Several filename crypto functions: fname_decrypt(),
fscrypt_fname_disk_to_usr(), and fscrypt_fname_usr_to_disk(), returned
the output length on success or -errno on failure. However, the output
length was redundant with the value written to 'oname->len'. It is also
potentially error-prone to make callers have to check for '< 0' instead
of '!= 0'.
Therefore, make these functions return 0 instead of a length, and make
the callers who cared about the return value being a length use
'oname->len' instead.
This change also fixes the inconsistency of fname_encrypt() actually
already returning 0 on success, not a length like the other filename
crypto functions and as documented in its function comment.
Signed-off-by: Eric Biggers <[email protected]>
---
fs/crypto/fname.c | 52 ++++++++++++++++++++++++++++++----------------------
fs/ext4/dir.c | 5 +++--
fs/ext4/symlink.c | 5 ++---
fs/f2fs/namei.c | 4 ++--
4 files changed, 37 insertions(+), 29 deletions(-)
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 6bbc3b1..49fd564 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -35,11 +35,11 @@ static void fname_crypt_complete(struct crypto_async_request *req, int res)
}
/**
- * fname_encrypt() -
+ * fname_encrypt() - encrypt a filename
*
- * This function encrypts the input filename, and returns the length of the
- * ciphertext. Errors are returned as negative numbers. We trust the caller to
- * allocate sufficient memory to oname string.
+ * The caller must have allocated sufficient memory for the @oname string.
+ *
+ * Return: 0 on success, -errno on failure
*/
static int fname_encrypt(struct inode *inode,
const struct qstr *iname, struct fscrypt_str *oname)
@@ -105,20 +105,22 @@ static int fname_encrypt(struct inode *inode,
}
kfree(alloc_buf);
skcipher_request_free(req);
- if (res < 0)
+ if (res < 0) {
printk_ratelimited(KERN_ERR
"%s: Error (error code %d)\n", __func__, res);
+ return res;
+ }
oname->len = ciphertext_len;
- return res;
+ return 0;
}
-/*
- * fname_decrypt()
- * This function decrypts the input filename, and returns
- * the length of the plaintext.
- * Errors are returned as negative numbers.
- * We trust the caller to allocate sufficient memory to oname string.
+/**
+ * fname_decrypt() - decrypt a filename
+ *
+ * The caller must have allocated sufficient memory for the @oname string.
+ *
+ * Return: 0 on success, -errno on failure
*/
static int fname_decrypt(struct inode *inode,
const struct fscrypt_str *iname,
@@ -168,7 +170,7 @@ static int fname_decrypt(struct inode *inode,
}
oname->len = strnlen(oname->name, iname->len);
- return oname->len;
+ return 0;
}
static const char *lookup_table =
@@ -279,6 +281,10 @@ EXPORT_SYMBOL(fscrypt_fname_free_buffer);
/**
* fscrypt_fname_disk_to_usr() - converts a filename from disk space to user
* space
+ *
+ * The caller must have allocated sufficient memory for the @oname string.
+ *
+ * Return: 0 on success, -errno on failure
*/
int fscrypt_fname_disk_to_usr(struct inode *inode,
u32 hash, u32 minor_hash,
@@ -287,13 +293,12 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
{
const struct qstr qname = FSTR_TO_QSTR(iname);
char buf[24];
- int ret;
if (fscrypt_is_dot_dotdot(&qname)) {
oname->name[0] = '.';
oname->name[iname->len - 1] = '.';
oname->len = iname->len;
- return oname->len;
+ return 0;
}
if (iname->len < FS_CRYPTO_BLOCK_SIZE)
@@ -303,9 +308,9 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
return fname_decrypt(inode, iname, oname);
if (iname->len <= FS_FNAME_CRYPTO_DIGEST_SIZE) {
- ret = digest_encode(iname->name, iname->len, oname->name);
- oname->len = ret;
- return ret;
+ oname->len = digest_encode(iname->name, iname->len,
+ oname->name);
+ return 0;
}
if (hash) {
memcpy(buf, &hash, 4);
@@ -315,15 +320,18 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
}
memcpy(buf + 8, iname->name + iname->len - 16, 16);
oname->name[0] = '_';
- ret = digest_encode(buf, 24, oname->name + 1);
- oname->len = ret + 1;
- return ret + 1;
+ oname->len = 1 + digest_encode(buf, 24, oname->name + 1);
+ return 0;
}
EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
/**
* fscrypt_fname_usr_to_disk() - converts a filename from user space to disk
* space
+ *
+ * The caller must have allocated sufficient memory for the @oname string.
