From: Eric Biggers <ebiggers@xxxxxxxxxx>
Some minor cleanups for the code that base64 encodes and decodes
encrypted filenames and long name digests:
- Rename "digest_{encode,decode}()" => "base64_{encode,decode}()" since
they are used for filenames too, not just for long name digests.
- Replace 'while' loops with more conventional 'for' loops.
- Use 'u8' for binary data. Keep 'char' for string data.
- Fully constify the lookup table (pointer was not const).
- Improve comment.
No actual change in behavior.
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
fs/crypto/fname.c | 34 +++++++++++++++++-----------------
1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 00d150ff30332b..6f9daba991684e 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -127,44 +127,45 @@ static int fname_decrypt(struct inode *inode,
return 0;
}
-static const char *lookup_table =
+static const char lookup_table[65] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
#define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)
/**
- * digest_encode() -
+ * base64_encode() -
*
- * Encodes the input digest using characters from the set [a-zA-Z0-9_+].
+ * Encodes the input string using characters from the set [A-Za-z0-9+,].
* The encoded string is roughly 4/3 times the size of the input string.
+ *
+ * Return: length of the encoded string
*/
-static int digest_encode(const char *src, int len, char *dst)
+static int base64_encode(const u8 *src, int len, char *dst)
{
- int i = 0, bits = 0, ac = 0;
+ int i, bits = 0, ac = 0;
char *cp = dst;
- while (i < len) {
- ac += (((unsigned char) src[i]) << bits);
+ for (i = 0; i < len; i++) {
+ ac += src[i] << bits;
bits += 8;
do {
*cp++ = lookup_table[ac & 0x3f];
ac >>= 6;
bits -= 6;
} while (bits >= 6);
- i++;
}
if (bits)
*cp++ = lookup_table[ac & 0x3f];
return cp - dst;
}
-static int digest_decode(const char *src, int len, char *dst)
+static int base64_decode(const char *src, int len, u8 *dst)
{
- int i = 0, bits = 0, ac = 0;
+ int i, bits = 0, ac = 0;
const char *p;
- char *cp = dst;
+ u8 *cp = dst;
- while (i < len) {
+ for (i = 0; i < len; i++) {
p = strchr(lookup_table, src[i]);
if (p == NULL || src[i] == 0)
return -2;
@@ -175,7 +176,6 @@ static int digest_decode(const char *src, int len, char *dst)
ac >>= 8;
bits -= 8;
}
- i++;
}
if (ac)
return -1;
@@ -272,7 +272,7 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
return fname_decrypt(inode, iname, oname);
if (iname->len <= FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE) {
- oname->len = digest_encode(iname->name, iname->len,
+ oname->len = base64_encode(iname->name, iname->len,
oname->name);
return 0;
}
@@ -287,7 +287,7 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
FSCRYPT_FNAME_DIGEST(iname->name, iname->len),
FSCRYPT_FNAME_DIGEST_SIZE);
oname->name[0] = '_';
- oname->len = 1 + digest_encode((const char *)&digested_name,
+ oname->len = 1 + base64_encode((const u8 *)&digested_name,
sizeof(digested_name), oname->name + 1);
return 0;
}
@@ -380,8 +380,8 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
if (fname->crypto_buf.name == NULL)
return -ENOMEM;
- ret = digest_decode(iname->name + digested, iname->len - digested,
- fname->crypto_buf.name);
+ ret = base64_decode(iname->name + digested, iname->len - digested,
+ fname->crypto_buf.name);
if (ret < 0) {
ret = -ENOENT;
goto errout;
--
2.22.0.657.g960e92d24f-goog
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