cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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armor.c (1982B)

      1// SPDX-License-Identifier: GPL-2.0
      2
      3#include <linux/errno.h>
      4
      5int ceph_armor(char *dst, const char *src, const char *end);
      6int ceph_unarmor(char *dst, const char *src, const char *end);
      7
      8/*
      9 * base64 encode/decode.
     10 */
     11
     12static const char *pem_key =
     13	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
     14
     15static int encode_bits(int c)
     16{
     17	return pem_key[c];
     18}
     19
     20static int decode_bits(char c)
     21{
     22	if (c >= 'A' && c <= 'Z')
     23		return c - 'A';
     24	if (c >= 'a' && c <= 'z')
     25		return c - 'a' + 26;
     26	if (c >= '0' && c <= '9')
     27		return c - '0' + 52;
     28	if (c == '+')
     29		return 62;
     30	if (c == '/')
     31		return 63;
     32	if (c == '=')
     33		return 0; /* just non-negative, please */
     34	return -EINVAL;
     35}
     36
     37int ceph_armor(char *dst, const char *src, const char *end)
     38{
     39	int olen = 0;
     40	int line = 0;
     41
     42	while (src < end) {
     43		unsigned char a, b, c;
     44
     45		a = *src++;
     46		*dst++ = encode_bits(a >> 2);
     47		if (src < end) {
     48			b = *src++;
     49			*dst++ = encode_bits(((a & 3) << 4) | (b >> 4));
     50			if (src < end) {
     51				c = *src++;
     52				*dst++ = encode_bits(((b & 15) << 2) |
     53						     (c >> 6));
     54				*dst++ = encode_bits(c & 63);
     55			} else {
     56				*dst++ = encode_bits((b & 15) << 2);
     57				*dst++ = '=';
     58			}
     59		} else {
     60			*dst++ = encode_bits(((a & 3) << 4));
     61			*dst++ = '=';
     62			*dst++ = '=';
     63		}
     64		olen += 4;
     65		line += 4;
     66		if (line == 64) {
     67			line = 0;
     68			*(dst++) = '\n';
     69			olen++;
     70		}
     71	}
     72	return olen;
     73}
     74
     75int ceph_unarmor(char *dst, const char *src, const char *end)
     76{
     77	int olen = 0;
     78
     79	while (src < end) {
     80		int a, b, c, d;
     81
     82		if (src[0] == '\n') {
     83			src++;
     84			continue;
     85		}
     86		if (src + 4 > end)
     87			return -EINVAL;
     88		a = decode_bits(src[0]);
     89		b = decode_bits(src[1]);
     90		c = decode_bits(src[2]);
     91		d = decode_bits(src[3]);
     92		if (a < 0 || b < 0 || c < 0 || d < 0)
     93			return -EINVAL;
     94
     95		*dst++ = (a << 2) | (b >> 4);
     96		if (src[2] == '=')
     97			return olen + 1;
     98		*dst++ = ((b & 15) << 4) | (c >> 2);
     99		if (src[3] == '=')
    100			return olen + 2;
    101		*dst++ = ((c & 3) << 6) | d;
    102		olen += 3;
    103		src += 4;
    104	}
    105	return olen;
    106}