+ *
+ * Return: 0 on success, -errno on failure
*/
int fscrypt_fname_usr_to_disk(struct inode *inode,
const struct qstr *iname,
@@ -333,7 +341,7 @@ int fscrypt_fname_usr_to_disk(struct inode *inode,
oname->name[0] = '.';
oname->name[iname->len - 1] = '.';
oname->len = iname->len;
- return oname->len;
+ return 0;
}
if (inode->i_crypt_info)
return fname_encrypt(inode, iname, oname);
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 67415e0..4d4b910 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -260,11 +260,12 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
/* Directory is encrypted */
err = fscrypt_fname_disk_to_usr(inode,
0, 0, &de_name, &fstr);
+ de_name = fstr;
fstr.len = save_len;
- if (err < 0)
+ if (err)
goto errout;
if (!dir_emit(ctx,
- fstr.name, err,
+ de_name.name, de_name.len,
le32_to_cpu(de->inode),
get_dtype(sb, de->file_type)))
goto done;
diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 4d83d9e..55aaf30 100644
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -67,14 +67,13 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
goto errout;
res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
- if (res < 0)
+ if (res)
goto errout;
paddr = pstr.name;
/* Null-terminate the name */
- if (res <= pstr.len)
- paddr[res] = '\0';
+ paddr[pstr.len] = '\0';
if (cpage)
put_page(cpage);
set_delayed_call(done, kfree_link, paddr);
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 73fa356..a5468c2 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -1048,7 +1048,7 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
goto errout;
res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
- if (res < 0)
+ if (res)
goto errout;
/* this is broken symlink case */
@@ -1060,7 +1060,7 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
paddr = pstr.name;
/* Null-terminate the name */
- paddr[res] = '\0';
+ paddr[pstr.len] = '\0';
put_page(cpage);
set_delayed_call(done, kfree_link, paddr);
--
2.8.0.rc3.226.g39d4020
Hi Eric,
On Wed, Sep 14, 2016 at 04:00:45PM -0700, Eric Biggers wrote:
> Several filename crypto functions: fname_decrypt(),
> fscrypt_fname_disk_to_usr(), and fscrypt_fname_usr_to_disk(), returned
> the output length on success or -errno on failure. However, the output
> length was redundant with the value written to 'oname->len'. It is also
> potentially error-prone to make callers have to check for '< 0' instead
> of '!= 0'.
At a glance, you missed some places like
- fscrypt_fname_usr_to_disk() in ext4_symlink() and f2fs_symlink()
- fscrypt_fname_disk_to_usr() in dx_show_leaf() and f2fs_fill_dentries()
Thanks,
> Therefore, make these functions return 0 instead of a length, and make
> the callers who cared about the return value being a length use
> 'oname->len' instead.
>
> This change also fixes the inconsistency of fname_encrypt() actually
> already returning 0 on success, not a length like the other filename
> crypto functions and as documented in its function comment.
>
> Signed-off-by: Eric Biggers <[email protected]>
> ---
> fs/crypto/fname.c | 52 ++++++++++++++++++++++++++++++----------------------
> fs/ext4/dir.c | 5 +++--
> fs/ext4/symlink.c | 5 ++---
> fs/f2fs/namei.c | 4 ++--
> 4 files changed, 37 insertions(+), 29 deletions(-)
>
> diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
> index 6bbc3b1..49fd564 100644
> --- a/fs/crypto/fname.c
> +++ b/fs/crypto/fname.c
> @@ -35,11 +35,11 @@ static void fname_crypt_complete(struct crypto_async_request *req, int res)
> }
>
> /**
> - * fname_encrypt() -
> + * fname_encrypt() - encrypt a filename
> *
> - * This function encrypts the input filename, and returns the length of the
> - * ciphertext. Errors are returned as negative numbers. We trust the caller to
> - * allocate sufficient memory to oname string.
> + * The caller must have allocated sufficient memory for the @oname string.
