[PATCH AUTOSEL 6.12 04/18] smb: server: smb2pdu: check return value of xa_store()

[PATCH AUTOSEL 6.12 04/18] smb: server: smb2pdu: check return value of xa_store()

[Sasha Levin]

From: Salah Triki <salah.triki@gmail.com>

[ Upstream commit af5226abb40cae959f424f7ca614787a1c87ce48 ]

xa_store() may fail so check its return value and return error code if
error occurred.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/server/smb2pdu.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 6b9286c963439..f52afb01175dd 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -1443,7 +1443,7 @@ static int ntlm_authenticate(struct ksmbd_work *work,
 {
 	struct ksmbd_conn *conn = work->conn;
 	struct ksmbd_session *sess = work->sess;
-	struct channel *chann = NULL;
+	struct channel *chann = NULL, *old;
 	struct ksmbd_user *user;
 	u64 prev_id;
 	int sz, rc;
@@ -1555,7 +1555,12 @@ static int ntlm_authenticate(struct ksmbd_work *work,
 				return -ENOMEM;
 
 			chann->conn = conn;
-			xa_store(&sess->ksmbd_chann_list, (long)conn, chann, KSMBD_DEFAULT_GFP);
+			old = xa_store(&sess->ksmbd_chann_list, (long)conn, chann,
+					KSMBD_DEFAULT_GFP);
+			if (xa_is_err(old)) {
+				kfree(chann);
+				return xa_err(old);
+			}
 		}
 	}
 
-- 
2.39.5

[PATCH AUTOSEL 6.12 16/18] cifs: Fix and improve cifs_query_path_info() and cifs_query_file_info()

[Sasha Levin]

From: Pali Rohár <pali@kernel.org>

[ Upstream commit 1041c117a2c33cdffc4f695ac4b469e9124d24d5 ]

When CAP_NT_SMBS was not negotiated then do not issue CIFSSMBQPathInfo()
and CIFSSMBQFileInfo() commands. CIFSSMBQPathInfo() is not supported by
non-NT Win9x SMB server and CIFSSMBQFileInfo() returns from Win9x SMB
server bogus data in Attributes field (for example lot of files are marked
as reparse points, even Win9x does not support them and read-only bit is
not marked for read-only files). Correct information is returned by
CIFSFindFirst() or SMBQueryInformation() command.

So as a fallback in cifs_query_path_info() function use CIFSFindFirst()
with SMB_FIND_FILE_FULL_DIRECTORY_INFO level which is supported by both NT
and non-NT servers and as a last option use SMBQueryInformation() as it was
before.

And in function cifs_query_file_info() immediately returns -EOPNOTSUPP when
not communicating with NT server. Client then revalidate inode entry by the
cifs_query_path_info() call, which is working fine. So fstat() syscall on
already opened file will receive correct information.

Note that both fallback functions in non-UNICODE mode expands wildcards.
Therefore those fallback functions cannot be used on paths which contain
SMB wildcard characters (* ? " > <).

CIFSFindFirst() returns all 4 time attributes as opposite of
SMBQueryInformation() which returns only one.

With this change it is possible to query all 4 times attributes from Win9x
server and at the same time, client minimize sending of unsupported
commands to server.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/client/smb1ops.c | 103 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 95 insertions(+), 8 deletions(-)

diff --git a/fs/smb/client/smb1ops.c b/fs/smb/client/smb1ops.c
index 55cceb8229323..2f85272948b90 100644
--- a/fs/smb/client/smb1ops.c
+++ b/fs/smb/client/smb1ops.c
@@ -548,24 +548,104 @@ static int cifs_query_path_info(const unsigned int xid,
 				const char *full_path,
 				struct cifs_open_info_data *data)
 {
-	int rc;
+	int rc = -EOPNOTSUPP;
 	FILE_ALL_INFO fi = {};
+	struct cifs_search_info search_info = {};
+	bool non_unicode_wildcard = false;
 
 	data->reparse_point = false;
 	data->adjust_tz = false;
 
