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`ssh-log-pw-blank': known password fields are now omitted from SSH packet logs

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by default (although they can be included). There's also an option to remove
session data, which is good both for privacy and for reducing the size of
logfiles.

[originally from svn r4593]
This commit is contained in:
Jacob Nevins
2004-10-02 00:33:27 +00:00
parent fb92f118bd
commit e375ba107d
7 changed files with 311 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

190
ssh.c
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@ -267,7 +267,13 @@ static char *ssh2_pkt_type(int pkt_ctx, int type)
(cp)[2] = (unsigned char)((value) >> 8); \
(cp)[3] = (unsigned char)(value); }
enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
/* Enumeration values for fields in SSH-1 packets */
enum {
PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM,
/* These values are for communicating relevant semantics of
* fields to the packet logging code. */
PKTT_OTHER, PKTT_PASSWORD, PKTT_DATA
};
/*
* Coroutine mechanics for the sillier bits of the code. If these
@ -597,6 +603,13 @@ struct ssh_tag {
unsigned char *deferred_send_data;
int deferred_len, deferred_size;
/*
* State associated with packet logging
*/
int pktout_logmode;
int pktout_nblanks;
struct logblank_t *pktout_blanks;
/*
* Gross hack: pscp will try to start SFTP but fall back to
* scp1 if that fails. This variable is the means by which
@ -684,6 +697,25 @@ static void logeventf(Ssh ssh, const char *fmt, ...)
sfree(text); \
} while (0)
/* Functions to leave bits out of the SSH packet log file. */
static void dont_log_password(Ssh ssh, int blanktype)
{
if (ssh->cfg.logomitpass)
ssh->pktout_logmode = blanktype;
}
static void dont_log_data(Ssh ssh, int blanktype)
{
if (ssh->cfg.logomitdata)
ssh->pktout_logmode = blanktype;
}
static void end_log_omission(Ssh ssh)
{
ssh->pktout_logmode = PKTLOG_EMIT;
}
static int ssh_channelcmp(void *av, void *bv)
{
struct ssh_channel *a = (struct ssh_channel *) av;
@ -898,11 +930,34 @@ static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
ssh->pktin.type = ssh->pktin.body[-1];
if (ssh->logctx)
/*
* Log incoming packet, possibly omitting sensitive fields.
*/
if (ssh->logctx) {
int nblanks = 0;
struct logblank_t blank;
if (ssh->cfg.logomitdata) {
int do_blank = FALSE, blank_prefix = 0;
/* "Session data" packets - omit the data field */
if ((ssh->pktin.type == SSH1_SMSG_STDOUT_DATA) ||
(ssh->pktin.type == SSH1_SMSG_STDERR_DATA)) {
do_blank = TRUE; blank_prefix = 0;
} else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
do_blank = TRUE; blank_prefix = 4;
}
if (do_blank) {
blank.offset = blank_prefix;
blank.len = ssh->pktin.length;
blank.type = PKTLOG_OMIT;
nblanks = 1;
}
}
log_packet(ssh->logctx,
PKT_INCOMING, ssh->pktin.type,
ssh1_pkt_type(ssh->pktin.type),
ssh->pktin.body, ssh->pktin.length);
ssh->pktin.body, ssh->pktin.length,
nblanks, &blank);
}
if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
@ -1079,10 +1134,32 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
ssh->pktin.body = ssh->pktin.data;
ssh->pktin.type = ssh->pktin.data[5];
if (ssh->logctx)
/*
* Log incoming packet, possibly omitting sensitive fields.
