[PATCH v2] fs: Fix uninitialized value issue in from_kuid and from_kgid

From: Alessandro Zanni
Date: Thu Oct 17 2024 - 08:06:21 EST


ocfs2_setattr() uses attr->ia_mode, attr->ia_uid and attr->ia_gid in
a trace point even though ATTR_MODE, ATTR_UID and ATTR_GID aren't set.

Initialize all fields of newattrs to avoid uninitialized variables, by
checking if ATTR_MODE, ATTR_UID, ATTR_GID are initialized, otherwise 0.

Reported-by: syzbot+6c55f725d1bdc8c52058@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=6c55f725d1bdc8c52058
Signed-off-by: Alessandro Zanni <alessandro.zanni87@xxxxxxxxx>
---

Notes:
v2: fix ocfs2_setattr to avoid similar issues; improved commit description

fs/ocfs2/file.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index ad131a2fc58e..58887456e3c5 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1129,9 +1129,12 @@ int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
trace_ocfs2_setattr(inode, dentry,
(unsigned long long)OCFS2_I(inode)->ip_blkno,
dentry->d_name.len, dentry->d_name.name,
- attr->ia_valid, attr->ia_mode,
- from_kuid(&init_user_ns, attr->ia_uid),
- from_kgid(&init_user_ns, attr->ia_gid));
+ attr->ia_valid,
+ attr->ia_valid & ATTR_MODE ? attr->ia_mode : 0,
+ attr->ia_valid & ATTR_UID ?
+ from_kuid(&init_user_ns, attr->ia_uid) : 0,
+ attr->ia_valid & ATTR_GID ?
+ from_kgid(&init_user_ns, attr->ia_gid) : 0);

/* ensuring we don't even attempt to truncate a symlink */
if (S_ISLNK(inode->i_mode))
--
2.43.0