2.11BSD/src/libexec/identd/src/kernel/svr4.c
/*
** kernel/svr4.c SVR4 specific kernel access functions
**
** This program is in the public domain and may be used freely by anyone
** who wants to.
**
** Last update: 17 March 1993
**
** Please send bug fixes/bug reports to: Peter Eriksson <pen@lysator.liu.se>
*/
#define STRNET
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <nlist.h>
#include <pwd.h>
#include <signal.h>
#include <syslog.h>
# include "kvm.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#define KERNEL
#include <sys/file.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/fcntl.h>
#include <sys/stream.h>
#include <sys/stat.h>
#include <sys/cred.h>
#include <sys/vnode.h>
#include <sys/mkdev.h>
#define ucred cred
#include <sys/wait.h>
#undef KERNEL
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#ifndef ATTSVR4
#include <netinet/in_pcb.h>
#endif
#include <netinet/tcp.h>
#include <netinet/ip_var.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <arpa/inet.h>
#include "identd.h"
#include "error.h"
extern void *calloc();
extern void *malloc();
struct nlist nl[] =
{
#ifndef ATTSVR4
#define N_FILE 0
#define N_TCB 1
{ "file" },
{ "tcb" },
#else /* AT&T's hacked version below */
#define N_FILE 0
#define N_TCPD 1
#define N_TCPD_CNT 2
{ "file" },
{ "tcpd" },
{ "tcpd_cnt" },
#endif /* ATTSVR4 */
{ "" }
};
static kvm_t *kd;
#ifndef ATTSVR4
static struct inpcb tcb;
#endif
#ifdef ATTSVR4
static struct tcpd tcpd; /* we will read this one at a time */
static int tcpd_cnt; /* # of tcpd's we have */
#endif
int k_open()
{
/*
** Open the kernel memory device
*/
if (!(kd = kvm_open(path_unix, path_kmem, NULL, O_RDONLY, NULL)))
ERROR("main: kvm_open");
/*
** Extract offsets to the needed variables in the kernel
*/
if (kvm_nlist(kd, nl) != 0)
ERROR("main: kvm_nlist");
return 0;
}
/*
** Get a piece of kernel memory with error handling.
** Returns 1 if call succeeded, else 0 (zero).
*/
static int getbuf(addr, buf, len, what)
long addr;
char *buf;
int len;
char *what;
{
if (kvm_read(kd, addr, buf, len) < 0)
{
if (syslog_flag)
syslog(LOG_ERR, "getbuf: kvm_read(%08x, %d) - %s : %m",
addr, len, what);
return 0;
}
return 1;
}
/*
** Traverse the inpcb list until a match is found.
** Returns NULL if no match.
*/
static short
getlist(pcbp, faddr, fport, laddr, lport)
#ifdef ATTSVR4
struct tcpd *pcbp;
#else
struct inpcb *pcbp;
#endif
struct in_addr *faddr;
int fport;
struct in_addr *laddr;
int lport;
{
#ifdef ATTSVR4
struct tcpcb *head;
struct tcpcb tcpcb;
int i;
int address_of_tcpcb;
#else
struct inpcb *head;
#endif
if (!pcbp)
return -1;
#ifdef ATTSVR4
i = 0; /* because we have already read 1 we inc later of the struct */
do
{
/* don't ask be why (HACK) but the forth element that td_tcpcb
** points to contains the address of the tcpcb
** the struct is struct msgb which is a bunch of pointers
** to arrays (in <sys/stream.h> and the fouth element of the
** struct seems to always have the address...there is no comments
** in the .h files to indict why this is, and since I don't have
** source I don't know why....I found this info using crash looking
** around the structure tcpd, using the command 'od -x address count'
**
** I assume that this would change....but it seems to work on AT&T SVR4.0
** Rel. 2.1
**
** Bradley E. Smith <brad@bradley.bradley.edu>
*/