*/
if (ssh->logctx) {
int nblanks = 0;
struct logblank_t blank;
if (ssh->cfg.logomitdata) {
int do_blank = FALSE, blank_prefix = 0;
/* "Session data" packets - omit the data field */
if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA) {
do_blank = TRUE; blank_prefix = 4;
} else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
do_blank = TRUE; blank_prefix = 8;
}
if (do_blank) {
blank.offset = blank_prefix;
blank.len = (ssh->pktin.length-6) - blank_prefix;
blank.type = PKTLOG_OMIT;
nblanks = 1;
}
}
log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
ssh->pktin.data+6, ssh->pktin.length-6);
ssh->pktin.data+6, ssh->pktin.length-6,
nblanks, &blank);
}
switch (ssh->pktin.type) {
/*
@ -1215,6 +1292,9 @@ static void s_wrpkt_start(Ssh ssh, int type, int len)
{
ssh1_pktout_size(ssh, len);
ssh->pktout.type = type;
/* Initialise log omission state */
ssh->pktout_nblanks = 0;
ssh->pktout_blanks = NULL;
}
static int s_wrpkt_prepare(Ssh ssh)
@ -1237,7 +1317,10 @@ static int s_wrpkt_prepare(Ssh ssh)
if (ssh->logctx)
log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
ssh1_pkt_type(ssh->pktout.type),
ssh->pktout.body, ssh->pktout.length);
ssh->pktout.body, ssh->pktout.length,
ssh->pktout_nblanks, ssh->pktout_blanks);
sfree(ssh->pktout_blanks); ssh->pktout_blanks = NULL;
ssh->pktout_nblanks = 0;
if (ssh->v1_compressing) {
unsigned char *compblk;
@ -1324,6 +1407,11 @@ static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
bn = va_arg(ap1, Bignum);
pktlen += ssh1_bignum_length(bn);
break;
case PKTT_PASSWORD:
case PKTT_DATA:
case PKTT_OTHER:
/* ignore this pass */
break;
default:
assert(0);
}
@ -1333,34 +1421,58 @@ static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
p = ssh->pktout.body;
while ((argtype = va_arg(ap2, int)) != PKT_END) {
int offset = p - ssh->pktout.body, len = 0;
switch (argtype) {
/* Actual fields in the packet */
case PKT_INT:
argint = va_arg(ap2, int);
PUT_32BIT(p, argint);
p += 4;
len = 4;
break;
case PKT_CHAR:
argchar = (unsigned char) va_arg(ap2, int);
*p = argchar;
p++;
len = 1;
break;
case PKT_DATA:
argp = va_arg(ap2, unsigned char *);
arglen = va_arg(ap2, int);
memcpy(p, argp, arglen);
p += arglen;
len = arglen;
break;
case PKT_STR:
argp = va_arg(ap2, unsigned char *);
arglen = strlen((char *)argp);
PUT_32BIT(p, arglen);
memcpy(p + 4, argp, arglen);
p += 4 + arglen;
len = arglen + 4;
break;
case PKT_BIGNUM:
bn = va_arg(ap2, Bignum);
p += ssh1_write_bignum(p, bn);
len = ssh1_write_bignum(p, bn);
break;
/* Tokens for modifications to packet logging */
case PKTT_PASSWORD:
dont_log_password(ssh, PKTLOG_BLANK);
break;
case PKTT_DATA:
dont_log_data(ssh, PKTLOG_OMIT);
break;
case PKTT_OTHER:
end_log_omission(ssh);
break;
}
p += len;
/* Deal with logfile omission, if required. */
if (len && (ssh->pktout_logmode != PKTLOG_EMIT)) {
ssh->pktout_nblanks++;
ssh->pktout_blanks = sresize(ssh->pktout_blanks,
ssh->pktout_nblanks,
struct logblank_t);
ssh->pktout_blanks[ssh->pktout_nblanks-1].offset = offset;
ssh->pktout_blanks[ssh->pktout_nblanks-1].len = len;
ssh->pktout_blanks[ssh->pktout_nblanks-1].type =
ssh->pktout_logmode;
}
}
}
@ -1439,6 +1551,15 @@ static void ssh2_pkt_ensure(Ssh ssh, int length)
}
static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
{
if (ssh->pktout_logmode != PKTLOG_EMIT) {
ssh->pktout_nblanks++;
ssh->pktout_blanks = sresize(ssh->pktout_blanks, ssh->pktout_nblanks,
struct logblank_t);
ssh->pktout_blanks[ssh->pktout_nblanks-1].offset =
ssh->pktout.length - 6;
ssh->pktout_blanks[ssh->pktout_nblanks-1].len = len;
ssh->pktout_blanks[ssh->pktout_nblanks-1].type = ssh->pktout_logmode;
}
ssh->pktout.length += len;
ssh2_pkt_ensure(ssh, ssh->pktout.length);
memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
@ -1450,6 +1571,7 @@ static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
static void ssh2_pkt_init(Ssh ssh, int pkt_type)
{
ssh->pktout.length = 5;
ssh->pktout_nblanks = 0; ssh->pktout_blanks = NULL;
ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
}
static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
@ -1523,7 +1645,10 @@ static int ssh2_pkt_construct(Ssh ssh)
if (ssh->logctx)
log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
ssh->pktout.data + 6, ssh->pktout.length - 6);
ssh->pktout.data + 6, ssh->pktout.length - 6,
ssh->pktout_nblanks, ssh->pktout_blanks);
sfree(ssh->pktout_blanks); ssh->pktout_blanks = NULL;
ssh->pktout_nblanks = 0;
/*
* Compress packet payload.
