From: Chuck Lever <chuck.lever@xxxxxxxxxx>
De-duplicate the same functionality in several places by hoisting
the is_dot_dotdot() utility function into linux/fs.h.
Suggested-by: Amir Goldstein <amir73il@xxxxxxxxx>
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/crypto/fname.c | 8 +-------
fs/ecryptfs/crypto.c | 10 ----------
fs/exportfs/expfs.c | 4 +---
fs/f2fs/f2fs.h | 11 -----------
fs/namei.c | 6 ++----
include/linux/fs.h | 13 +++++++++++++
6 files changed, 17 insertions(+), 35 deletions(-)
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 7b3fc189593a..0ad52fbe51c9 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -74,13 +74,7 @@ struct fscrypt_nokey_name {
static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
{
- if (str->len == 1 && str->name[0] == '.')
- return true;
-
- if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
- return true;
-
- return false;
+ return is_dot_dotdot(str->name, str->len);
}
/**
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 03bd55069d86..2fe0f3af1a08 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1949,16 +1949,6 @@ int ecryptfs_encrypt_and_encode_filename(
return rc;
}
-static bool is_dot_dotdot(const char *name, size_t name_size)
-{
- if (name_size == 1 && name[0] == '.')
- return true;
- else if (name_size == 2 && name[0] == '.' && name[1] == '.')
- return true;
-
- return false;
-}
-
/**
* ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
* @plaintext_name: The plaintext name
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 84af58eaf2ca..07ea3d62b298 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -255,9 +255,7 @@ static bool filldir_one(struct dir_context *ctx, const char *name, int len,
container_of(ctx, struct getdents_callback, ctx);
buf->sequence++;
- /* Ignore the '.' and '..' entries */
- if ((len > 2 || name[0] != '.' || (len == 2 && name[1] != '.')) &&
- buf->ino == ino && len <= NAME_MAX) {
+ if (buf->ino == ino && len <= NAME_MAX && !is_dot_dotdot(name, len)) {
memcpy(buf->name, name, len);
buf->name[len] = '\0';
buf->found = 1;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9043cedfa12b..322a3b8a3533 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3368,17 +3368,6 @@ static inline bool f2fs_cp_error(struct f2fs_sb_info *sbi)
return is_set_ckpt_flags(sbi, CP_ERROR_FLAG);
}
-static inline bool is_dot_dotdot(const u8 *name, size_t len)
-{
- if (len == 1 && name[0] == '.')
- return true;
-
- if (len == 2 && name[0] == '.' && name[1] == '.')
- return true;
-
- return false;
-}
-
static inline void *f2fs_kmalloc(struct f2fs_sb_info *sbi,
size_t size, gfp_t flags)
{
diff --git a/fs/namei.c b/fs/namei.c
index 71c13b2990b4..2386a70667fa 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2667,10 +2667,8 @@ static int lookup_one_common(struct mnt_idmap *idmap,
if (!len)
return -EACCES;
- if (unlikely(name[0] == '.')) {
- if (len < 2 || (len == 2 && name[1] == '.'))
- return -EACCES;
- }
+ if (is_dot_dotdot(name, len))
+ return -EACCES;
while (len--) {
unsigned int c = *(const unsigned char *)name++;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 98b7a7a8c42e..53dd58a907e0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2846,6 +2846,19 @@ extern bool path_is_under(const struct path *, const struct path *);
extern char *file_path(struct file *, char *, int);
+/**
+ * is_dot_dotdot - returns true only if @name is "." or ".."
+ * @name: file name to check
+ * @len: length of file name, in bytes
+ *
+ * Coded for efficiency.
+ */
+static inline bool is_dot_dotdot(const char *name, size_t len)
+{
+ return len && unlikely(name[0] == '.') &&
+ (len < 2 || (len == 2 && name[1] == '.'));
+}
+
#include <linux/err.h>
/* needed for stackable file system support */
