Initial commit

1 files changed, 273 insertions, 0 deletions

diff --git a/src/minidentd/minidentd.c b/src/minidentd/minidentd.c
new file mode 100644
index 0000000..0bd86be
--- /dev/null
+++ b/src/minidentd/minidentd.c
@@ -0,0 +1,273 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <errno.h>
+#include <pwd.h>
+#include <skalibs/uint16.h>
+#include <skalibs/uint32.h>
+#include <skalibs/uint.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/fmtscan.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/tai.h>
+#include <skalibs/random.h>
+#include <skalibs/unix-timed.h>
+#include "mgetuid.h"
+
+#define USAGE "minidentd [ -v ] [ -n | -i | -r ] [ -y file ] [ -t timeout ]"
+#define dieusage() strerr_dieusage(100, USAGE)
+
+
+static int how = 0 ;
+static int flagverbose = 0 ;
+static char const *userfile = ".ident" ;
+
+static tain_t deadline ;
+static unsigned int nquery = 0 ;
+static char logfmt[UINT_FMT] ;
+
+#define DECIMAL "0123456789"
+#define godecimal(s) while (*(s) && !DECIMAL[str_chr(DECIMAL, *(s))]) (s)++
+
+static int parseline (char const *s, uint16 *localport, uint16 *remoteport)
+{
+  unsigned int pos = 0 ;
+
+  godecimal(s) ;
+  if (!*s) return 0 ;
+  s += uint16_scan(s, localport) ;
+  if (!*s) return 0 ;
+  s += str_chr(s+pos, ',') ;
+  if (*s) s++ ;
+  godecimal(s) ;
+  if (!*s) return 0 ;
+  if (!uint16_scan(s, remoteport)) return 0 ;
+  return 1 ;
+}
+
+static void formatlr (char *s, uint16 lp, uint16 rp)
+{
+  s += uint16_fmt(s, lp) ;
+  *s++ = ',' ;
+  *s++ = ' ' ;
+  s += uint16_fmt(s, rp) ;
+  *s = 0 ;
+}
+
+static void reply (char const *s, char const *r, char const *info)
+{
+  buffer_puts(buffer_1small, s) ;
+  buffer_put(buffer_1small, " : ", 3) ;
+  buffer_puts(buffer_1small, r) ;
+  buffer_put(buffer_1small, " : ", 3) ;
+  buffer_puts(buffer_1small, info) ;
+  buffer_put(buffer_1small, "\r\n", 2) ;
+  if (!buffer_timed_flush_g(buffer_1small, &deadline))
+    strerr_diefu1sys(111, "write to stdout") ;
+}
+
+static void logquery (char const *s)
+{
+  if (!flagverbose) return ;
+  logfmt[uint_fmt(logfmt, ++nquery)] = 0 ;
+  buffer_put(buffer_2, "query ", 6) ;
+  buffer_puts(buffer_2, logfmt) ;
+  buffer_put(buffer_2, ": ", 2) ;
+  buffer_puts(buffer_2, s) ;
+  buffer_putflush(buffer_2, "\n", 1) ;
+}
+
+static void logreply (char const *type, char const *reply1, char const *reply2)
+{
+  if (!flagverbose) return ;
+  buffer_puts(buffer_2, "reply type ") ;
+  buffer_puts(buffer_2, type) ;
+  buffer_put(buffer_2, ": ", 2) ;
+  buffer_puts(buffer_2, logfmt) ;
+  buffer_put(buffer_2, ": ", 2) ;
+  buffer_puts(buffer_2, reply1) ;
+  buffer_put(buffer_2, ": ", 2) ;
+  buffer_puts(buffer_2, reply2) ;
+  buffer_putflush(buffer_2, "\n", 1) ;
+}
+
+static int userident (char *s, char const *home)
+{
+  int fd ;
+  int r = 1 ;
+  {
+    unsigned int homelen = str_len(home) ;
+    unsigned int userlen = str_len(userfile) ;
+    char tmp[homelen + userlen + 2] ;
+    byte_copy(tmp, homelen, home) ;
+    tmp[homelen] = '/' ;
+    byte_copy(tmp + homelen + 1, userlen + 1, userfile) ;
+    fd = open_readb(tmp) ;
+  }  
+  if (fd == -1) return (errno != ENOENT) ? -1 : 0 ;
+  if (how == 1)
+  {
+    fd_close(fd) ;
+    return 1 ;
+  }
+  r = allread(fd, s, 14) ;
+  fd_close(fd) ;
+  if (r == -1) return -1 ;
+  if (!r) return 1 ;
+  s[r] = 0 ;
+  s[byte_chr(s, r, '\n')] = 0 ;
+  return 2 ;
+}
+
+
+static void doit (char const *s, ip46_t const *localaddr, ip46_t const *remoteaddr)
+{
+  char lr[15] ;
+  uint16 localport, remoteport ;
+  struct passwd *pw ;
+  int uid ;
+  if (!parseline(s, &localport, &remoteport))
+  {
+    reply("0, 0", "ERROR", "INVALID-PORT") ;
+    return ;
+  }
+  formatlr(lr, localport, remoteport) ;
+  logquery(lr) ;
+
+  uid = mgetuid(localaddr, localport, remoteaddr, remoteport) ;
+  if (uid == -2)
+  {
+    strerr_warnwu1sys("get uid") ;
+    reply(lr, "ERROR", "UNKNOWN-ERROR") ;
+    return ;
+  }
+  else if (uid == -1)
+  {
+    reply(lr, "ERROR", "NO-USER") ;
+    logreply("error", "ERROR", "NO-USER") ;
