {
cifs_dbg(FYI, "calling SetInformation since SetPathInfo for attrs/times not supported by this server\n");
rc = SMBSetInformation(xid, tcon, full_path,
buf->Attributes != 0 ? buf->Attributes : cpu_to_le32(cinode->cifsAttrs),
write_time,
cifs_sb->local_nls, cifs_sb);
if (rc == 0)
cinode->cifsAttrs = le32_to_cpu(buf->Attributes);
else
rc = -EACCES;
goto out;
}
if (rc != 0) {
if (rc == -EIO)
rc = -EINVAL;
@@ -962,6 +1040,7 @@ smb_set_file_info(struct inode *inode, const char *full_path,
}
netpid = current->tgid;
cifs_dbg(FYI, "calling SetFileInfo since SetPathInfo for attrs/times not supported by this server\n");
set_via_filehandle:
rc = CIFSSMBSetFileInfo(xid, tcon, buf, fid.netfid, netpid);
@@ -972,6 +1051,21 @@ set_via_filehandle:
CIFSSMBClose(xid, tcon, fid.netfid);
else
cifsFileInfo_put(open_file);
/*
* Setting the read-only bit is not honered on non-NT servers when done
* via open-semantics. So for setting it, use SMB_COM_SETATTR command.
* This command works only after the file is closed, so use it only when
* operation was called without the filehandle.
*/
if (open_file == NULL &&
!(tcon->ses->capabilities & CAP_NT_SMBS) &&
le32_to_cpu(buf->Attributes) & ATTR_READONLY) {
SMBSetInformation(xid, tcon, full_path,
buf->Attributes,
0 /* do not change write time */,
cifs_sb->local_nls, cifs_sb);
}
out:
if (tlink != NULL)
cifs_put_tlink(tlink);