X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=crypt_common.c;h=4e9622e4ee773d65c708bbf3f0b624592ed0e27b;hp=3bd603c0ec698ab6be9c3e48d99e7a76e52c53f0;hb=6a7ba04cacab72c9787c4b0427e36cedd5adefcf;hpb=5957ec3c6deb0a5585f979ff470e9a346154ca62

diff --git a/crypt_common.c b/crypt_common.c
index 3bd603c0..4e9622e4 100644
--- a/crypt_common.c
+++ b/crypt_common.c
@@ -1,13 +1,12 @@
 /*
- * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2012 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
-/** \file crypt_common.c Crypto functions independent of the implementation. */
+/** \file crypt_common.c Crypto functions independent of openssl/libgcrypt. */
 
 #include <regex.h>
-#include <stdbool.h>
 
 #include "para.h"
 #include "error.h"
@@ -15,6 +14,7 @@
 #include "crypt_backend.h"
 #include "crypt.h"
 
+/** If the key begins with this text, we treat it as an ssh key. */
 #define KEY_TYPE_TXT "ssh-rsa"
 
 /**
@@ -54,11 +54,19 @@ size_t is_ssh_rsa_key(char *data, size_t size)
 static const char Base64[] =
 	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 static const char Pad64 = '=';
-/*
+
+/**
+ * base64-decode a buffer.
+ *
+ * \param src The buffer to decode.
+ * \param target Result is stored here.
+ * \param targsize Number of bytes of \a target.
+ *
  * Skips all whitespace anywhere. Converts characters, four at a time, starting
  * at (or after) src from base - 64 numbers into three 8 bit bytes in the
- * target area. it returns the number of data bytes stored at the target, or -E_BASE64
- * on error.
+ * target area.
+ *
+ * \return The number of data bytes stored at the target, -E_BASE64 on errors.
  */
 int base64_decode(char const *src, unsigned char *target, size_t targsize)
 {
@@ -77,7 +85,7 @@ int base64_decode(char const *src, unsigned char *target, size_t targsize)
 			break;
 
 		pos = strchr(Base64, ch);
-		if (pos == 0) /* A non-base64 character. */
+		if (pos == NULL) /* A non-base64 character. */
 			return -E_BASE64;
 
 		switch (state) {
@@ -177,6 +185,17 @@ int base64_decode(char const *src, unsigned char *target, size_t targsize)
 	return tarindex;
 }
 
+/**
+ * uudecode a buffer.
+ *
+ * \param src The buffer to decode.
+ * \param target Result buffer.
+ * \param targsize The length of \a target in bytes.
+ *
+ * This is just a simple wrapper for base64_decode() which strips whitespace.
+ *
+ * \return The return value of the underlying call to base64_decode().
+ */
 int uudecode(const char *src, unsigned char *target, size_t targsize)
 {
 	int len;
@@ -196,9 +215,15 @@ int uudecode(const char *src, unsigned char *target, size_t targsize)
 	return len;
 }
 
-/*
- * Can not use the inline functions of portable_io.h here because the byte
- * order is different.
+/**
+ * Read a 4-byte number from a buffer in big-endian format.
+ *
+ * \param vp The buffer.
+ *
+ * The byte-order of the buffer is expected to be big-endian, unlike read_u32()
+ * of portable_io.h which expects little endian.
+ *
+ * \return The 32 bit number given by \a vp.
  */
 uint32_t read_ssh_u32(const void *vp)
 {
@@ -213,6 +238,19 @@ uint32_t read_ssh_u32(const void *vp)
 	return v;
 }
 
+/**
+ * Sanity checks for the header of an ssh key.
+ *
+ * \param blob The buffer.
+ * \param blen The number of bytes of \a blob.
+ *
+ * This performs some checks to make sure we really have an ssh key. It also
+ * computes the offset in bytes of the start of the key values (modulus,
+ * exponent..).
+ *
+ * \return The number of bytes to skip until the start of the first encoded
+ * number (usually 11).
+ */
 int check_ssh_key_header(const unsigned char *blob, int blen)
 {
 	const unsigned char *p = blob, *end = blob + blen;
@@ -234,6 +272,18 @@ int check_ssh_key_header(const unsigned char *blob, int blen)
 	return 4 + rlen;
 }
 
+/**
+ * Check existence and permissions of a key file.
+ *
+ * \param file The path of the key file.
+ * \param private_key Whether this is a private key.
+ *
+ * This checks whether the file exists. If it is a private key, we additionally
+ * check that the permissions are restrictive enough. It is considered an error
+ * if we own the file and it is readable for others.
+ *
+ * \return Standard.
+ */
 int check_key_file(const char *file, bool private_key)
 {
 	struct stat st;
@@ -247,16 +297,6 @@ int check_key_file(const char *file, bool private_key)
 	return 1;
 }
 
-/**
- * Convert a hash value to ascii format.
- *
- * \param hash the hash value.
- * \param asc Result pointer.
- *
- * \a asc must point to an area of at least 2 * \p HASH_SIZE + 1 bytes which
- * will be filled by the function with the ascii representation of the hash
- * value given by \a hash, and a terminating \p NULL byte.
- */
 void hash_to_asc(unsigned char *hash, char *asc)
 {
 	int i;
@@ -269,15 +309,6 @@ void hash_to_asc(unsigned char *hash, char *asc)
 	asc[2 * HASH_SIZE] = '\0';
 }
 
-/**
- * Compare two hashes.
- *
- * \param h1 Pointer to the first hash value.
- * \param h2 Pointer to the second hash value.
- *
- * \return 1, -1, or zero, depending on whether \a h1 is greater than,
- * less than or equal to h2, respectively.
- */
 int hash_compare(unsigned char *h1, unsigned char *h2)
 {
 	int i;
@@ -291,19 +322,6 @@ int hash_compare(unsigned char *h1, unsigned char *h2)
 	return 0;
 }
 
-/**
- * Receive a buffer, decrypt it and write terminating NULL byte.
- *
- * \param scc The context.
- * \param buf The buffer to write the decrypted data to.
- * \param size The size of \a buf.
- *
- * Read at most \a size - 1 bytes from file descriptor given by \a scc, decrypt
- * the received data and write a NULL byte at the end of the decrypted data.
- *
- * \return The return value of the underlying call to \ref
- * sc_recv_bin_buffer().
- */
 int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size)
 {
 	int n;
@@ -317,27 +335,16 @@ int sc_recv_buffer(struct stream_cipher_context *scc, char *buf, size_t size)
 	return n;
 }
 
-/**
- * Encrypt and send a \p NULL-terminated buffer.
- *
- * \param scc The context.
- * \param buf The buffer to send.
- *
- * \return The return value of the underyling call to sc_send_bin_buffer().
- */
-int sc_send_buffer(struct stream_cipher_context *scc, const char *buf)
+int sc_send_buffer(struct stream_cipher_context *scc, char *buf)
 {
-	return sc_send_bin_buffer(scc, buf, strlen(buf));
+	size_t len = strlen(buf);
+	int ret = sc_send_bin_buffer(scc, buf, len);
+
+	if (ret < 0 || ret == len)
+		return ret;
+	return -E_SHORT_WRITE;
 }
 
-/**
- * Format, encrypt and send a buffer.
- *
- * \param scc The context.
- * \param fmt A format string.
- *
- * \return The return value of the underyling call to sc_send_buffer().
- */
 __printf_2_3 int sc_send_va_buffer(struct stream_cipher_context *scc,
 		const char *fmt, ...)
 {