> + *
> + * Return: 0 on success, -errno on failure
> */
> static int fname_encrypt(struct inode *inode,
> const struct qstr *iname, struct fscrypt_str *oname)
> @@ -105,20 +105,22 @@ static int fname_encrypt(struct inode *inode,
> }
> kfree(alloc_buf);
> skcipher_request_free(req);
> - if (res < 0)
> + if (res < 0) {
> printk_ratelimited(KERN_ERR
> "%s: Error (error code %d)\n", __func__, res);
> + return res;
> + }
>
> oname->len = ciphertext_len;
> - return res;
> + return 0;
> }
>
> -/*
> - * fname_decrypt()
> - * This function decrypts the input filename, and returns
> - * the length of the plaintext.
> - * Errors are returned as negative numbers.
> - * We trust the caller to allocate sufficient memory to oname string.
> +/**
> + * fname_decrypt() - decrypt a filename
> + *
> + * The caller must have allocated sufficient memory for the @oname string.
> + *
> + * Return: 0 on success, -errno on failure
> */
> static int fname_decrypt(struct inode *inode,
> const struct fscrypt_str *iname,
> @@ -168,7 +170,7 @@ static int fname_decrypt(struct inode *inode,
> }
>
> oname->len = strnlen(oname->name, iname->len);
> - return oname->len;
> + return 0;
> }
>
> static const char *lookup_table =
> @@ -279,6 +281,10 @@ EXPORT_SYMBOL(fscrypt_fname_free_buffer);
> /**
> * fscrypt_fname_disk_to_usr() - converts a filename from disk space to user
> * space
> + *
> + * The caller must have allocated sufficient memory for the @oname string.
> + *
> + * Return: 0 on success, -errno on failure
> */
> int fscrypt_fname_disk_to_usr(struct inode *inode,
> u32 hash, u32 minor_hash,
> @@ -287,13 +293,12 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
> {
> const struct qstr qname = FSTR_TO_QSTR(iname);
> char buf[24];
> - int ret;
>
> if (fscrypt_is_dot_dotdot(&qname)) {
> oname->name[0] = '.';
> oname->name[iname->len - 1] = '.';
> oname->len = iname->len;
> - return oname->len;
> + return 0;
> }
>
> if (iname->len < FS_CRYPTO_BLOCK_SIZE)
> @@ -303,9 +308,9 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
> return fname_decrypt(inode, iname, oname);
>
> if (iname->len <= FS_FNAME_CRYPTO_DIGEST_SIZE) {
> - ret = digest_encode(iname->name, iname->len, oname->name);
> - oname->len = ret;
> - return ret;
> + oname->len = digest_encode(iname->name, iname->len,
> + oname->name);
> + return 0;
> }
> if (hash) {
> memcpy(buf, &hash, 4);
> @@ -315,15 +320,18 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
> }
> memcpy(buf + 8, iname->name + iname->len - 16, 16);
> oname->name[0] = '_';
> - ret = digest_encode(buf, 24, oname->name + 1);
> - oname->len = ret + 1;
> - return ret + 1;
> + oname->len = 1 + digest_encode(buf, 24, oname->name + 1);
> + return 0;
> }
> EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
>
> /**
> * fscrypt_fname_usr_to_disk() - converts a filename from user space to disk
> * space
> + *
> + * The caller must have allocated sufficient memory for the @oname string.
