[Pkg-gnupg-commit] [gpgme] 182/412: core: Add a base 64 decoder.
Daniel Kahn Gillmor
dkg at fifthhorseman.net
Thu Sep 22 21:26:43 UTC 2016
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dkg pushed a commit to branch master
in repository gpgme.
commit f8b8027ae63c957557ed6bdc7e5a30ef1bdd8e77
Author: Werner Koch <wk at gnupg.org>
Date: Thu Jun 23 09:48:54 2016 +0200
core: Add a base 64 decoder.
* src/b64dec.c: New. Taken from gnupg. Prefix function names with
_gpgme_ and change to use standard C malloc functions.
* src/util.h.h (struct b64state): New.
* src/Makefile.am (main_sources): Add file.
--
The file b64dec.c has been taken from gnupg commit
e430ff6ad0b7dcfcebd92b825dd5168205447ff3
Signed-off-by: Werner Koch <wk at gnupg.org>
---
src/Makefile.am | 2 +-
src/b64dec.c | 251 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/util.h | 20 +++++
3 files changed, 272 insertions(+), 1 deletion(-)
diff --git a/src/Makefile.am b/src/Makefile.am
index 951fc00..6691540 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -74,7 +74,7 @@ endif
# right linking order with libtool, as the non-installed version has
# unresolved symbols to the thread module.
main_sources = \
- util.h conversion.c get-env.c context.h ops.h \
+ util.h conversion.c b64dec.c get-env.c context.h ops.h \
parsetlv.c parsetlv.h \
data.h data.c data-fd.c data-stream.c data-mem.c data-user.c \
data-compat.c data-identify.c \
diff --git a/src/b64dec.c b/src/b64dec.c
new file mode 100644
index 0000000..7965a30
--- /dev/null
+++ b/src/b64dec.c
@@ -0,0 +1,251 @@
+/* b64dec.c - Simple Base64 decoder.
+ * Copyright (C) 2008, 2011 Free Software Foundation, Inc.
+ * Copyright (C) 2008, 2011, 2016 g10 Code GmbH
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include "gpgme.h"
+#include "util.h"
+
+
+/* The reverse base-64 list used for base-64 decoding. */
+static unsigned char const asctobin[128] =
+ {
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0x3e, 0xff, 0xff, 0xff, 0x3f,
+ 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
+ 0x3c, 0x3d, 0xff, 0xff, 0xff, 0xff, 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, 0xff, 0xff, 0xff, 0xff, 0xff
+ };
+
+enum decoder_states
+ {
+ s_init, s_idle, s_lfseen, s_beginseen, s_waitheader, s_waitblank, s_begin,
+ s_b64_0, s_b64_1, s_b64_2, s_b64_3,
+ s_waitendtitle, s_waitend
+ };
+
+
+
+/* Initialize the context for the base64 decoder. If TITLE is NULL a
+ plain base64 decoding is done. If it is the empty string the
+ decoder will skip everything until a "-----BEGIN " line has been
+ seen, decoding ends at a "----END " line. */
+gpg_error_t
+_gpgme_b64dec_start (struct b64state *state, const char *title)
+{
+ memset (state, 0, sizeof *state);
+ if (title)
+ {
+ state->title = strdup (title);
+ if (!state->title)
+ state->lasterr = gpg_error_from_syserror ();
+ else
+ state->idx = s_init;
+ }
+ else
+ state->idx = s_b64_0;
+ return state->lasterr;
+}
+
+
+/* Do in-place decoding of base-64 data of LENGTH in BUFFER. Stores the
+ new length of the buffer at R_NBYTES. */
+gpg_error_t
+_gpgme_b64dec_proc (struct b64state *state, void *buffer, size_t length,
+ size_t *r_nbytes)
+{
+ enum decoder_states ds = state->idx;
+ unsigned char val = state->radbuf[0];
+ int pos = state->quad_count;
+ char *d, *s;
+
+ if (state->lasterr)
+ return state->lasterr;
+
+ if (state->stop_seen)
+ {
+ *r_nbytes = 0;
+ state->lasterr = gpg_error (GPG_ERR_EOF);
+ free (state->title);
+ state->title = NULL;
+ return state->lasterr;
+ }
+
