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-rw-r--r--common/mbox-util.c282
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diff --git a/common/mbox-util.c b/common/mbox-util.c
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+/* mbox-util.c - Mail address helper functions
+ * Copyright (C) 1998-2010 Free Software Foundation, Inc.
+ * Copyright (C) 1998-2015 Werner Koch
+ *
+ * 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/>.
+ */
+
+/* NB: GPGME uses the same code to reflect our idea on how to extract
+ * a mail address from a user id.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "util.h"
+#include "mbox-util.h"
+
+
+static int
+string_count_chr (const char *string, int c)
+{
+ int count;
+
+ for (count=0; *string; string++ )
+ if ( *string == c )
+ count++;
+ return count;
+}
+
+static int
+mem_count_chr (const void *buffer, int c, size_t length)
+{
+ const char *s = buffer;
+ int count;
+
+ for (count=0; length; length--, s++)
+ if (*s == c)
+ count++;
+ return count;
+}
+
+
+/* This is a case-sensitive version of our memistr. I wonder why no
+ standard function memstr exists but I better do not use the name
+ memstr to avoid future conflicts. */
+static const char *
+my_memstr (const void *buffer, size_t buflen, const char *sub)
+{
+ const unsigned char *buf = buffer;
+ const unsigned char *t = (const unsigned char *)buf;
+ const unsigned char *s = (const unsigned char *)sub;
+ size_t n = buflen;
+
+ for ( ; n ; t++, n-- )
+ {
+ if (*t == *s)
+ {
+ for (buf = t++, buflen = n--, s++; n && *t ==*s; t++, s++, n--)
+ ;
+ if (!*s)
+ return (const char*)buf;
+ t = (const unsigned char *)buf;
+ s = (const unsigned char *)sub ;
+ n = buflen;
+ }
+ }
+ return NULL;
+}
+
+
+
+static int
+string_has_ctrl_or_space (const char *string)
+{
+ for (; *string; string++ )
+ if (!(*string & 0x80) && *string <= 0x20)
+ return 1;
+ return 0;
+}
+
+
+/* Return true if STRING has two consecutive '.' after an '@'
+ sign. */
+static int
+has_dotdot_after_at (const char *string)
+{
+ string = strchr (string, '@');
+ if (!string)
+ return 0; /* No at-sign. */
+ string++;
+ return !!strstr (string, "..");
+}
+
+
+/* Check whether BUFFER has characters not valid in an RFC-822
+ address. LENGTH gives the length of BUFFER.
+
+ To cope with OpenPGP we ignore non-ascii characters so that for
+ example umlauts are legal in an email address. An OpenPGP user ID
+ must be utf-8 encoded but there is no strict requirement for
+ RFC-822. Thus to avoid IDNA encoding we put the address verbatim
+ as utf-8 into the user ID under the assumption that mail programs
+ handle IDNA at a lower level and take OpenPGP user IDs as utf-8.
+ Note that we can't do an utf-8 encoding checking here because in
+ keygen.c this function is called with the native encoding and
+ native to utf-8 encoding is only done later. */
+int
+has_invalid_email_chars (const void *buffer, size_t length)
+{
+ const unsigned char *s = buffer;
+ int at_seen=0;
+ const char *valid_chars=
+ "01234567890_-.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+ for ( ; length && *s; length--, s++ )
+ {
+ if ((*s & 0x80))
+ continue; /* We only care about ASCII. */
+ if (*s == '@')
+ at_seen=1;
+ else if (!at_seen && !(strchr (valid_chars, *s)
+ || strchr ("!#$%&'*+/=?^`{|}~", *s)))
+ return 1;
+ else if (at_seen && !strchr (valid_chars, *s))
+ return 1;
+ }
+ return 0;
+}
+
+
+/* Same as is_valid_mailbox (see below) but operates on non-nul
+ terminated buffer. */
+int
+is_valid_mailbox_mem (const void *name_arg, size_t namelen)
+{
+ const char *name = name_arg;
+
+ return !( !name
+ || !namelen
+ || has_invalid_email_chars (name, namelen)
+ || mem_count_chr (name, '@', namelen) != 1
+ || *name == '@'
+ || name[namelen-1] == '@'
+ || name[namelen-1] == '.'
