Adding upstream version 2.2.40.upstream/2.2.40upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 388 insertions, 0 deletions

diff --git a/common/tlv-builder.c b/common/tlv-builder.c
new file mode 100644
index 0000000..59e2691
--- /dev/null
+++ b/common/tlv-builder.c
@@ -0,0 +1,388 @@
+/* tlv-builder.c - Build DER encoded objects
+ * Copyright (C) 2020 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 <https://www.gnu.org/licenses/>.
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <gpg-error.h>
+
+#include "util.h"
+#include "tlv.h"
+
+
+struct item_s
+{
+  int class;
+  int tag;
+  unsigned int is_constructed:1; /* This is a constructed element.  */
+  unsigned int is_stop:1;        /* This is a STOP item.            */
+  const void *value;
+  size_t valuelen;
+  char *buffer;                  /* Malloced space or NULL.  */
+};
+
+
+struct tlv_builder_s
+{
+  gpg_error_t error;      /* Last error.  */
+  int use_secure;         /* Use secure memory for the result.    */
+  size_t nallocateditems; /* Number of allocated items.  */
+  size_t nitems;          /* Number of used items.  */
+  struct item_s *items;   /* Array of items.  */
+  int laststop;           /* Used as return value of compute_length.  */
+};
+
+
+/* Allocate a new TLV Builder instance.  Returns NULL on error.  If
+ * SECURE is set the final object is stored in secure memory.  */
+tlv_builder_t
+tlv_builder_new (int secure)
+{
+  tlv_builder_t tb;
+
+  tb = xtrycalloc (1, sizeof *tb);
+  if (tb && secure)
+    tb->use_secure = 1;
+  return tb;
+}
+
+
+/* Make sure the array of items is large enough for one new item.
+ * Records any error in TB and returns true in that case.  */
+static int
+ensure_space (tlv_builder_t tb)
+{
+  struct item_s *newitems;
+
+  if (!tb || tb->error)
+    return 1;
+
+  if (tb->nitems == tb->nallocateditems)
+    {
+      tb->nallocateditems += 32;
+      newitems = gpgrt_reallocarray (tb->items, tb->nitems,
+                                     tb->nallocateditems, sizeof *newitems);
+      if (!newitems)
+        tb->error = gpg_error_from_syserror ();
+      else
+        tb->items = newitems;
+    }
+  return !!tb->error;
+}
+
+
+
+/* Add a new primitive element to the builder instance TB.  The
+ * element is described by CLASS, TAG, VALUE, and VALUEEN.  CLASS and
+ * TAG must describe a primitive element and (VALUE,VALUELEN) specify
+ * its value.  The value is a pointer and its object must not be
+ * changed as long as the instance TB exists.  For a TAG_NULL no vlaue
+ * is expected.  Errors are not returned but recorded for later
+ * retrieval.  */
+void
+tlv_builder_add_ptr (tlv_builder_t tb, int class, int tag,
+                     void *value, size_t valuelen)
+{
+  if (ensure_space (tb))
+    return;
+  tb->items[tb->nitems].class    = class;
+  tb->items[tb->nitems].tag      = tag;
+  tb->items[tb->nitems].value    = value;
+  tb->items[tb->nitems].valuelen = valuelen;
+  tb->nitems++;
+}
+
+
+/* This is the same as tlv_builder_add_ptr but it takes a copy of the
+ * value and thus the caller does not need to care about it.  */
+void
+tlv_builder_add_val (tlv_builder_t tb, int class, int tag,
+                     const void *value, size_t valuelen)
+{
+  void *p;
+
+  if (ensure_space (tb))
+    return;
+  if (!value || !valuelen)
+    {
+      tb->error = gpg_error (GPG_ERR_INV_VALUE);
+      return;
+    }
+  p = tb->use_secure? xtrymalloc_secure (valuelen) : xtrymalloc (valuelen);
+  if (!p)
+    {
