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-rw-r--r--common/percent.c321
1 files changed, 321 insertions, 0 deletions
diff --git a/common/percent.c b/common/percent.c
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+++ b/common/percent.c
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+/* percent.c - Percent escaping
+ * Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either
+ *
+ * - the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * or
+ *
+ * - the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * or both in parallel, as here.
+ *
+ * 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 General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <ctype.h>
+#include <assert.h>
+
+#include "util.h"
+
+
+/* Create a newly alloced string from STRING with all spaces and
+ control characters converted to plus signs or %xx sequences. The
+ function returns the new string or NULL in case of a malloc
+ failure.
+
+ Note that we also escape the quote character to work around a bug
+ in the mingw32 runtime which does not correcty handle command line
+ quoting. We correctly double the quote mark when calling a program
+ (i.e. gpg-protect-tool), but the pre-main code does not notice the
+ double quote as an escaped quote. We do this also on POSIX systems
+ for consistency. */
+char *
+percent_plus_escape (const char *string)
+{
+ char *buffer, *p;
+ const char *s;
+ size_t length;
+
+ for (length=1, s=string; *s; s++)
+ {
+ if (*s == '+' || *s == '\"' || *s == '%'
+ || *(const unsigned char *)s < 0x20)
+ length += 3;
+ else
+ length++;
+ }
+
+ buffer = p = xtrymalloc (length);
+ if (!buffer)
+ return NULL;
+
+ for (s=string; *s; s++)
+ {
+ if (*s == '+' || *s == '\"' || *s == '%'
+ || *(const unsigned char *)s < 0x20)
+ {
+ snprintf (p, 4, "%%%02X", *(unsigned char *)s);
+ p += 3;
+ }
+ else if (*s == ' ')
+ *p++ = '+';
+ else
+ *p++ = *s;
+ }
+ *p = 0;
+
+ return buffer;
+
+}
+
+
+/* Create a newly malloced string from (DATA,DATALEN) with embedded
+ * nuls quoted as %00. The standard percent unescaping can be used to
+ * reverse this encoding. With PLUS_ESCAPE set plus-escaping (spaces
+ * are replaced by a '+') and escaping of characters with values less
+ * than 0x20 is used. If PREFIX is not NULL it will be prepended to
+ * the output in standard escape format; that is PLUS_ESCAPING is
+ * ignored for PREFIX. */
+char *
+percent_data_escape (int plus_escape, const char *prefix,
+ const void *data, size_t datalen)
+{
+ char *buffer, *p;
+ const unsigned char *s;
+ size_t n;
+ size_t length = 1;
+
+ if (prefix)
+ {
+ for (s = prefix; *s; s++)
+ {
+ if (*s == '%' || *s < 0x20)
+ length += 3;
+ else
+ length++;
+ }
+ }
+
+ for (s=data, n=datalen; n; s++, n--)
+ {
+ if (!*s || *s == '%' || (plus_escape && (*s < ' ' || *s == '+')))
+ length += 3;
+ else
+ length++;
+ }
+
+ buffer = p = xtrymalloc (length);
+ if (!buffer)
+ return NULL;
+
+ if (prefix)
+ {
+ for (s = prefix; *s; s++)
+ {
+ if (*s == '%' || *s < 0x20)
+ {
+ snprintf (p, 4, "%%%02X", *s);
+ p += 3;
+ }
+ else
+ *p++ = *s;
+ }
+ }
+
+ for (s=data, n=datalen; n; s++, n--)
+ {
+ if (!*s)
+ {
+ memcpy (p, "%00", 3);
+ p += 3;
+ }
+ else if (*s == '%')
+ {
+ memcpy (p, "%25", 3);
+ p += 3;
+ }
+ else if (plus_escape && *s == ' ')
+ {
+ *p++ = '+';
+ }
+ else if (plus_escape && (*s < ' ' || *s == '+'))
+ {
+ snprintf (p, 4, "%%%02X", *s);
+ p += 3;
+ }
+ else
+ *p++ = *s;
+ }
+ *p = 0;
+
+ return buffer;
+}
