Add. Functions for reading PEM files and decoding ASN.1.

src/pem.c

@@ -0,0 +1,221 @@
+/* Copyright (C) 2007 The Written Word, Inc.  All rights reserved.
+ * Author: Simon Josefsson
+ *
+ * Redistribution and use in source and binary forms,
+ * with or without modification, are permitted provided
+ * that the following conditions are met:
+ *
+ *   Redistributions of source code must retain the above
+ *   copyright notice, this list of conditions and the
+ *   following disclaimer.
+ *
+ *   Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials
+ *   provided with the distribution.
+ *
+ *   Neither the name of the copyright holder nor the names
+ *   of any other contributors may be used to endorse or
+ *   promote products derived from this software without
+ *   specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+ * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ */
+
+#include "libssh2_priv.h"
+
+static int readline (char *line, int line_size, FILE *fp)
+{
+	if (!fgets(line, line_size, fp))
+	{
+		return -1;
+	}
+	if (*line && line[strlen(line) - 1] == '\r')
+	{
+		line[strlen(line) - 1] = '\0';
+	}
+	if (*line && line[strlen(line) - 1] == '\n')
+	{
+		line[strlen(line) - 1] = '\0';
+	}
+	return 0;
+}
+
+#define LINE_SIZE 128
+
+int _libssh2_pem_parse (LIBSSH2_SESSION *session,
+			const char *headerbegin,
+			const char *headerend,
+			FILE *fp,
+			char **data, unsigned int *datalen)
+{
+	char line[LINE_SIZE];
+	int err;
+	char *b64data = NULL;
+	unsigned int b64datalen = 0;
+
+	do
+	{
+		if (readline(line, LINE_SIZE, fp))
+		{
+			return -1;
+		}
+	}
+	while (strcmp (line, headerbegin) != 0);
+
+	*line = '\0';
+
+	do
+	{
+		if (*line)
+		{
+			char *tmp;
+			size_t linelen;
+
+			linelen = strlen (line);
+			tmp = LIBSSH2_REALLOC (session, b64data,
+					       b64datalen + linelen);
+			if (!tmp)
+			{
+				return -1;
+			}
+			memcpy (tmp + b64datalen, line, linelen);
+			b64data = tmp;
+			b64datalen += linelen;
+		}
+
+		if (readline(line, LINE_SIZE, fp))
+		{
+			return -1;
+		}
+	} while (strcmp (line, headerend) != 0);
+
+	if (libssh2_base64_decode(session, data, datalen,
+				  b64data, b64datalen))
+	{
+		return -1;
+	}
+
+	return 0;
+}
+
+static int read_asn1_length (const unsigned char *data,
+			     unsigned int datalen,
+			     unsigned int *len)
+{
+	unsigned int lenlen;
+	int nextpos;
+
+	if (datalen < 1)
+	{
+		return -1;
+	}
+	*len = data[0];
+
+	if (*len >= 0x80)
+	{
+		lenlen = *len & 0x7F;
+		*len = data[1];
+		if (1 + lenlen > datalen)
+		{
+			return -1;
+		}
+		if (lenlen > 1)
+		{
+			*len <<= 8;
+			*len |= data[2];
+		}
+	}
+	else
+	{
+		lenlen = 0;
+	}
+
+	nextpos = 1 + lenlen;
+	if (lenlen > 2 || 1 + lenlen + *len > datalen)
+	{
+		return -1;
+	}
+
+	return nextpos;
+}
+
+int _libssh2_pem_decode_sequence (char **data, unsigned int *datalen)
+{
+	unsigned int len;
+	unsigned int lenlen;
+
+	if (*datalen < 1)
+	{
+		return -1;
+	}
+
+	if ((*data)[0] != '\x30')
+	{
+		return -1;
+	}
+
+	(*data)++;
+	(*datalen)--;
+
+	lenlen = read_asn1_length (*data, *datalen, &len);
+	if (lenlen < 0 || lenlen + len != *datalen)
+	{
+		return -1;
+	}
+
+	*data += lenlen;
+	*datalen -= lenlen;
+
+	return 0;
+}
+
+int _libssh2_pem_decode_integer (char **data, unsigned int *datalen,
+				 char **i, unsigned int *ilen)
+{
+	unsigned int len;
+	unsigned int lenlen;
+
+	if (*datalen < 1)
+	{
+		return -1;
+	}
+
+	if ((*data)[0] != '\x02')
+	{
+		return -1;
+	}
+
+	(*data)++;
+	(*datalen)--;
+
+	lenlen = read_asn1_length (*data, *datalen, &len);
+	if (lenlen < 0 || lenlen + len > *datalen)
+	{
+		return -1;
+	}
+
+	*data += lenlen;
+	*datalen -= lenlen;
+
+	*i = *data;
+	*ilen = len;
+
+	*data += len;
+	*datalen -= len;
+
+	return 0;
+}