@ -2376,8 +2501,10 @@ static void ssh_agentf_callback(void *cv, void *reply, int replylen)
} else {
send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
PKT_INT, c->remoteid,
PKTT_DATA,
PKT_INT, replylen,
PKT_DATA, sentreply, replylen,
PKTT_OTHER,
PKT_END);
}
if (reply)
@ -3154,10 +3281,11 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
randomstr = snewn(top + 1, char);
for (i = bottom; i <= top; i++) {
if (i == pwlen)
if (i == pwlen) {
defer_packet(ssh, s->pwpkt_type,
PKT_STR, s->password, PKT_END);
else {
PKTT_PASSWORD, PKT_STR, s->password,
PKTT_OTHER, PKT_END);
} else {
for (j = 0; j < i; j++) {
do {
randomstr[j] = random_byte();
@ -3194,8 +3322,9 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
ss = s->password;
}
logevent("Sending length-padded password");
send_packet(ssh, s->pwpkt_type, PKT_INT, len,
PKT_DATA, ss, len, PKT_END);
send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
PKT_INT, len, PKT_DATA, ss, len,
PKTT_OTHER, PKT_END);
} else {
/*
* The server has _both_
@ -3206,11 +3335,14 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
int len;
len = strlen(s->password);
logevent("Sending unpadded password");
send_packet(ssh, s->pwpkt_type, PKT_INT, len,
PKT_DATA, s->password, len, PKT_END);
send_packet(ssh, s->pwpkt_type,
PKTT_PASSWORD, PKT_INT, len,
PKT_DATA, s->password, len,
PKTT_OTHER, PKT_END);
}
} else {
send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
PKT_STR, s->password, PKTT_OTHER, PKT_END);
}
}
logevent("Sent password");
@ -3282,7 +3414,9 @@ int sshfwd_write(struct ssh_channel *c, char *buf, int len)
if (ssh->version == 1) {
send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
PKT_INT, c->remoteid,
PKT_INT, len, PKT_DATA, buf, len, PKT_END);
PKTT_DATA,
PKT_INT, len, PKT_DATA, buf, len,
PKTT_OTHER, PKT_END);
/*
* In SSH1 we can return 0 here - implying that forwarded
* connections are never individually throttled - because
@ -3928,8 +4062,9 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
} else {
while (inlen > 0) {
int len = min(inlen, 512);
send_packet(ssh, SSH1_CMSG_STDIN_DATA,
PKT_INT, len, PKT_DATA, in, len, PKT_END);
send_packet(ssh, SSH1_CMSG_STDIN_DATA, PKTT_DATA,
PKT_INT, len, PKT_DATA, in, len,
PKTT_OTHER, PKT_END);
in += len;
inlen -= len;
}
@ -4573,8 +4708,10 @@ static int ssh2_try_send(struct ssh_channel *c)
len = c->v.v2.remmaxpkt;
ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
ssh2_pkt_adduint32(ssh, c->remoteid);
dont_log_data(ssh, PKTLOG_OMIT);
ssh2_pkt_addstring_start(ssh);
ssh2_pkt_addstring_data(ssh, data, len);
end_log_omission(ssh);
ssh2_pkt_send(ssh);
bufchain_consume(&c->v.v2.outbuffer, len);
c->v.v2.remwindow -= len;
@ -5385,8 +5522,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
ssh2_pkt_addstring(ssh, "password");
ssh2_pkt_addbool(ssh, FALSE);
dont_log_password(ssh, PKTLOG_BLANK);
ssh2_pkt_addstring(ssh, s->password);
memset(s->password, 0, sizeof(s->password));
end_log_omission(ssh);
ssh2_pkt_defer(ssh);
/*
* We'll include a string that's an exact multiple of the
@ -5430,8 +5569,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
ssh2_pkt_adduint32(ssh, s->num_prompts);
}
if (s->need_pw) { /* only add pw if we just got one! */
dont_log_password(ssh, PKTLOG_BLANK);
ssh2_pkt_addstring(ssh, s->password);
memset(s->password, 0, sizeof(s->password));
end_log_omission(ssh);
s->curr_prompt++;
}
if (s->curr_prompt >= s->num_prompts) {
@ -6412,6 +6553,9 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
ssh->deferred_send_data = NULL;
ssh->deferred_len = 0;
ssh->deferred_size = 0;
ssh->pktout_logmode = PKTLOG_EMIT;
ssh->pktout_nblanks = 0;
ssh->pktout_blanks = NULL;
ssh->fallback_cmd = 0;
ssh->pkt_ctx = 0;
ssh->x11auth = NULL;