> + *
> + * Return: 0 on success, -errno on failure
> */
> int fscrypt_fname_usr_to_disk(struct inode *inode,
> const struct qstr *iname,
> @@ -333,7 +341,7 @@ int fscrypt_fname_usr_to_disk(struct inode *inode,
> oname->name[0] = '.';
> oname->name[iname->len - 1] = '.';
> oname->len = iname->len;
> - return oname->len;
> + return 0;
> }
> if (inode->i_crypt_info)
> return fname_encrypt(inode, iname, oname);
> diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
> index 67415e0..4d4b910 100644
> --- a/fs/ext4/dir.c
> +++ b/fs/ext4/dir.c
> @@ -260,11 +260,12 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
> /* Directory is encrypted */
> err = fscrypt_fname_disk_to_usr(inode,
> 0, 0, &de_name, &fstr);
> + de_name = fstr;
> fstr.len = save_len;
> - if (err < 0)
> + if (err)
> goto errout;
> if (!dir_emit(ctx,
> - fstr.name, err,
> + de_name.name, de_name.len,
> le32_to_cpu(de->inode),
> get_dtype(sb, de->file_type)))
> goto done;
> diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
> index 4d83d9e..55aaf30 100644
> --- a/fs/ext4/symlink.c
> +++ b/fs/ext4/symlink.c
> @@ -67,14 +67,13 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
> goto errout;
>
> res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
> - if (res < 0)
> + if (res)
> goto errout;
>
> paddr = pstr.name;
>
> /* Null-terminate the name */
> - if (res <= pstr.len)
> - paddr[res] = '\0';
> + paddr[pstr.len] = '\0';
> if (cpage)
> put_page(cpage);
> set_delayed_call(done, kfree_link, paddr);
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index 73fa356..a5468c2 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -1048,7 +1048,7 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
> goto errout;
>
> res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
> - if (res < 0)
> + if (res)
> goto errout;
>
> /* this is broken symlink case */
> @@ -1060,7 +1060,7 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
> paddr = pstr.name;
>
> /* Null-terminate the name */
> - paddr[res] = '\0';
> + paddr[pstr.len] = '\0';
>
> put_page(cpage);
> set_delayed_call(done, kfree_link, paddr);
> --
> 2.8.0.rc3.226.g39d4020
On Wed, Sep 14, 2016 at 05:10:21PM -0700, Jaegeuk Kim wrote:
> Hi Eric,
>
> On Wed, Sep 14, 2016 at 04:00:45PM -0700, Eric Biggers wrote:
> > Several filename crypto functions: fname_decrypt(),
> > fscrypt_fname_disk_to_usr(), and fscrypt_fname_usr_to_disk(), returned
> > the output length on success or -errno on failure. However, the output
> > length was redundant with the value written to 'oname->len'. It is also
> > potentially error-prone to make callers have to check for '< 0' instead
> > of '!= 0'.
>
> At a glance, you missed some places like
> - fscrypt_fname_usr_to_disk() in ext4_symlink() and f2fs_symlink()
> - fscrypt_fname_disk_to_usr() in dx_show_leaf() and f2fs_fill_dentries()
>
Those callers don't have to be updated because they only check for an error
value --- they don't use the return value as a length. I did check all the
callers of fscrypt_fname_{usr_to_disk,disk_to_usr()}, and only the three I
update in the patch used the return value as a length.
Eric
On Sep 14, 2016, at 5:00 PM, Eric Biggers <[email protected]> wrote:
>
> Several filename crypto functions: fname_decrypt(),
> fscrypt_fname_disk_to_usr(), and fscrypt_fname_usr_to_disk(), returned
> the output length on success or -errno on failure. However, the output
> length was redundant with the value written to 'oname->len'. It is also
> potentially error-prone to make callers have to check for '< 0' instead
> of '!= 0'.
>
> Therefore, make these functions return 0 instead of a length, and make
> the callers who cared about the return value being a length use
> 'oname->len' instead.
>
> This change also fixes the inconsistency of fname_encrypt() actually
> already returning 0 on success, not a length like the other filename
> crypto functions and as documented in its function comment.
>
> Signed-off-by: Eric Biggers <[email protected]>
Reviewed-by: Andreas Dilger <[email protected]>
> ---
> fs/crypto/fname.c | 52 ++++++++++++++++++++++++++++++----------------------
> fs/ext4/dir.c | 5 +++--
> fs/ext4/symlink.c | 5 ++---
> fs/f2fs/namei.c | 4 ++--
> 4 files changed, 37 insertions(+), 29 deletions(-)
>
> diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
> index 6bbc3b1..49fd564 100644
> --- a/fs/crypto/fname.c
> +++ b/fs/crypto/fname.c
> @@ -35,11 +35,11 @@ static void fname_crypt_complete(struct crypto_async_request *req, int res)
> }
>
> /**
> - * fname_encrypt() -
> + * fname_encrypt() - encrypt a filename
> *
> - * This function encrypts the input filename, and returns the length of the
> - * ciphertext. Errors are returned as negative numbers. We trust the caller to
> - * allocate sufficient memory to oname string.
> + * The caller must have allocated sufficient memory for the @oname string.
