Hello ZhangPeng,
The patch fb6b59b5a2d6: "fs/ntfs3: Fix null-ptr-deref on inode->i_op
in ntfs_lookup()" from Nov 25, 2022, leads to the following Smatch
static checker warning:
fs/ntfs3/namei.c:96 ntfs_lookup()
error: potential NULL/IS_ERR bug 'inode'
fs/ntfs3/namei.c
67 static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *dentry,
68 u32 flags)
69 {
70 struct ntfs_inode *ni = ntfs_i(dir);
71 struct cpu_str *uni = __getname();
72 struct inode *inode;
73 int err;
74
75 if (!uni)
76 inode = ERR_PTR(-ENOMEM);
77 else {
78 err = ntfs_nls_to_utf16(ni->mi.sbi, dentry->d_name.name,
79 dentry->d_name.len, uni, NTFS_NAME_LEN,
80 UTF16_HOST_ENDIAN);
81 if (err < 0)
82 inode = ERR_PTR(err);
83 else {
84 ni_lock(ni);
85 inode = dir_search_u(dir, uni, NULL);
The issue for Smatch is that dir_search_u() returns NULL if the file
is not found, or an error if there is an error, or a valid pointer.
86 ni_unlock(ni);
87 }
88 __putname(uni);
89 }
90
91 /*
92 * Check for a null pointer
93 * If the MFT record of ntfs inode is not a base record, inode->i_op can be NULL.
94 * This causes null pointer dereference in d_splice_alias().
95 */
--> 96 if (!IS_ERR(inode) && inode->i_op == NULL) {
^^^^^^^
Potential NULL dereference. Seems easy to hit too.
97 iput(inode);
98 inode = ERR_PTR(-EINVAL);
99 }
100
101 return d_splice_alias(inode, dentry);
102 }
regards,
dan carpenter
