[PATCH AUTOSEL 5.15 09/28] fs/ntfs3: Fix directory element type detection

From: Sasha Levin
Date: Sun Oct 29 2023 - 19:57:51 EST


From: Gabriel Marcano <gabemarcano@xxxxxxxxx>

[ Upstream commit 85a4780dc96ed9dd643bbadf236552b3320fae26 ]

Calling stat() from userspace correctly identified junctions in an NTFS
partition as symlinks, but using readdir() and iterating through the
directory containing the same junction did not identify the junction
as a symlink.

When emitting directory contents, check FILE_ATTRIBUTE_REPARSE_POINT
attribute to detect junctions and report them as links.

Signed-off-by: Gabriel Marcano <gabemarcano@xxxxxxxxx>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/ntfs3/dir.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/ntfs3/dir.c b/fs/ntfs3/dir.c
index fb438d6040409..d4d9f4ffb6d9a 100644
--- a/fs/ntfs3/dir.c
+++ b/fs/ntfs3/dir.c
@@ -309,7 +309,11 @@ static inline int ntfs_filldir(struct ntfs_sb_info *sbi, struct ntfs_inode *ni,
return 0;
}

- dt_type = (fname->dup.fa & FILE_ATTRIBUTE_DIRECTORY) ? DT_DIR : DT_REG;
+ /* NTFS: symlinks are "dir + reparse" or "file + reparse" */
+ if (fname->dup.fa & FILE_ATTRIBUTE_REPARSE_POINT)
+ dt_type = DT_LNK;
+ else
+ dt_type = (fname->dup.fa & FILE_ATTRIBUTE_DIRECTORY) ? DT_DIR : DT_REG;

return !dir_emit(ctx, (s8 *)name, name_len, ino, dt_type);
}
--
2.42.0