csauth.c revision 3f54fd611f536639ec30dd53c48e5ec1897cc7d9
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1990-2012 AT&T Intellectual Property *
* and is licensed under the *
* Eclipse Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.eclipse.org/org/documents/epl-v10.html *
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Glenn Fowler
* AT&T Research
*
* authenticate fd given service authentication path
* if path==0 then it is requested from server
* otherwise if fd>=0 then state->host and state->flags are assumed valid
* only used by tcp streams
* fd<0 for remote authentication on fd 0,1
*
* csauth(state,fd,path,arg) called by csopen()
* csauth(state,-1,path,arg) called by `cs -O...'
* csauth(state,fd,0,arg) normal user call
*/
#include "cslib.h"
#include <error.h>
#define AUTH_BASE 1000
int
csauth(register Cs_t* state, int fd, const char* path, const char* arg)
{
register char* s;
register char* t;
char* b;
char* key = 0;
int n;
int m;
int wfd;
unsigned long t1;
unsigned long t2;
struct stat st;
char num[64];
char buf[PATH_MAX + 1];
char tmp[PATH_MAX + 1];
static int auth = -1;
messagef((state->id, NiL, -8, "auth(%d,%s,%s) call", fd, path, arg));
if (!path)
{
if (fd < 0)
goto sorry;
if (!getauth(fd, n))
goto ok;
n = sfsprintf(buf, sizeof(buf), "%d\n", CS_KEY_SEND);
if (cswrite(state, fd, buf, n) != n)
{
messagef((state->id, NiL, -1, "auth: `%-.*s': KEY_SEND write error", n - 1, buf));
goto sorry;
}
if ((n = csread(state, fd, buf, sizeof(buf), CS_LINE)) <= 1)
{
messagef((state->id, NiL, -1, "auth: KEY_SEND read error"));
goto sorry;
}
buf[n - 1] = 0;
path = (const char*)buf;
}
if (stat(path, &st))
{
if (errno == ENOENT)
goto ok;
messagef((state->id, NiL, -1, "auth: %s: stat error", path));
return -1;
}
if (fd < 0)
{
/*
* the remote side of remote authentication
*/
fd = 0;
wfd = 1;
}
else wfd = fd;
m = getpid();
s = tmp + sfsprintf(tmp, sizeof(tmp) - 1, "%lu %d", (unsigned long)st.st_mtime, m);
if ((t = (char*)arg) && !(st.st_mode & S_IXOTH))
{
b = tmp + sizeof(tmp) - 1;
if (s < b)
{
*s++ = ' ';
while (s < b && *t)
if ((*s++ = *t++) == '/' && *t == '#' && *++t != '#')
*(s - 1) = ' ';
}
}
*s++ = '\n';
n = s - tmp;
if (cswrite(state, wfd, tmp, n) != n)
{
messagef((state->id, NiL, -1, "auth: `%-.*s': key write error", n - 1, tmp));
goto sorry;
}
if (csread(state, fd, num, sizeof(num), CS_LINE) <= 0)
{
messagef((state->id, NiL, -1, "auth: key read error"));
goto sorry;
}
if (*num != '\n')
{
n = 0;
if (state->addr == csaddr(state, NiL)) b = tmp + sfsprintf(tmp, sizeof(tmp), "%s/AUTH.%05d.", csvar(state, CS_VAR_LOCAL, 0), m);
else
{
s = (char*)path + strlen(path);
while (s > (char*)path)
if (*--s == '/' && ++n >= 4) break;
if (n != 4) goto sorry;
b = tmp + sfsprintf(tmp, sizeof(tmp), "%-.*s/AUTH.%05d.", s - path, path, m);
}
if (s = strrchr(tmp, '/'))
{
*s = 0;
if (eaccess(tmp, X_OK) && (mkdir(tmp, S_IRWXU|S_IRWXG|S_IRWXO) || chmod(tmp, S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO)))
{
messagef((state->id, NiL, -1, "auth: %s: challenge directory error", tmp));
goto sorry;
}
*s = '/';
}
t1 = CSTIME();
m += t1 + getppid();
t1 -= CS_STAT_DOWN;
if (auth < 0) auth = (unsigned int)CSTOSS(m, 0) % AUTH_BASE;
n = auth;
for (;;)
{
if (++auth >= AUTH_BASE) auth = 0;
if (auth == n)
{
messagef((state->id, NiL, -1, "auth: %s: challenge directory full", tmp));
goto sorry;
}
s = b + sfsprintf(b, sizeof(tmp) - (b - tmp), "%03d", auth);
if ((stat(tmp, &st) || t1 <= (unsigned long)st.st_ctime && !remove(tmp)) && !close(open(tmp, O_CREAT|O_TRUNC|O_cloexec, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH))) break;
}
key = tmp;
if (tokscan(num, NiL, "%lu %lu", &t1, &t2) != 2)
{
messagef((state->id, NiL, -1, "auth: `%s': challenge syntax error", num));
goto sorry;
}
if (cschallenge(state, tmp, &t1, &t2))
goto sorry;
if (chmod(tmp, S_ISUID|S_ISGID|S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH))
{
messagef((state->id, NiL, -1, "auth: %s: challenge chmod error", tmp));
goto sorry;
}
t = s;
if (arg)
{
b = tmp + sizeof(tmp) - 1;
if (s < b)
{
*s++ = ' ';
while (s < b && *arg)
if ((*s++ = *arg++) == '/' && *arg == '#')
{
arg++;
*(s - 1) = ' ';
}
}
}
*s++ = '\n';
n = cswrite(state, wfd, tmp, s - tmp);
*t = 0;
if (n != s - tmp)
{
messagef((state->id, NiL, -1, "auth: `%s': ack write error", tmp));
goto sorry;
}
if (csread(state, fd, num, 1, CS_LINE) != 1)
{
messagef((state->id, NiL, -1, "auth: ack read error"));
goto sorry;
}
if (remove(tmp))
{
messagef((state->id, NiL, -1, "auth: %s: challenge remove error", tmp));
goto sorry;
}
}
if (fd >= 0) setauth(fd, n);
ok:
messagef((state->id, NiL, -8, "auth(%d,%s,%s) = 0", fd, path, arg));
return 0;
sorry:
if (key) remove(key);
errno = EACCES;
return -1;
}
/*
* set up the challenge {v1,v2} on path
*/
int
cschallenge(Cs_t* state, const char* path, unsigned long* v1, unsigned long* v2)
{
struct stat st;
if (touch(path, (time_t)(v1 ? *v1 : cs.time), (time_t)(v2 ? *v2 : cs.time), 0))
{
messagef((state->id, NiL, -1, "auth: %s: challenge touch error", path));
return -1;
}
if (stat(path, &st))
{
messagef((state->id, NiL, -1, "auth: %s: challenge stat error", path));
return -1;
}
if (v1)
*v1 = st.st_atime;
if (v2)
*v2 = st.st_mtime;
return 0;
}
int
_cs_auth(int fd, const char* path, const char* arg)
{
return csauth(&cs, fd, path, arg);
}
int
_cs_challenge(const char* path, unsigned long* v1, unsigned long* v2)
{
return cschallenge(&cs, path, v1, v2);
}