X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=crypt_common.c;h=8de346c74b47468a15c566cae29a4ff484b056c6;hp=05d71de4076cee75a6c285acc5bc0334dfe1db17;hb=72f53a08032153d2fd6b2b5811d797358ad86f96;hpb=96bd269d26af317ba985ad7eec7f75dec5d76bd7

diff --git a/crypt_common.c b/crypt_common.c
index 05d71de4..8de346c7 100644
--- a/crypt_common.c
+++ b/crypt_common.c
@@ -4,7 +4,7 @@
  * 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>
@@ -15,6 +15,7 @@
 #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 +55,19 @@ 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 +86,7 @@ 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 +186,17 @@ 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 +216,15 @@ 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 +239,19 @@ 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 +273,18 @@ 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;