+ || my_memstr (name, namelen, ".."));
+}
+
+
+/* Check whether NAME represents a valid mailbox according to
+ RFC822. Returns true if so. */
+int
+is_valid_mailbox (const char *name)
+{
+ return name? is_valid_mailbox_mem (name, strlen (name)) : 0;
+}
+
+
+/* Return the mailbox (local-part@domain) form a standard user id.
+ All plain ASCII characters in the result are converted to
+ lowercase. Caller must free the result. Returns NULL if no valid
+ mailbox was found (or we are out of memory). */
+char *
+mailbox_from_userid (const char *userid)
+{
+ const char *s, *s_end;
+ size_t len;
+ char *result = NULL;
+
+ s = strchr (userid, '<');
+ if (s)
+ {
+ /* Seems to be a standard user id. */
+ s++;
+ s_end = strchr (s, '>');
+ if (s_end && s_end > s)
+ {
+ len = s_end - s;
+ result = xtrymalloc (len + 1);
+ if (!result)
+ return NULL; /* Ooops - out of core. */
+ strncpy (result, s, len);
+ result[len] = 0;
+ /* Apply some basic checks on the address. We do not use
+ is_valid_mailbox because those checks are too strict. */
+ if (string_count_chr (result, '@') != 1 /* Need exactly one '@. */
+ || *result == '@' /* local-part missing. */
+ || result[len-1] == '@' /* domain missing. */
+ || result[len-1] == '.' /* ends with a dot. */
+ || string_has_ctrl_or_space (result)
+ || has_dotdot_after_at (result))
+ {
+ xfree (result);
+ result = NULL;
+ errno = EINVAL;
+ }
+ }
+ else
+ errno = EINVAL;
+ }
+ else if (is_valid_mailbox (userid))
+ {
+ /* The entire user id is a mailbox. Return that one. Note that
+ this fallback method has some restrictions on the valid
+ syntax of the mailbox. However, those who want weird
+ addresses should know about it and use the regular <...>
+ syntax. */
+ result = xtrystrdup (userid);
+ }
+ else
+ errno = EINVAL;
+
+ return result? ascii_strlwr (result): NULL;
+}
+
+
+/* Check whether UID is a valid standard user id of the form
+ "Heinrich Heine <heinrichh@duesseldorf.de>"
+ and return true if this is the case. */
+int
+is_valid_user_id (const char *uid)
+{
+ if (!uid || !*uid)
+ return 0;
+
+ return 1;
+}
+
+
+/* Returns true if STRING is a valid domain name according to the LDH
+ * rule. */
+int
+is_valid_domain_name (const char *string)
+{
+ static char const ldh_chars[] =
+ "01234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-";
+ const char *s;
+
+ /* Note that we do not check the length limit of a label or the
+ * entire name */
+
+ for (s=string; *s; s++)
+ if (*s == '.')
+ {
+ if (string == s)
+ return 0; /* Dot at the start of the string. */
+ /* (may also be at the end like in ".") */
+ if (s[1] == '.')
+ return 0; /* No - double dot. */
+ }
+ else if (!strchr (ldh_chars, *s))
+ return 0;
+ else if (*s == '-')
+ {
+ if (string == s)
+ return 0; /* Leading hyphen. */
+ if (s[-1] == '.')
+ return 0; /* Hyphen at begin of a label. */
+ if (s[1] == '.')
+ return 0; /* Hyphen at start of a label. */
+ if (!s[1])
+ return 0; /* Trailing hyphen. */
+ }
+
+ return !!*string;
+}