+      tb->error = gpg_error_from_syserror ();
+      return;
+    }
+  memcpy (p, value, valuelen);
+  tb->items[tb->nitems].buffer   = p;
+  tb->items[tb->nitems].class    = class;
+  tb->items[tb->nitems].tag      = tag;
+  tb->items[tb->nitems].value    = p;
+  tb->items[tb->nitems].valuelen = valuelen;
+  tb->nitems++;
+}
+
+
+/* Add a new constructed object to the builder instance TB.  The
+ * object is described by CLASS and TAG which must describe a
+ * constructed object.  The elements of the constructed objects are
+ * added with more call to the add functions.  To close a constructed
+ * element a call to tlv_builer_add_end is required.  Errors are not
+ * returned but recorded for later retrieval.  */
+void
+tlv_builder_add_tag (tlv_builder_t tb, int class, int tag)
+{
+  if (ensure_space (tb))
+    return;
+  tb->items[tb->nitems].class    = class;
+  tb->items[tb->nitems].tag      = tag;
+  tb->items[tb->nitems].is_constructed = 1;
+  tb->nitems++;
+}
+
+
+/* A call to this function closes a constructed element.  This must be
+ * called even for an empty constructed element.  */
+void
+tlv_builder_add_end (tlv_builder_t tb)
+{
+  if (ensure_space (tb))
+    return;
+  tb->items[tb->nitems].is_stop = 1;
+  tb->nitems++;
+}
+
+
+/* Compute and set the length of all constructed elements in the item
+ * array of TB starting at IDX up to the corresponding stop item.  On
+ * error tb->error is set.  */
+static size_t
+compute_lengths (tlv_builder_t tb, int idx)
+{
+  size_t total = 0;
+
+  if (tb->error)
+    return 0;
+
+  for (; idx < tb->nitems; idx++)
+    {
+      if (tb->items[idx].is_stop)
+        {
+          tb->laststop = idx;
+          break;
+        }
+      if (tb->items[idx].is_constructed)
+        {
+          tb->items[idx].valuelen = compute_lengths (tb, idx+1);
+          if (tb->error)
+            return 0;
+          /* Note: The last processed IDX is stored at tb->LASTSTOP.  */
+        }
+      total += get_tlv_length (tb->items[idx].class, tb->items[idx].tag,
+                               tb->items[idx].is_constructed,
+                               tb->items[idx].valuelen);
+      if (tb->items[idx].is_constructed)
+        idx = tb->laststop;
+    }
+  return total;
+}
+
+
+/* Return the constructed DER encoding and release this instance.  On
+ * success the object is stored at R_OBJ and its length at R_OBJLEN.
+ * The caller needs to release that memory.  On error NULL is stored
+ * at R_OBJ and an error code is returned.  Note than an error may
+ * stem from any of the previous call made to this object or from
+ * constructing the the DER object.  */
+gpg_error_t
+tlv_builder_finalize (tlv_builder_t tb, void **r_obj, size_t *r_objlen)
+{
+  gpg_error_t err;
+  membuf_t  mb;
+  int mb_initialized = 0;
+  int idx;
+
+  *r_obj = NULL;
+  *r_objlen = 0;
+
+  if (!tb)
+    return gpg_error (GPG_ERR_INTERNAL);
+  if (tb->error)
+    {
+      err = tb->error;
+      goto leave;
+    }
+  if (!tb->nitems || !tb->items[tb->nitems-1].is_stop)
+    {
+      err = gpg_error (GPG_ERR_NO_OBJ);
+      goto leave;
+    }
+
+  compute_lengths (tb, 0);
+  err = tb->error;
+  if (err)
+    goto leave;
+
+  /* for (idx=0; idx < tb->nitems; idx++) */
+  /*   log_debug ("TLVB[%2d]: c=%d t=%2d %s p=%p l=%zu\n", */
+  /*              idx, */
+  /*              tb->items[idx].class, */
+  /*              tb->items[idx].tag, */
+  /*              tb->items[idx].is_stop? "stop": */
+  /*              tb->items[idx].is_constructed? "cons":"prim", */
