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Cleaned up the random code, use /dev/random by default,

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and remove the addrandom() function which wasn't used.

--HG--
extra : convert_revision : d560d214ad20001f8ef5d5494ff3c97e6184d9cc
This commit is contained in:
Matt Johnston 2004-12-20 13:11:15 +00:00
parent 8b32e8a08c
commit 42c691a051
2 changed files with 28 additions and 38 deletions

36
options.h
View File

@ -128,19 +128,21 @@ etc) slower (perhaps by 50%). Recommended for most small systems. */
#define ENABLE_CLI_PASSWORD_AUTH
#define ENABLE_CLI_PUBKEY_AUTH
/* Random device to use - you must specify _one only_.
* DEV_URANDOM is recommended on hosts with a good /dev/urandom, otherwise use
* PRNGD and run prngd, specifying the socket. This device must be able to
* produce a large amount of random data, so using /dev/random or Entropy
* Gathering Daemon (egd) may result in halting, as it waits for more random
* data */
#define DROPBEAR_DEV_URANDOM /* use /dev/urandom */
/* Random device to use - define either DROPBEAR_RANDOM_DEV or
* DROPBEAR_PRNGD_SOCKET.
* DROPBEAR_RANDOM_DEV is recommended on hosts with a good /dev/(u)random,
* otherwise use run prngd (or egd if you want), specifying the socket.
* The device will be queried for a few dozen bytes of seed a couple of times
* per session (or more for very long-lived sessions). */
/*#undef DROPBEAR_PRNGD */ /* use prngd socket - you must manually set up prngd
to produce output */
#ifndef DROPBEAR_PRNGD_SOCKET
#define DROPBEAR_PRNGD_SOCKET "/var/run/dropbear-rng"
#endif
/* If you are lacking entropy on the system then using /dev/urandom
* will prevent Dropbear from blocking on the device. This could
* however significantly reduce the security of your ssh connections
* if the PRNG state becomes simpler. */
#define DROPBEAR_RANDOM_DEV "/dev/random"
/* prngd must be manually set up to produce output */
/*#define DROPBEAR_PRNGD_SOCKET "/var/run/dropbear-rng"*/
/* Specify the number of clients we will allow to be connected but
* not yet authenticated. After this limit, connections are rejected */
@ -213,8 +215,6 @@ etc) slower (perhaps by 50%). Recommended for most small systems. */
#define MAX_BANNER_SIZE 2000 /* this is 25*80 chars, any more is foolish */
#define MAX_BANNER_LINES 20 /* How many lines the client will display */
#define DEV_URANDOM "/dev/urandom"
/* the number of NAME=VALUE pairs to malloc for environ, if we don't have
* the clearenv() function */
#define ENV_SIZE 100
@ -336,6 +336,14 @@ etc) slower (perhaps by 50%). Recommended for most small systems. */
#error "You can't turn on PASSWORD and PAM auth both at once. Fix it in options.h"
#endif
#if defined(DROPBEAR_RANDOM_DEV) && defined(DROPBEAR_PRNGD_SOCKET)
#error "You can't turn on DROPBEAR_PRNGD_SOCKET and DROPBEAR_RANDOM_DEV at once"
#endif
#if !defined(DROPBEAR_RANDOM_DEV) && !defined(DROPBEAR_PRNGD_SOCKET)
#error "You must choose one of DROPBEAR_PRNGD_SOCKET or DROPBEAR_RANDOM_DEV in options.h"
#endif
/* We use dropbear_client and dropbear_server as shortcuts to avoid redundant
* code, if we're just compiling as client or server */
#if defined(DROPBEAR_SERVER) && defined(DROPBEAR_CLIENT)

30
random.c
View File

@ -38,7 +38,7 @@ unsigned char hashpool[SHA1_HASH_SIZE];
static void readrand(unsigned char* buf, unsigned int buflen);
/* The basic setup is we read some data from DEV_URANDOM or PRNGD and hash it
/* The basic setup is we read some data from /dev/(u)random or prngd and hash it
* into hashpool. To read data, we hash together current hashpool contents,
* and a counter. We feed more data in by hashing the current pool and new
* data into the pool.
@ -53,19 +53,19 @@ static void readrand(unsigned char* buf, unsigned int buflen) {
int readfd;
unsigned int readpos;
int readlen;
#ifdef DROPBEAR_EGD
#ifdef DROPBEAR_PRNGD_SOCKET
struct sockaddr_un egdsock;
char egdcmd[2];
#endif
#ifdef DROPBEAR_DEV_URANDOM
readfd = open(DEV_URANDOM, O_RDONLY);
#ifdef DROPBEAR_RANDOM_DEV
readfd = open(DROPBEAR_RANDOM_DEV, O_RDONLY);
if (readfd < 0) {
dropbear_exit("couldn't open random device");
}
#endif
#ifdef DROPBEAR_EGD
#ifdef DROPBEAR_PRNGD_SOCKET
memset((void*)&egdsock, 0x0, sizeof(egdsock));
egdsock.sun_family = AF_UNIX;
strlcpy(egdsock.sun_path, DROPBEAR_EGD_SOCKET,
@ -105,7 +105,7 @@ static void readrand(unsigned char* buf, unsigned int buflen) {
close (readfd);
}
/* initialise the prng from /dev/urandom or prngd */
/* initialise the prng from /dev/(u)random or prngd */
void seedrandom() {
unsigned char readbuf[INIT_SEED_SIZE];
@ -159,21 +159,3 @@ void genrandom(unsigned char* buf, unsigned int len) {
}
m_burn(hash, sizeof(hash));
}
/* Adds entropy to the PRNG state. As long as the hash is strong, then we
* don't need to worry about entropy being added "diluting" the current
* state - it should only make it stronger. */
void addrandom(unsigned char* buf, unsigned int len) {
hash_state hs;
if (!donerandinit) {
dropbear_exit("seedrandom not done");
}
sha1_init(&hs);
sha1_process(&hs, (void*)buf, len);
sha1_process(&hs, (void*)hashpool, sizeof(hashpool));
sha1_done(&hs, hashpool);
counter = 0;
}