mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-26 20:44:32 +08:00
a116e1cdc6
Add RFC4648-compliant base64 encoding and decoding routines, based on the base64url encoding in fs/crypto/fname.c. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Cc: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
104 lines
2.4 KiB
C
104 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* base64.c - RFC4648-compliant base64 encoding
|
|
*
|
|
* Copyright (c) 2020 Hannes Reinecke, SUSE
|
|
*
|
|
* Based on the base64url routines from fs/crypto/fname.c
|
|
* (which are using the URL-safe base64 encoding),
|
|
* modified to use the standard coding table from RFC4648 section 4.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/types.h>
|
|
#include <linux/export.h>
|
|
#include <linux/string.h>
|
|
#include <linux/base64.h>
|
|
|
|
static const char base64_table[65] =
|
|
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
|
|
|
/**
|
|
* base64_encode() - base64-encode some binary data
|
|
* @src: the binary data to encode
|
|
* @srclen: the length of @src in bytes
|
|
* @dst: (output) the base64-encoded string. Not NUL-terminated.
|
|
*
|
|
* Encodes data using base64 encoding, i.e. the "Base 64 Encoding" specified
|
|
* by RFC 4648, including the '='-padding.
|
|
*
|
|
* Return: the length of the resulting base64-encoded string in bytes.
|
|
*/
|
|
int base64_encode(const u8 *src, int srclen, char *dst)
|
|
{
|
|
u32 ac = 0;
|
|
int bits = 0;
|
|
int i;
|
|
char *cp = dst;
|
|
|
|
for (i = 0; i < srclen; i++) {
|
|
ac = (ac << 8) | src[i];
|
|
bits += 8;
|
|
do {
|
|
bits -= 6;
|
|
*cp++ = base64_table[(ac >> bits) & 0x3f];
|
|
} while (bits >= 6);
|
|
}
|
|
if (bits) {
|
|
*cp++ = base64_table[(ac << (6 - bits)) & 0x3f];
|
|
bits -= 6;
|
|
}
|
|
while (bits < 0) {
|
|
*cp++ = '=';
|
|
bits += 2;
|
|
}
|
|
return cp - dst;
|
|
}
|
|
EXPORT_SYMBOL_GPL(base64_encode);
|
|
|
|
/**
|
|
* base64_decode() - base64-decode a string
|
|
* @src: the string to decode. Doesn't need to be NUL-terminated.
|
|
* @srclen: the length of @src in bytes
|
|
* @dst: (output) the decoded binary data
|
|
*
|
|
* Decodes a string using base64 encoding, i.e. the "Base 64 Encoding"
|
|
* specified by RFC 4648, including the '='-padding.
|
|
*
|
|
* This implementation hasn't been optimized for performance.
|
|
*
|
|
* Return: the length of the resulting decoded binary data in bytes,
|
|
* or -1 if the string isn't a valid base64 string.
|
|
*/
|
|
int base64_decode(const char *src, int srclen, u8 *dst)
|
|
{
|
|
u32 ac = 0;
|
|
int bits = 0;
|
|
int i;
|
|
u8 *bp = dst;
|
|
|
|
for (i = 0; i < srclen; i++) {
|
|
const char *p = strchr(base64_table, src[i]);
|
|
|
|
if (src[i] == '=') {
|
|
ac = (ac << 6);
|
|
bits += 6;
|
|
if (bits >= 8)
|
|
bits -= 8;
|
|
continue;
|
|
}
|
|
if (p == NULL || src[i] == 0)
|
|
return -1;
|
|
ac = (ac << 6) | (p - base64_table);
|
|
bits += 6;
|
|
if (bits >= 8) {
|
|
bits -= 8;
|
|
*bp++ = (u8)(ac >> bits);
|
|
}
|
|
}
|
|
if (ac & ((1 << bits) - 1))
|
|
return -1;
|
|
return bp - dst;
|
|
}
|
|
EXPORT_SYMBOL_GPL(base64_decode);
|