+    return ;
+  }
+
+  if (how == 3)                                                              
+  {                                                                            
+    char name[9] ;                                                             
+    char fmt[4 + UINT_FMT] = "uid " ;                                                    
+    fmt[4 + uint_fmt(fmt+4, uid)] = 0 ;                                      
+    if (random_name(name, 8) < 8)                                                       
+    {                                                                          
+      strerr_warnwu1sys("perform random") ;                                    
+      reply(lr, "ERROR", "UNKNOWN-ERROR") ;                                    
+      return ;                                                                 
+    }                                                                          
+    reply(lr, "UNIX", name) ;                                                  
+    logreply("random", fmt, name) ;                                            
+    return ;                                                                   
+  }                                            
+
+  pw = getpwuid(uid) ;
+  if (!pw)
+  {
+    char fmt[UINT_FMT] ;
+    fmt[uint_fmt(fmt, uid)] = 0 ;
+    strerr_warnw2x("unknown uid ", fmt) ;
+    reply(lr, "ERROR", "UNKNOWN-ERROR") ;
+    return ;
+  }
+
+  if (how)
+  {
+    char s[15] ;
+    register int r = userident(s, pw->pw_dir) ;
+    if ((how == 1) || (r == 1))
+    {
+      reply(lr, "ERROR", "HIDDEN-USER") ;
+      logreply("user", "ERROR", "HIDDEN-USER") ;
+      return ;
+    }
+    else if (r == 2)
+    {
+      reply(lr, "USERID : UNIX", s) ;
+      logreply("user", "UNIX", s) ;
+      return ;
+    }
+  }
+
+  reply(lr, "USERID : UNIX", pw->pw_name) ;
+  logreply("user", "UNIX", pw->pw_name) ;
+}
+
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  stralloc line = STRALLOC_ZERO ;
+  tain_t tto ;
+  ip46_t localaddr, remoteaddr ;
+  PROG = "minidentd" ;
+
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    unsigned int t = 0 ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "vniry:t:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'v' : flagverbose = 1 ; break ;
+        case 'n' : how = 1 ; break ;
+        case 'i' : how = 2 ; break ;
+        case 'r' : how = 3 ; break ;
+        case 'y' : userfile = l.arg ; break ;
+        case 't' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
+        default : dieusage() ;
+      }
+    }
+    if (t) tain_from_millisecs(&tto, t) ; else tto = tain_infinite_relative ;
+    argc -= l.ind ; argv += l.ind ;
+  }
+
+  {
+    char const *proto = env_get2(envp, "PROTO") ;
+    if (!proto) strerr_dienotset(100, "PROTO") ;
+    {
+      char const *x ;
+      unsigned int protolen = str_len(proto) ;
+      char tmp[protolen + 9] ;
+      byte_copy(tmp, protolen, proto) ;
+      byte_copy(tmp + protolen, 8, "LOCALIP") ;
+      x = env_get2(envp, tmp) ;
+      if (!x) strerr_dienotset(100, tmp) ;
+      if (!ip46_scan(x, &localaddr)) strerr_dieinvalid(100, tmp) ;
+      byte_copy(tmp + protolen, 9, "REMOTEIP") ;
+      x = env_get2(envp, tmp) ;
+      if (!x) strerr_dienotset(100, tmp) ;
+      if (!ip46_scan(x, &remoteaddr)) strerr_dieinvalid(100, tmp) ;
+    }
+  }
+
+  if (ip46_is6(&localaddr) != ip46_is6(&remoteaddr))
+    strerr_dief1x(100, "local and remote address not of the same family") ;
+  tain_now_g() ;
+                                                                                    
+  for (;;)
+  {
+    register int r ;
+    line.len = 0 ;
+    tain_add_g(&deadline, &tto) ;
+    r = timed_getln_g(buffer_0small, &line, '\n', &deadline) ;
+    if (r == -1)
+    {
+      if (errno == ETIMEDOUT) return 1 ;
+      else strerr_diefu1sys(111, "read from stdin") ;
+    }
+    if (!r) break ;
+    line.s[line.len - 1] = 0 ;
+    doit(line.s, &localaddr, &remoteaddr) ;
+  }
+  return 0 ;
+}