[PATCH v2 5/5] smb: client: fix reparse point file type corruption

[Paulo Alcantara <pc@manguebit.org>]

wsl_to_fattr() and posix_reparse_to_fattr() set the file type from
reparse point tags (e.g. fattr->cf_mode |= S_IFCHR).  When cf_mode
already has S_IFMT bits set by the caller, this corrupts the file
type.

For example, smb311_posix_info_to_fattr() sets cf_mode via
wire_mode_to_posix() which includes S_IFREG, then calls
cifs_reparse_point_to_fattr().  If the reparse tag indicates a
character device, the result is S_IFREG | S_IFCHR = S_IFLNK,
incorrectly turning the inode into a symlink.

Fix both functions by clearing the S_IFMT bits before the switch
statement, so the reparse point tag can set the correct file type
without interference from previously set bits.

Closes: https://sashiko.dev/#/patchset/20260906172005.627163-1-pc%40manguebit.org
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
---
 fs/smb/client/reparse.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c
index 10ef82d46d86..773ad2e21b47 100644
--- a/fs/smb/client/reparse.c
+++ b/fs/smb/client/reparse.c
@@ -1146,6 +1146,7 @@ static bool wsl_to_fattr(struct cifs_open_info_data *data,
 	fattr->cf_uid = cifs_sb->ctx->linux_uid;
 	fattr->cf_gid = cifs_sb->ctx->linux_gid;
 
+	fattr->cf_mode &= ~S_IFMT;
 	switch (tag) {
 	case IO_REPARSE_TAG_LX_SYMLINK:
 		fattr->cf_mode |= S_IFLNK;
@@ -1234,6 +1235,7 @@ static bool posix_reparse_to_fattr(struct cifs_sb_info *cifs_sb,
 		return false;
 	}
 
+	fattr->cf_mode &= ~S_IFMT;
 	switch (le64_to_cpu(buf->InodeType)) {
 	case NFS_SPECFILE_CHR:
 		if (le16_to_cpu(buf->ReparseDataLength) != sizeof(buf->InodeType) + 8) {
-- 
2.55.0