From cdccc69c62579b0c13b35fad0728079652b8f3c9 Mon Sep 17 00:00:00 2001 From: David Oberhollenzer Date: Tue, 31 Jan 2023 11:21:30 +0100 Subject: Move library source into src sub-directory Signed-off-by: David Oberhollenzer --- lib/util/src/base64_decode.c | 103 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 lib/util/src/base64_decode.c (limited to 'lib/util/src/base64_decode.c') diff --git a/lib/util/src/base64_decode.c b/lib/util/src/base64_decode.c new file mode 100644 index 0000000..b1cf5b6 --- /dev/null +++ b/lib/util/src/base64_decode.c @@ -0,0 +1,103 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +/* + * base64_decode.c + * + * Copyright (C) 2022 David Oberhollenzer + */ +#include "config.h" +#include "util/util.h" +#include "util/test.h" + +#include + +static int base64_digit(int c) +{ + if (isupper(c)) + return c - 'A'; + if (islower(c)) + return c - 'a' + 26; + if (isdigit(c)) + return c - '0' + 52; + if (c == '+') + return 62; + if (c == '/' || c == '-') + return 63; + return -1; +} + +int base64_decode(const char *in, size_t in_len, sqfs_u8 *out, size_t *out_len) +{ + int i1, i2, i3, i4; + size_t count = 0; + + while (in_len >= 4) { + i1 = base64_digit(*(in++)); + i2 = base64_digit(*(in++)); + i3 = *(in++); + i4 = *(in++); + in_len -= 4; + + if (i1 < 0 || i2 < 0 || count >= *out_len) + goto fail; + + out[count++] = (i1 << 2) | (i2 >> 4); + + if (i3 == '=' || i3 == '_') { + if ((i4 != '=' && i4 != '_') || in_len > 0) + goto fail; + break; + } + + i3 = base64_digit(i3); + if (i3 < 0 || count >= *out_len) + goto fail; + + out[count++] = ((i2 & 0x0F) << 4) | (i3 >> 2); + + if (i4 == '=' || i4 == '_') { + if (in_len > 0) + goto fail; + break; + } + + i4 = base64_digit(i4); + if (i4 < 0 || count >= *out_len) + goto fail; + + out[count++] = ((i3 & 0x3) << 6) | i4; + } + + /* libarchive has this bizarre bastardization of truncated base64 */ + if (in_len > 0) { + if (in_len == 1) + goto fail; + + i1 = base64_digit(*(in++)); + i2 = base64_digit(*(in++)); + in_len -= 2; + + if (i1 < 0 || i2 < 0 || count >= *out_len) + goto fail; + + out[count++] = (i1 << 2) | (i2 >> 4); + + if (in_len > 0) { + i3 = *(in++); + --in_len; + + if (i3 != '=' && i3 != '_') { + i3 = base64_digit(i3); + if (i3 < 0 || count >= *out_len) + goto fail; + + out[count++] = ((i2 & 0x0F) << 4) | (i3 >> 2); + } + } + } + + *out_len = count; + return 0; +fail: + *out_len = 0; + return -1; +} -- cgit v1.2.3