+  /*              tb->items[idx].value, */
+  /*              tb->items[idx].valuelen); */
+
+  if (tb->use_secure)
+    init_membuf_secure (&mb, 512);
+  else
+    init_membuf (&mb, 512);
+  mb_initialized = 1;
+
+  for (idx=0; idx < tb->nitems; idx++)
+    {
+      if (tb->items[idx].is_stop)
+        continue;
+      put_tlv_to_membuf (&mb, tb->items[idx].class, tb->items[idx].tag,
+                         tb->items[idx].is_constructed,
+                         tb->items[idx].valuelen);
+      if (tb->items[idx].value)
+        put_membuf (&mb, tb->items[idx].value, tb->items[idx].valuelen);
+    }
+
+  *r_obj = get_membuf (&mb, r_objlen);
+  if (!*r_obj)
+    err = gpg_error_from_syserror ();
+  mb_initialized = 0;
+
+ leave:
+  if (mb_initialized)
+    xfree (get_membuf (&mb, NULL));
+  for (idx=0; idx < tb->nitems; idx++)
+    xfree (tb->items[idx].buffer);
+  xfree (tb->items);
+  xfree (tb);
+  return err;
+}
+
+
+/* Write TAG of CLASS to MEMBUF.  CONSTRUCTED is a flag telling
+ * whether the value is constructed.  LENGTH gives the length of the
+ * value, if it is 0 undefinite length is assumed.  LENGTH is ignored
+ * for the NULL tag.  TAG must be less that 0x1f.  */
+void
+put_tlv_to_membuf (membuf_t *membuf, int class, int tag,
+                   int constructed, size_t length)
+{
+  unsigned char buf[20];
+  int buflen = 0;
+  int i;
+
+  if (tag < 0x1f)
+    {
+      *buf = (class << 6) | tag;
+      if (constructed)
+        *buf |= 0x20;
+      buflen++;
+    }
+  else
+    BUG ();
+
+  if (!tag && !class)
+    buf[buflen++] = 0; /* end tag */
+  else if (tag == TAG_NULL && !class)
+    buf[buflen++] = 0; /* NULL tag */
+  else if (!length)
+    buf[buflen++] = 0x80; /* indefinite length */
+  else if (length < 128)
+    buf[buflen++] = length;
+  else
+    {
+      /* If we know the sizeof a size_t we could support larger
+       * objects - however this is pretty ridiculous */
+      i = (length <= 0xff ? 1:
+           length <= 0xffff ? 2:
+           length <= 0xffffff ? 3: 4);
+
+      buf[buflen++] = (0x80 | i);
+      if (i > 3)
+        buf[buflen++] = length >> 24;
+      if (i > 2)
+        buf[buflen++] = length >> 16;
+      if (i > 1)
+        buf[buflen++] = length >> 8;
+      buf[buflen++] = length;
+    }
+
+  put_membuf (membuf, buf, buflen);
+}
+
+
+/* Return the length of the to be constructed TLV.  CONSTRUCTED is a
+ * flag telling whether the value is constructed.  LENGTH gives the
+ * length of the value, if it is 0 undefinite length is assumed.
+ * LENGTH is ignored for the NULL tag.  TAG must be less that 0x1f.  */
+size_t
+get_tlv_length (int class, int tag, int constructed, size_t length)
+{
+  size_t buflen = 0;
+  int i;
+
+  (void)constructed;  /* Not used, but passed for uniformity of such calls.  */
+
+  /* coverity[identical_branches] */
+  if (tag < 0x1f)
+    {
+      buflen++;
+    }
+  else
+    {
+      buflen++; /* assume one and let the actual write function bail out */
+    }
+
+  if (!tag && !class)
+    buflen++; /* end tag */
+  else if (tag == TAG_NULL && !class)
+    buflen++; /* NULL tag */
+  else if (!length)
+    buflen++; /* indefinite length */
+  else if (length < 128)
+    buflen++;
+  else
+    {
+      i = (length <= 0xff ? 1:
+           length <= 0xffff ? 2:
+           length <= 0xffffff ? 3: 4);
+
+      buflen++;
+      if (i > 3)
+        buflen++;
+      if (i > 2)
+        buflen++;
+      if (i > 1)
+        buflen++;
+      buflen++;
+    }
+
+  return buflen + length;
+}