[OpenWrt-Devel] [PATCH] [libubox][v3] b64: add base64 support

[Jonas Gorski]

Hi,

On Mon, Apr 13, 2015 at 2:34 AM, Luka Perkov <luka at openwrt.org> wrote:
> The base code has been taken from zstream project which was
> written by Steven Barth.
>
> Signed-off-by: Luka Perkov <luka at openwrt.org>
> CC: Steven Barth <steven at midlink.org>
> ---
> => changes in v2:
>
> Use new API:
>
> size_t b64decode(void **out, const char *in, size_t len);
> size_t b64encode(char **out, const void *in, size_t len);
>
> => changes in v3:
>
> Use new API:
>
> static inline int b64_decode_size(const void *in, size_t len);
> static inline int b64_encode_size(size_t len);
>
> size_t b64decode(void *out, const void *in, size_t len);
> size_t b64encode(void *out, const void *in, size_t len);
>
> In this set a few corner cases of invalid writes in b64decode were fixed.
> Furthermore, b64decode() works fine when in == out.
>
>  CMakeLists.txt |   2 +-
>  b64.c          | 112 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  b64.h          |  60 +++++++++++++++++++++++++++++++
>  3 files changed, 173 insertions(+), 1 deletion(-)
>  create mode 100644 b64.c
>  create mode 100644 b64.h
>
> diff --git a/CMakeLists.txt b/CMakeLists.txt
> index 58381da..77f4842 100644
> --- a/CMakeLists.txt
> +++ b/CMakeLists.txt
> @@ -14,7 +14,7 @@ IF(JSONC_FOUND)
>    INCLUDE_DIRECTORIES(${JSONC_INCLUDE_DIRS})
>  ENDIF()
>
> -SET(SOURCES avl.c avl-cmp.c blob.c blobmsg.c uloop.c usock.c ustream.c ustream-fd.c vlist.c utils.c safe_list.c runqueue.c md5.c kvlist.c ulog.c)
> +SET(SOURCES avl.c avl-cmp.c blob.c blobmsg.c uloop.c usock.c ustream.c ustream-fd.c vlist.c utils.c safe_list.c runqueue.c md5.c kvlist.c ulog.c b64.c)
>
>  ADD_LIBRARY(ubox SHARED ${SOURCES})
>  ADD_LIBRARY(ubox-static STATIC ${SOURCES})
> diff --git a/b64.c b/b64.c
> new file mode 100644
> index 0000000..007fb91
> --- /dev/null
> +++ b/b64.c
> @@ -0,0 +1,112 @@
> +/*
> + * Copyright (C) 2011 Steven Barth <steven at midlink.org>
> + * Copyright (C) 2015 Luka Perkov <luka at openwrt.org>
> + *
> + * Permission to use, copy, modify, and/or distribute this software for any
> + * purpose with or without fee is hereby granted, provided that the above
> + * copyright notice and this permission notice appear in all copies.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
> + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
> + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
> + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
> + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
> + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> + */
> +
> +#include <stdint.h>
> +#include <stdlib.h>
> +
> +#include "b64.h"
> +
> +static const uint8_t b64decode_tbl[] = {
> +       0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
> +       0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
> +       0xff, 0xff, 0x00, 0xff, 0xff, 0xff, 0x00, 0x01,
> +       0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
> +       0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
> +       0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
> +       0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
> +       0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
> +       0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
> +       0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33
> +};
> +
> +size_t b64decode(void *out, const void *in, size_t len)
> +{
> +       uint8_t *o = (uint8_t *) out;
> +       const uint8_t *data = (const uint8_t *) in;
> +       size_t lenout, i, j;
> +
> +       lenout = b64_decode_size(in, len);
> +       if (!lenout)
> +               return 0;
> +
> +       uint32_t cv = 0;
> +       for (i = 0; i < (len - 4); i += 4) {
> +               cv = 0;
> +               for (j = 0; j < 4; j++) {
> +                       uint8_t c = data[i + j] - 43;
> +                       if (c > 79 || (c = b64decode_tbl[c]) == 0xff)
> +                               return 0;
> +
> +                       cv |= c;
> +                       if (j != 3)
> +                               cv <<= 6;
> +               }
> +
> +               o[2] = (uint8_t)(cv & 0xff);
> +               o[1] = (uint8_t)((cv >> 8) & 0xff);
> +               o[0] = (uint8_t)((cv >> 16) & 0xff);
> +               o += 3;
> +       }
> +
> +       if (data[len - 1] != '=')
> +               o[2] = (uint8_t)(cv & 0xff);
> +
> +       if (data[len - 1] != '=')
> +               o[1] = (uint8_t)((cv >> 8) & 0xff);

You have the same condition twice, either you intended to have them
different and this is a bug or you can merge them.


Regards
Jonas
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