diff mbox series

[14/20] fuse_dentry_revalidate(): use stable parent inode and name passed by caller

Message ID 20250110024303.4157645-14-viro@zeniv.linux.org.uk (mailing list archive)
State New
Headers show
Series [01/20] make sure that DNAME_INLINE_LEN is a multiple of word size | expand

Commit Message

Al Viro Jan. 10, 2025, 2:42 a.m. UTC 
No need to mess with dget_parent() for the former; for the latter we really should
not rely upon ->d_name.name remaining stable - it's a real-life UAF.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/fuse/dir.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index d9e9f26917eb..7e93a8470c36 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -196,7 +196,6 @@  static int fuse_dentry_revalidate(struct inode *dir, const struct qstr *name,
 				  struct dentry *entry, unsigned int flags)
 {
 	struct inode *inode;
-	struct dentry *parent;
 	struct fuse_mount *fm;
 	struct fuse_inode *fi;
 	int ret;
@@ -228,11 +227,9 @@  static int fuse_dentry_revalidate(struct inode *dir, const struct qstr *name,
 
 		attr_version = fuse_get_attr_version(fm->fc);
 
-		parent = dget_parent(entry);
-		fuse_lookup_init(fm->fc, &args, get_node_id(d_inode(parent)),
-				 &entry->d_name, &outarg);
+		fuse_lookup_init(fm->fc, &args, get_node_id(dir),
+				 name, &outarg);
 		ret = fuse_simple_request(fm, &args);
-		dput(parent);
 		/* Zero nodeid is same as -ENOENT */
 		if (!ret && !outarg.nodeid)
 			ret = -ENOENT;
@@ -266,9 +263,7 @@  static int fuse_dentry_revalidate(struct inode *dir, const struct qstr *name,
 			if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
 				return -ECHILD;
 		} else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
-			parent = dget_parent(entry);
-			fuse_advise_use_readdirplus(d_inode(parent));
-			dput(parent);
+			fuse_advise_use_readdirplus(dir);
 		}
 	}
 	ret = 1;