> + *
> + * Return: 0 on success, -errno on failure
> */
> static int fname_encrypt(struct inode *inode,
> const struct qstr *iname, struct fscrypt_str *oname)
> @@ -105,20 +105,22 @@ static int fname_encrypt(struct inode *inode,
> }
> kfree(alloc_buf);
> skcipher_request_free(req);
> - if (res < 0)
> + if (res < 0) {
> printk_ratelimited(KERN_ERR
> "%s: Error (error code %d)\n", __func__, res);
> + return res;
> + }
>
> oname->len = ciphertext_len;
> - return res;
> + return 0;
> }
>
> -/*
> - * fname_decrypt()
> - * This function decrypts the input filename, and returns
> - * the length of the plaintext.
> - * Errors are returned as negative numbers.
> - * We trust the caller to allocate sufficient memory to oname string.
> +/**
> + * fname_decrypt() - decrypt a filename
> + *
> + * The caller must have allocated sufficient memory for the @oname string.
> + *
> + * Return: 0 on success, -errno on failure
> */
> static int fname_decrypt(struct inode *inode,
> const struct fscrypt_str *iname,
> @@ -168,7 +170,7 @@ static int fname_decrypt(struct inode *inode,
> }
>
> oname->len = strnlen(oname->name, iname->len);
> - return oname->len;
> + return 0;
> }
>
> static const char *lookup_table =
> @@ -279,6 +281,10 @@ EXPORT_SYMBOL(fscrypt_fname_free_buffer);
> /**
> * fscrypt_fname_disk_to_usr() - converts a filename from disk space to user
> * space
> + *
> + * The caller must have allocated sufficient memory for the @oname string.
> + *
> + * Return: 0 on success, -errno on failure
> */
> int fscrypt_fname_disk_to_usr(struct inode *inode,
> u32 hash, u32 minor_hash,
> @@ -287,13 +293,12 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
> {
> const struct qstr qname = FSTR_TO_QSTR(iname);
> char buf[24];
> - int ret;
>
> if (fscrypt_is_dot_dotdot(&qname)) {
> oname->name[0] = '.';
> oname->name[iname->len - 1] = '.';
> oname->len = iname->len;
> - return oname->len;
> + return 0;
> }
>
> if (iname->len < FS_CRYPTO_BLOCK_SIZE)
> @@ -303,9 +308,9 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
> return fname_decrypt(inode, iname, oname);
>
> if (iname->len <= FS_FNAME_CRYPTO_DIGEST_SIZE) {
> - ret = digest_encode(iname->name, iname->len, oname->name);
> - oname->len = ret;
> - return ret;
> + oname->len = digest_encode(iname->name, iname->len,
> + oname->name);
> + return 0;
> }
> if (hash) {
> memcpy(buf, &hash, 4);
> @@ -315,15 +320,18 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
> }
> memcpy(buf + 8, iname->name + iname->len - 16, 16);
> oname->name[0] = '_';
> - ret = digest_encode(buf, 24, oname->name + 1);
> - oname->len = ret + 1;
> - return ret + 1;
> + oname->len = 1 + digest_encode(buf, 24, oname->name + 1);
> + return 0;
> }
> EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
>
> /**
> * fscrypt_fname_usr_to_disk() - converts a filename from user space to disk
> * space
> + *
> + * The caller must have allocated sufficient memory for the @oname string.