-	/* could do find first instead but this returns more info */
-	rc = CIFSSMBQPathInfo(xid, tcon, full_path, &fi, 0 /* not legacy */, cifs_sb->local_nls,
-			      cifs_remap(cifs_sb));
 	/*
-	 * BB optimize code so we do not make the above call when server claims
-	 * no NT SMB support and the above call failed at least once - set flag
-	 * in tcon or mount.
+	 * First try CIFSSMBQPathInfo() function which returns more info
+	 * (NumberOfLinks) than CIFSFindFirst() fallback function.
+	 * Some servers like Win9x do not support SMB_QUERY_FILE_ALL_INFO over
+	 * TRANS2_QUERY_PATH_INFORMATION, but supports it with filehandle over
+	 * TRANS2_QUERY_FILE_INFORMATION (function CIFSSMBQFileInfo(). But SMB
+	 * Open command on non-NT servers works only for files, does not work
+	 * for directories. And moreover Win9x SMB server returns bogus data in
+	 * SMB_QUERY_FILE_ALL_INFO Attributes field. So for non-NT servers,
+	 * do not even use CIFSSMBQPathInfo() or CIFSSMBQFileInfo() function.
+	 */
+	if (tcon->ses->capabilities & CAP_NT_SMBS)
+		rc = CIFSSMBQPathInfo(xid, tcon, full_path, &fi, 0 /* not legacy */,
+				      cifs_sb->local_nls, cifs_remap(cifs_sb));
+
+	/*
+	 * Non-UNICODE variant of fallback functions below expands wildcards,
+	 * so they cannot be used for querying paths with wildcard characters.
 	 */
-	if ((rc == -EOPNOTSUPP) || (rc == -EINVAL)) {
+	if (rc && !(tcon->ses->capabilities & CAP_UNICODE) && strpbrk(full_path, "*?\"><"))
+		non_unicode_wildcard = true;
+
+	/*
+	 * Then fallback to CIFSFindFirst() which works also with non-NT servers
+	 * but does not does not provide NumberOfLinks.
+	 */
+	if ((rc == -EOPNOTSUPP || rc == -EINVAL) &&
+	    !non_unicode_wildcard) {
+		if (!(tcon->ses->capabilities & tcon->ses->server->vals->cap_nt_find))
+			search_info.info_level = SMB_FIND_FILE_INFO_STANDARD;
+		else
+			search_info.info_level = SMB_FIND_FILE_FULL_DIRECTORY_INFO;
+		rc = CIFSFindFirst(xid, tcon, full_path, cifs_sb, NULL,
+				   CIFS_SEARCH_CLOSE_ALWAYS | CIFS_SEARCH_CLOSE_AT_END,
+				   &search_info, false);
+		if (rc == 0) {
+			if (!(tcon->ses->capabilities & tcon->ses->server->vals->cap_nt_find)) {
+				FIND_FILE_STANDARD_INFO *di;
+				int offset = tcon->ses->server->timeAdj;
+
+				di = (FIND_FILE_STANDARD_INFO *)search_info.srch_entries_start;
+				fi.CreationTime = cpu_to_le64(cifs_UnixTimeToNT(cnvrtDosUnixTm(
+						di->CreationDate, di->CreationTime, offset)));
+				fi.LastAccessTime = cpu_to_le64(cifs_UnixTimeToNT(cnvrtDosUnixTm(
+						di->LastAccessDate, di->LastAccessTime, offset)));
+				fi.LastWriteTime = cpu_to_le64(cifs_UnixTimeToNT(cnvrtDosUnixTm(
+						di->LastWriteDate, di->LastWriteTime, offset)));
+				fi.ChangeTime = fi.LastWriteTime;
+				fi.Attributes = cpu_to_le32(le16_to_cpu(di->Attributes));
+				fi.AllocationSize = cpu_to_le64(le32_to_cpu(di->AllocationSize));
+				fi.EndOfFile = cpu_to_le64(le32_to_cpu(di->DataSize));
+			} else {
+				FILE_FULL_DIRECTORY_INFO *di;
+
+				di = (FILE_FULL_DIRECTORY_INFO *)search_info.srch_entries_start;
+				fi.CreationTime = di->CreationTime;
+				fi.LastAccessTime = di->LastAccessTime;
+				fi.LastWriteTime = di->LastWriteTime;
+				fi.ChangeTime = di->ChangeTime;
+				fi.Attributes = di->ExtFileAttributes;
+				fi.AllocationSize = di->AllocationSize;
+				fi.EndOfFile = di->EndOfFile;
+				fi.EASize = di->EaSize;
+			}
+			fi.NumberOfLinks = cpu_to_le32(1);
+			fi.DeletePending = 0;
+			fi.Directory = !!(le32_to_cpu(fi.Attributes) & ATTR_DIRECTORY);
+			cifs_buf_release(search_info.ntwrk_buf_start);
+		} else if (!full_path[0]) {
+			/*
+			 * CIFSFindFirst() does not work on root path if the
+			 * root path was exported on the server from the top
+			 * level path (drive letter).
+			 */
+			rc = -EOPNOTSUPP;
+		}
+	}
+
+	/*
+	 * If everything failed then fallback to the legacy SMB command
+	 * SMB_COM_QUERY_INFORMATION which works with all servers, but
+	 * provide just few information.
+	 */
+	if ((rc == -EOPNOTSUPP || rc == -EINVAL) && !non_unicode_wildcard) {
 		rc = SMBQueryInformation(xid, tcon, full_path, &fi, cifs_sb->local_nls,
 					 cifs_remap(cifs_sb));
 		data->adjust_tz = true;
+	} else if ((rc == -EOPNOTSUPP || rc == -EINVAL) && non_unicode_wildcard) {
+		/* Path with non-UNICODE wildcard character cannot exist. */
+		rc = -ENOENT;
 	}
 