if (!getbuf( (long) pcbp->td_tcpcb + (3 * sizeof(int)),
&address_of_tcpcb, sizeof(int), "&address_of_tcpcb") )
{
return -1;
}
if (!getbuf( address_of_tcpcb, &tcpcb, sizeof(tcpcb) , "&tcpcb"))
{
return -1;
}
i++; /* for the read */
if (!tcpcb.t_laddr || !tcpcb.t_faddr) /* skip unused entrys */
continue;
/* have to convert these babies */
if ( tcpcb.t_faddr == htonl(faddr->s_addr) &&
tcpcb.t_laddr == htonl(laddr->s_addr) &&
tcpcb.t_fport == htons(fport) &&
tcpcb.t_lport == htons(lport) )
return pcbp->td_dev;
/* if we get here we need to read the tcpd followed by tcpcb, but
** first we check if we are at the end of the tcpd struct
*/
} while ( (i != tcpd_cnt) &&
getbuf((long) (nl[N_TCPD].n_value + ( i * sizeof(struct tcpd)) ),
pcbp, sizeof(struct tcpd), "tcpdlist") );
#else
head = pcbp->inp_prev;
do
{
if ( pcbp->inp_faddr.s_addr == faddr->s_addr &&
pcbp->inp_laddr.s_addr == laddr->s_addr &&
pcbp->inp_fport == fport &&
pcbp->inp_lport == lport )
return pcbp->inp_minor;
} while (pcbp->inp_next != head &&
getbuf((long) pcbp->inp_next,
pcbp,
sizeof(struct inpcb),
"tcblist"));
#endif /* not ATTSVR4 */
return -1;
}
/*
** Return the user number for the connection owner in the int pointed
** at in the uid argument.
*/
int k_getuid(faddr, fport, laddr, lport, uid)
struct in_addr *faddr;
int fport;
struct in_addr *laddr;
int lport;
int *uid;
{
long addr;
struct stat s;
short tcpmajor; /* Major number of the tcp device */
short sockp; /* Really a device minor number */
struct file *filehead, file;
struct ucred ucb;
/* -------------------- FILE DESCRIPTOR TABLE -------------------- */
if (!getbuf(nl[N_FILE].n_value, &addr, sizeof(addr), "&file"))
return -1;
/* we just need to determine the major number of the tcp module, which
is the minor number of the tcp clone device /dev/tcp */
if (stat("/dev/tcp", &s))
ERROR("stat(\"/dev/tcp\")");
tcpmajor = minor(s.st_rdev);
/* -------------------- TCP PCB LIST -------------------- */
#ifdef ATTSVR4
/* get the number of tcpd structs together */
if (!getbuf(nl[N_TCPD_CNT].n_value, &tcpd_cnt,
sizeof(tcpd_cnt), "&tcpd_cnt"))
return -1;
if (!getbuf(nl[N_TCPD].n_value, &tcpd, sizeof(tcpd), "&tcpd"))
return -1;
sockp = getlist(&tcpd, faddr, fport, laddr, lport);
#else
if (!getbuf(nl[N_TCB].n_value, &tcb, sizeof(tcb), "tcb"))
return -1;
tcb.inp_prev = (struct inpcb *) nl[N_TCB].n_value;
sockp = getlist(&tcb, faddr, fport, laddr, lport);
#endif
if (sockp < 0)
return -1;
/*
* Get the pointer to the head of the file list
*/
if (!getbuf(nl[N_FILE].n_value, &filehead, sizeof(struct file *)))
return -1;
file.f_next = filehead;
do
{
struct vnode vnode;
/*
** Grab a file record
*/
if (!getbuf((long)file.f_next, &file, sizeof(struct file), "file"))
return -1;
/*
** Grab the vnode information to check whether this file is the
** correct major & minor char device
*/
if (!getbuf((off_t)file.f_vnode, &vnode, sizeof(struct vnode), "vnode"))
return -1;
if ((vnode.v_type == VCHR) && (major(vnode.v_rdev) == tcpmajor) &&
(minor(vnode.v_rdev) == sockp))
{
/*
** We've found it!
*/
if (!getbuf((off_t)file.f_cred, &ucb, sizeof(struct cred), "cred"))
return -1;
*uid = ucb.cr_ruid;
return 0;
}
} while (file.f_next != filehead);
return -1;
}