> On Jan 5, 2024, at 2:36 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote:
>
> On Thu, Jan 4, 2024 at 10:55 PM Chuck Lever <cel@xxxxxxxxxx> wrote:
>>
>> 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>
>
> Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
>
>> ---
>> 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] == '.'));
>> +}
>> +
>
> Looking back at the version that I suggested, (len < 2
> here is silly and should be (len == 1 || ...
>
> But let's wait for inputs from other developers on this helper,
> especially Al.
Al, any comments on this clean-up ?
--
Chuck Lever