 	if (!rc) {
@@ -662,6 +742,13 @@ static int cifs_query_file_info(const unsigned int xid, struct cifs_tcon *tcon,
 	int rc;
 	FILE_ALL_INFO fi = {};
 
+	/*
+	 * CIFSSMBQFileInfo() for non-NT servers returns bogus data in
+	 * Attributes fields. So do not use this command for non-NT servers.
+	 */
+	if (!(tcon->ses->capabilities & CAP_NT_SMBS))
+		return -EOPNOTSUPP;
+
 	if (cfile->symlink_target) {
 		data->symlink_target = kstrdup(cfile->symlink_target, GFP_KERNEL);
 		if (!data->symlink_target)
-- 
2.39.5

[PATCH AUTOSEL 6.12 17/18] cifs: Fix changing times and read-only attr over SMB1 smb_set_file_info() function

[Sasha Levin]

From: Pali Rohár <pali@kernel.org>

[ 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>
---
 fs/smb/client/cifspdu.h   |   5 +-
 fs/smb/client/cifsproto.h |   4 ++
 fs/smb/client/cifssmb.c   |  57 +++++++++++++++++++
 fs/smb/client/smb1ops.c   | 112 +++++++++++++++++++++++++++++++++++---
 4 files changed, 166 insertions(+), 12 deletions(-)

diff --git a/fs/smb/client/cifspdu.h b/fs/smb/client/cifspdu.h
index ee78bb6741d62..28f8ca470770d 100644
--- a/fs/smb/client/cifspdu.h
+++ b/fs/smb/client/cifspdu.h
@@ -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;
diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h
index 90b7b30abfbd8..23a7d5a589ee7 100644
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -393,6 +393,10 @@ 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,
diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c
index e2a14e25da87c..8667f403a0ab6 100644
--- a/fs/smb/client/cifssmb.c
+++ b/fs/smb/client/cifssmb.c
@@ -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
diff --git a/fs/smb/client/smb1ops.c b/fs/smb/client/smb1ops.c
index 2f85272948b90..fe2a008c41428 100644
--- a/fs/smb/client/smb1ops.c
+++ b/fs/smb/client/smb1ops.c
@@ -919,6 +919,9 @@ 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;
@@ -926,20 +929,58 @@ 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);
@@ -960,8 +1001,45 @@ 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;
@@ -969,6 +1047,7 @@ 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);
@@ -979,6 +1058,21 @@ smb_set_file_info(struct inode *inode, const char *full_path,
 		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);
-- 
2.39.5