127 lines
2.7 KiB
C
127 lines
2.7 KiB
C
#include "base64.h"
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#include <openssl/evp.h>
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#include <errno.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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static void remove_lf(char *b64)
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{
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while ((b64 = strchr(b64, '\n')))
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memcpy(b64, b64 + 1, strlen(b64));
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}
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static size_t base64len(const size_t n)
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{
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/* Read EVP_EncodeInit(3) for further reference. */
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return ((n / 48) * 65) + (n % 48 ? 1 + ((n / 3) + 1) * 4 : 0);
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}
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static size_t decodedlen(const size_t n)
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{
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return ((n / 64) * 48) + (n % 64 ? (n / 4) * 3 : 0);
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}
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char *base64_encode(const void *const buf, const size_t n)
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{
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EVP_ENCODE_CTX *const ctx = EVP_ENCODE_CTX_new();
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char *ret = NULL;
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unsigned char *b64 = NULL;
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if (!ctx)
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{
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fprintf(stderr, "%s: EVP_ENCODE_CTX_new failed\n", __func__);
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goto end;
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}
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const size_t b64len = base64len(n);
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if (!(b64 = malloc(b64len + 1)))
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{
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fprintf(stderr, "%s: malloc(3): %s\n", __func__, strerror(errno));
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goto end;
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}
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EVP_EncodeInit(ctx);
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size_t rem = n, done = 0;
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int outl = b64len;
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while (rem)
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{
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const size_t i = n - rem, inl = rem > 48 ? 48 : rem;
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const unsigned char *const in = buf;
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if (!EVP_EncodeUpdate(ctx, &b64[done], &outl, &in[i], inl))
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{
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fprintf(stderr, "%s: EVP_EncodeUpdate failed\n", __func__);
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goto end;
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}
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done += outl;
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rem -= inl;
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}
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EVP_EncodeFinal(ctx, b64, &outl);
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ret = (char *)b64;
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remove_lf(ret);
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end:
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if (!ret)
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free(b64);
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EVP_ENCODE_CTX_free(ctx);
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return ret;
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}
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void *base64_decode(const char *const b64, size_t *const n)
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{
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void *ret = NULL;
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const size_t len = strlen(b64), dlen = decodedlen(len);
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EVP_ENCODE_CTX *const ctx = EVP_ENCODE_CTX_new();
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unsigned char *const buf = malloc(dlen);
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if (!buf)
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{
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fprintf(stderr, "%s: malloc(3): %s\n", __func__, strerror(errno));
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goto end;
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}
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else if (!ctx)
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{
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fprintf(stderr, "%s: EVP_ENCODE_CTX_new failed\n", __func__);
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goto end;
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}
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EVP_DecodeInit(ctx);
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size_t rem = len, done = 0;
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int outl = dlen;
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while (rem)
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{
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const size_t i = len - rem, inl = rem > 64 ? 64 : rem;
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const unsigned char *const in = (const unsigned char *)b64;
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if (EVP_DecodeUpdate(ctx, &buf[done], &outl, &in[i], inl) < 0)
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{
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fprintf(stderr, "%s: EVP_EncodeUpdate failed\n", __func__);
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goto end;
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}
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done += outl;
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rem -= inl;
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}
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EVP_DecodeFinal(ctx, buf, &outl);
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*n = done;
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ret = buf;
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end:
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if (!ret)
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free(buf);
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EVP_ENCODE_CTX_free(ctx);
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return ret;
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}
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