+
+
+/* Do the percent and plus/space unescaping from STRING to BUFFER and
+ return the length of the valid buffer. Plus unescaping is only
+ done if WITHPLUS is true. An escaped Nul character will be
+ replaced by NULREPL. */
+static size_t
+do_unescape (unsigned char *buffer, const unsigned char *string,
+ int withplus, int nulrepl)
+{
+ unsigned char *p = buffer;
+
+ while (*string)
+ {
+ if (*string == '%' && string[1] && string[2])
+ {
+ string++;
+ *p = xtoi_2 (string);
+ if (!*p)
+ *p = nulrepl;
+ string++;
+ }
+ else if (*string == '+' && withplus)
+ *p = ' ';
+ else
+ *p = *string;
+ p++;
+ string++;
+ }
+
+ return (p - buffer);
+}
+
+
+/* Count space required after unescaping STRING. Note that this will
+ never be larger than strlen (STRING). */
+static size_t
+count_unescape (const unsigned char *string)
+{
+ size_t n = 0;
+
+ while (*string)
+ {
+ if (*string == '%' && string[1] && string[2])
+ {
+ string++;
+ string++;
+ }
+ string++;
+ n++;
+ }
+
+ return n;
+}
+
+
+/* Helper. */
+static char *
+do_plus_or_plain_unescape (const char *string, int withplus, int nulrepl)
+{
+ size_t nbytes, n;
+ char *newstring;
+
+ nbytes = count_unescape (string);
+ newstring = xtrymalloc (nbytes+1);
+ if (newstring)
+ {
+ n = do_unescape (newstring, string, withplus, nulrepl);
+ assert (n == nbytes);
+ newstring[n] = 0;
+ }
+ return newstring;
+}
+
+
+/* Create a new allocated string from STRING with all "%xx" sequences
+ decoded and all plus signs replaced by a space. Embedded Nul
+ characters are replaced by the value of NULREPL. The function
+ returns the new string or NULL in case of a malloc failure. */
+char *
+percent_plus_unescape (const char *string, int nulrepl)
+{
+ return do_plus_or_plain_unescape (string, 1, nulrepl);
+}
+
+
+/* Create a new allocated string from STRING with all "%xx" sequences
+ decoded. Embedded Nul characters are replaced by the value of
+ NULREPL. The function returns the new string or NULL in case of a
+ malloc failure. */
+char *
+percent_unescape (const char *string, int nulrepl)
+{
+ return do_plus_or_plain_unescape (string, 0, nulrepl);
+}
+
+
+static size_t
+do_unescape_inplace (char *string, int withplus, int nulrepl)
+{
+ unsigned char *p, *p0;
+
+ p = p0 = string;
+ while (*string)
+ {
+ if (*string == '%' && string[1] && string[2])
+ {
+ string++;
+ *p = xtoi_2 (string);
+ if (!*p)
+ *p = nulrepl;
+ string++;
+ }
+ else if (*string == '+' && withplus)
+ *p = ' ';
+ else
+ *p = *string;
+ p++;
+ string++;
+ }
+
+ return (p - p0);
+}
+
+
+/* Perform percent and plus unescaping in STRING and return the new
+ valid length of the string. Embedded Nul characters are replaced
+ by the value of NULREPL. A terminating Nul character is not
+ inserted; the caller might want to call this function this way:
+
+ foo[percent_plus_unescape_inplace (foo, 0)] = 0;
+ */
+size_t
+percent_plus_unescape_inplace (char *string, int nulrepl)
+{
+ return do_unescape_inplace (string, 1, nulrepl);
+}
+
+
+/* Perform percent unescaping in STRING and return the new valid
+ length of the string. Embedded Nul characters are replaced by the
+ value of NULREPL. A terminating Nul character is not inserted; the
+ caller might want to call this function this way:
+
+ foo[percent_unescape_inplace (foo, 0)] = 0;
+ */
+size_t
+percent_unescape_inplace (char *string, int nulrepl)
+{
+ return do_unescape_inplace (string, 0, nulrepl);
+}
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