+ for (s=d=buffer; length && !state->stop_seen; length--, s++)
+ {
+ again:
+ switch (ds)
+ {
+ case s_idle:
+ if (*s == '\n')
+ {
+ ds = s_lfseen;
+ pos = 0;
+ }
+ break;
+ case s_init:
+ ds = s_lfseen;
+ case s_lfseen:
+ if (*s != "-----BEGIN "[pos])
+ {
+ ds = s_idle;
+ goto again;
+ }
+ else if (pos == 10)
+ {
+ pos = 0;
+ ds = s_beginseen;
+ }
+ else
+ pos++;
+ break;
+ case s_beginseen:
+ if (*s != "PGP "[pos])
+ ds = s_begin; /* Not a PGP armor. */
+ else if (pos == 3)
+ ds = s_waitheader;
+ else
+ pos++;
+ break;
+ case s_waitheader:
+ if (*s == '\n')
+ ds = s_waitblank;
+ break;
+ case s_waitblank:
+ if (*s == '\n')
+ ds = s_b64_0; /* blank line found. */
+ else if (*s == ' ' || *s == '\r' || *s == '\t')
+ ; /* Ignore spaces. */
+ else
+ {
+ /* Armor header line. Note that we don't care that our
+ * FSM accepts a header prefixed with spaces. */
+ ds = s_waitheader; /* Wait for next header. */
+ }
+ break;
+ case s_begin:
+ if (*s == '\n')
+ ds = s_b64_0;
+ break;
+ case s_b64_0:
+ case s_b64_1:
+ case s_b64_2:
+ case s_b64_3:
+ {
+ int c;
+
+ if (*s == '-' && state->title)
+ {
+ /* Not a valid Base64 character: assume end
+ header. */
+ ds = s_waitend;
+ }
+ else if (*s == '=')
+ {
+ /* Pad character: stop */
+ if (ds == s_b64_1)
+ *d++ = val;
+ ds = state->title? s_waitendtitle : s_waitend;
+ }
+ else if (*s == '\n' || *s == ' ' || *s == '\r' || *s == '\t')
+ ; /* Skip white spaces. */
+ else if ( (*s & 0x80)
+ || (c = asctobin[*(unsigned char *)s]) == 255)
+ {
+ /* Skip invalid encodings. */
+ state->invalid_encoding = 1;
+ }
+ else if (ds == s_b64_0)
+ {
+ val = c << 2;
+ ds = s_b64_1;
+ }
+ else if (ds == s_b64_1)
+ {
+ val |= (c>>4)&3;
+ *d++ = val;
+ val = (c<<4)&0xf0;
+ ds = s_b64_2;
+ }
+ else if (ds == s_b64_2)
+ {
+ val |= (c>>2)&15;
+ *d++ = val;
+ val = (c<<6)&0xc0;
+ ds = s_b64_3;
+ }
+ else
+ {
+ val |= c&0x3f;
+ *d++ = val;
+ ds = s_b64_0;
+ }
+ }
+ break;
+ case s_waitendtitle:
+ if (*s == '-')
+ ds = s_waitend;
+ break;
+ case s_waitend:
+ if ( *s == '\n')
+ state->stop_seen = 1;
+ break;
+ default:
+ assert (!"invalid state");
+ }
+ }
+
+
+ state->idx = ds;
+ state->radbuf[0] = val;
+ state->quad_count = pos;
+ *r_nbytes = (d -(char*) buffer);
+ return 0;
+}
+
+
+/* This function needs to be called before releasing the decoder
+ state. It may return an error code in case an encoding error has
+ been found during decoding. */
+gpg_error_t
+_gpgme_b64dec_finish (struct b64state *state)
+{
+ if (state->lasterr)
+ return state->lasterr;
+
+ free (state->title);
+ state->title = NULL;
+ return state->invalid_encoding? gpg_error(GPG_ERR_BAD_DATA): 0;
+}
diff --git a/src/util.h b/src/util.h
index 9c62f57..5a0f790 100644
--- a/src/util.h
+++ b/src/util.h
@@ -147,6 +147,26 @@ gpgme_error_t _gpgme_map_gnupg_error (char *err);
int _gpgme_map_pk_algo (int algo, gpgme_protocol_t protocol);
+/*-- b64dec.c --*/
+
+struct b64state
+{
+ int idx;
+ int quad_count;
+ char *title;
+ unsigned char radbuf[4];
+ int stop_seen:1;
+ int invalid_encoding:1;
+ gpg_error_t lasterr;
+};
+
+gpg_error_t _gpgme_b64dec_start (struct b64state *state, const char *title);
+gpg_error_t _gpgme_b64dec_proc (struct b64state *state,
+ void *buffer, size_t length, size_t *r_nbytes);
+gpg_error_t _gpgme_b64dec_finish (struct b64state *state);
+
+
+
/* Retrieve the environment variable NAME and return a copy of it in a
malloc()'ed buffer in *VALUE. If the environment variable is not
set, return NULL in *VALUE. */
--
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