smb/client: preserve open info type across compound queries

contains_posix_file_info describes the metadata stored in the
fi/posix_fi union. GET_REPARSE and QUERY_WSL_EA do not update that
union, so clearing the flag while processing those responses can make
POSIX metadata look like FILE_ALL_INFORMATION.

Set the flag when CREATE or a validated query response actually
populates the union, and leave it unchanged for auxiliary compound
operations. This also avoids changing the type when a query fails
before copying any metadata.

The issue can be reproduced against a Samba server with SMB3 UNIX
extensions enabled:

  mount -t cifs //<server>/<share> /mnt/cifs \
        -o vers=3.1.1,posix,reparse=nfs,actimeo=0
  mkfifo /mnt/cifs/test-fifo
  umount /mnt/cifs
  mount -t cifs //<server>/<share> /mnt/cifs \
        -o vers=3.1.1,posix,reparse=nfs,actimeo=0
  stat -c '%F %s' /mnt/cifs/test-fifo

Before this change, stat reports "fifo 1024" although the server-side
EOF is zero. After this change, it reports "fifo 0".

Fixes: 9df23801c83d ("smb311: failure to open files of length 1040 when mounting with SMB3.1.1 POSIX extensions")
Signed-off-by: Ze Tan <tanze@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>

2 files changed, 6 insertions, 4 deletions

diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index d4ae8a5ad463..058b05f7a3e5 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -574,6 +574,7 @@ finished:
 		idata->fi.Attributes = create_rsp->FileAttributes;
 		idata->fi.AllocationSize = create_rsp->AllocationSize;
 		idata->fi.EndOfFile = create_rsp->EndofFile;
+		idata->contains_posix_file_info = false;
 		if (le32_to_cpu(idata->fi.NumberOfLinks) == 0)
 			idata->fi.NumberOfLinks = cpu_to_le32(1); /* dummy value */
 		idata->unknown_nlink = true;
@@ -597,7 +598,6 @@ finished:
 		switch (cmds[i]) {
 		case SMB2_OP_QUERY_INFO:
 			idata = in_iov[i].iov_base;
-			idata->contains_posix_file_info = false;
 			if (rc == 0 && cfile && cfile->symlink_target) {
 				idata->symlink_target = kstrdup(cfile->symlink_target, GFP_KERNEL);
 				if (!idata->symlink_target)
@@ -610,6 +610,8 @@ finished:
 					le16_to_cpu(qi_rsp->OutputBufferOffset),
 					le32_to_cpu(qi_rsp->OutputBufferLength),
 					&rsp_iov[i + 1], sizeof(idata->fi), (char *)&idata->fi);
+				if (!rc)
+					idata->contains_posix_file_info = false;
 			}
 			SMB2_query_info_free(&rqst[num_rqst++]);
 			if (rc)
@@ -621,7 +623,6 @@ finished:
 			break;
 		case SMB2_OP_POSIX_QUERY_INFO:
 			idata = in_iov[i].iov_base;
-			idata->contains_posix_file_info = true;
 			if (rc == 0 && cfile && cfile->symlink_target) {
 				idata->symlink_target = kstrdup(cfile->symlink_target, GFP_KERNEL);
 				if (!idata->symlink_target)
@@ -635,6 +636,8 @@ finished:
 					le32_to_cpu(qi_rsp->OutputBufferLength),
 					&rsp_iov[i + 1], sizeof(idata->posix_fi) /* add SIDs */,
 					(char *)&idata->posix_fi);
+				if (!rc)
+					idata->contains_posix_file_info = true;
 			}
 			if (rc == 0)
 				rc = parse_posix_sids(idata, &rsp_iov[i + 1]);
@@ -706,7 +709,6 @@ finished:
 				idata = in_iov[i].iov_base;
 				idata->reparse.io.iov = *iov;
 				idata->reparse.io.buftype = resp_buftype[i + 1];
-				idata->contains_posix_file_info = false; /* BB VERIFY */
 				rbuf = reparse_buf_ptr(iov);
 				if (IS_ERR(rbuf)) {
 					rc = PTR_ERR(rbuf);
@@ -728,7 +730,6 @@ finished:
 		case SMB2_OP_QUERY_WSL_EA:
 			if (!rc) {
 				idata = in_iov[i].iov_base;
-				idata->contains_posix_file_info = false;
 				qi_rsp = rsp_iov[i + 1].iov_base;
 				data[0] = (u8 *)qi_rsp + le16_to_cpu(qi_rsp->OutputBufferOffset);
 				size[0] = le32_to_cpu(qi_rsp->OutputBufferLength);
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index d207591cc889..dea05aeb53a1 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -3372,6 +3372,7 @@ replay_again:
 #endif /* CIFS_DEBUG2 */
 
 	if (file_info) {
+		buf->contains_posix_file_info = false;
 		file_info->CreationTime = rsp->CreationTime;
 		file_info->LastAccessTime = rsp->LastAccessTime;
 		file_info->LastWriteTime = rsp->LastWriteTime;