> + *
> + * Return: 0 on success, -errno on failure
> */
> int fscrypt_fname_usr_to_disk(struct inode *inode,
> const struct qstr *iname,
> @@ -333,7 +341,7 @@ int fscrypt_fname_usr_to_disk(struct inode *inode,
> oname->name[0] = '.';
> oname->name[iname->len - 1] = '.';
> oname->len = iname->len;
> - return oname->len;
> + return 0;
> }
> if (inode->i_crypt_info)
> return fname_encrypt(inode, iname, oname);
> diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
> index 67415e0..4d4b910 100644
> --- a/fs/ext4/dir.c
> +++ b/fs/ext4/dir.c
> @@ -260,11 +260,12 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
> /* Directory is encrypted */
> err = fscrypt_fname_disk_to_usr(inode,
> 0, 0, &de_name, &fstr);
> + de_name = fstr;
> fstr.len = save_len;
> - if (err < 0)
> + if (err)
> goto errout;
> if (!dir_emit(ctx,
> - fstr.name, err,
> + de_name.name, de_name.len,
> le32_to_cpu(de->inode),
> get_dtype(sb, de->file_type)))
> goto done;
> diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
> index 4d83d9e..55aaf30 100644
> --- a/fs/ext4/symlink.c
> +++ b/fs/ext4/symlink.c
> @@ -67,14 +67,13 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
> goto errout;
>
> res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
> - if (res < 0)
> + if (res)
> goto errout;
>
> paddr = pstr.name;
>
> /* Null-terminate the name */
> - if (res <= pstr.len)
> - paddr[res] = '\0';
> + paddr[pstr.len] = '\0';
> if (cpage)
> put_page(cpage);
> set_delayed_call(done, kfree_link, paddr);
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index 73fa356..a5468c2 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -1048,7 +1048,7 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
> goto errout;
>
> res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
> - if (res < 0)
> + if (res)
> goto errout;
>
> /* this is broken symlink case */
> @@ -1060,7 +1060,7 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
> paddr = pstr.name;
>
> /* Null-terminate the name */
> - paddr[res] = '\0';
> + paddr[pstr.len] = '\0';
>
> put_page(cpage);
> set_delayed_call(done, kfree_link, paddr);
> --
> 2.8.0.rc3.226.g39d4020
>
> --
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Cheers, Andreas
On Wed, Sep 14, 2016 at 07:54:41PM -0700, Eric Biggers wrote:
> On Wed, Sep 14, 2016 at 05:10:21PM -0700, Jaegeuk Kim wrote:
> > Hi Eric,
> >
> > On Wed, Sep 14, 2016 at 04:00:45PM -0700, Eric Biggers wrote:
> > > Several filename crypto functions: fname_decrypt(),
> > > fscrypt_fname_disk_to_usr(), and fscrypt_fname_usr_to_disk(), returned
> > > the output length on success or -errno on failure. However, the output
> > > length was redundant with the value written to 'oname->len'. It is also
> > > potentially error-prone to make callers have to check for '< 0' instead
> > > of '!= 0'.
> >
> > At a glance, you missed some places like
> > - fscrypt_fname_usr_to_disk() in ext4_symlink() and f2fs_symlink()
> > - fscrypt_fname_disk_to_usr() in dx_show_leaf() and f2fs_fill_dentries()
> >
>
> Those callers don't have to be updated because they only check for an error
> value --- they don't use the return value as a length. I did check all the
> callers of fscrypt_fname_{usr_to_disk,disk_to_usr()}, and only the three I
> update in the patch used the return value as a length.
Hmm, your patch tries to change the return value and make its usage more
consistent. So, I think it should have been considered to change if (err < 0)
to if (err) entirely in order to avoid any potential mistake; this patch already
addresses it in some cases, but not all.
e.g., in f2fs_symlink,
err = fscrypt_fname_usr_to_disk(inode, &istr, &ostr);
if (err < 0)
goto err_out;
BTW, in dx_show_leaf(),
res = fscrypt_fname_disk_to_usr(dir,
0, 0, &de_name,
&fname_crypto_str);
if (res < 0)
...
IMHO, it'd be better to use err instead of {res|ret} when considering naming
convention.
Thanks,
>
> Eric
On Thu, Sep 15, 2016 at 09:54:12AM -0700, Jaegeuk Kim wrote:
>
> Hmm, your patch tries to change the return value and make its usage more
> consistent. So, I think it should have been considered to change if (err < 0)
> to if (err) entirely in order to avoid any potential mistake; this patch already
> addresses it in some cases, but not all.
>
> e.g., in f2fs_symlink,
>
> err = fscrypt_fname_usr_to_disk(inode, &istr, &ostr);
> if (err < 0)
> goto err_out;
>
> BTW, in dx_show_leaf(),
> res = fscrypt_fname_disk_to_usr(dir,
> 0, 0, &de_name,
> &fname_crypto_str);
> if (res < 0)
> ...
>
> IMHO, it'd be better to use err instead of {res|ret} when considering naming
> convention.
Well, I had wanted to avoid bloating the patch.
I do like the idea of the greater consistency, though.
I'll post a version of the patch that does as you're suggesting.
Eric