From fd38bd8ad5ddaf5f81887b878dddd212a77113b0 Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Mon, 20 Jul 2015 05:33:26 +0000
Subject:  Always use names linked in scandir

---
 src/s6-rc/s6-rc-init.c   |  2 +-
 src/s6-rc/s6-rc-update.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/s6-rc/s6-rc.c        | 16 ++++----
 3 files changed, 104 insertions(+), 9 deletions(-)

(limited to 'src')

diff --git a/src/s6-rc/s6-rc-init.c b/src/s6-rc/s6-rc-init.c
index b22d399..e34ed18 100644
--- a/src/s6-rc/s6-rc-init.c
+++ b/src/s6-rc/s6-rc-init.c
@@ -220,7 +220,7 @@ int main (int argc, char const *const *argv)
       unsigned int i = 0 ;
       int r ;
       uint16 ids[ndirs] ;
-      char srcfn[llen + 23 + maxlen] ;
+      char srcfn[llen + 23 + maxlen] ; /* XXX: unsafe is dir is writable by non-root */
       char dstfn[llen + 9 + sizeof(S6_SVSCAN_CTLDIR "/control") + maxlen] ;
       rewinddir(dir) ;
       byte_copy(srcfn, llen + 12, lfn) ;
diff --git a/src/s6-rc/s6-rc-update.c b/src/s6-rc/s6-rc-update.c
index 89db68e..a146c99 100644
--- a/src/s6-rc/s6-rc-update.c
+++ b/src/s6-rc/s6-rc-update.c
@@ -1,11 +1,106 @@
 /* ISC license. */
 
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <skalibs/bytestr.h>
 #include <skalibs/sgetopt.h>
 #include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+#include <s6/s6-supervise.h>
+#include <s6-rc/s6rc-constants.h>
 
 #define USAGE "s6-rc-update [ -l live ]"
 #define dieusage() strerr_dieusage(100, USAGE)
 
+static char const *live = S6RC_LIVE_BASE ;
+
+static int safe_servicedir_update (char const *dst, char const *src, int h)
+{
+  unsigned int dstlen = str_len(dst) ;
+  unsigned int srclen = str_len(src) ;
+  int fd ;
+  int hasdata = 1, hasenv = 1, ok = 1 ;
+  char dstfn[dstlen + 15 + sizeof(S6_SUPERVISE_CTLDIR)] ;
+  char srcfn[srclen + 17] ;
+  char tmpfn[dstlen + 21] ;
+  byte_copy(dstfn, dstlen, dst) ;
+  byte_copy(srcfn, srclen, src) ;
+
+  byte_copy(dstfn + dstlen, 6, "/down") ;
+  fd = open_trunc(dstfn) ;
+  if (fd < 0) strerr_warnwu2sys("touch ", dstfn) ;
+  else close(fd) ;
+  byte_copy(dstfn + dstlen + 1, 5, "data") ;
+  byte_copy(tmpfn, dstlen + 5, dstfn) ;
+  byte_copy(tmpfn + dstlen + 5, 5, ".old") ;
+  if (rename(dstfn, tmpfn) < 0)
+  {
+    if (errno == ENOENT) hasdata = 0 ;
+    else goto err ;
+  }
+  byte_copy(dstfn + dstlen + 1, 4, "env") ;
+  byte_copy(tmpfn + dstlen + 1, 8, "env.old") ;
+  if (rename(dstfn, tmpfn) < 0)
+  {
+    if (errno == ENOENT) hasenv = 0 ;
+    else goto err ;
+  }
+  byte_copy(dstfn + dstlen + 1, 9, "nosetsid") ;
+  if (unlink(dstfn) < 0 && errno != ENOENT) goto err ;
+  byte_copy(dstfn + dstlen + 3, 14, "tification-fd") ;
+  if (unlink(dstfn) < 0 && errno != ENOENT) goto err ;
+
+  byte_copy(srcfn + srclen, 17, "/notification-fd") ;
+  hiercopy(srcfn, dstfn) ;
+  byte_copy(srcfn + srclen + 3, 7, "setsid") ;
+  byte_copy(dstfn + dstlen + 3, 7, "setsid") ;
+  hiercopy(srcfn, dstfn) ;
+  byte_copy(srcfn + srclen + 1, 5, "data") ;
+  byte_copy(dstfn + dstlen + 1, 5, "data") ;
+  hiercopy(srcfn, dstfn) ;
+  byte_copy(srcfn + srclen + 1, 4, "env") ;
+  byte_copy(dstfn + dstlen + 1, 4, "env") ;
+  hiercopy(srcfn, dstfn) ;
+  byte_copy(srcfn + srclen + 1, 4, "run") ;
+  byte_copy(dstfn + dstlen + 1, 4, "run") ;
+  if (!hiercopy(srcfn, dstfn)) goto err ;
+  byte_copy(srcfn + srclen + 1, 4, "run") ;
+  byte_copy(dstfn + dstlen + 1, 4, "finish") ;
+  hiercopy(srcfn, dstfn) ;
+  if (h)
+  {
+    byte_copy(dstfn + dstlen + 1, 5, "down") ;
+    if (unlink(dstfn) < 0)
+    {
+      strerr_warnwu2sys("unlink ", dstfn) ;
+      ok = 0 ;
+    }
+    byte_copy(dstfn + dstlen + 1, 8 + sizeof(S6_SUPERVISE_CTLDIR), S6_SUPERVISE_CTLDIR "/control") ;
+    s6_svc_write(dstfn, "u", 1) ;
+  }
+  byte_copy(dstfn + dstlen + 1, 9, "data.old") ;
+  rm_rf(dstfn) ;
+  byte_copy(dstfn + dstlen + 1, 8, "env.old") ;
+  rm_rf(dstfn) ;
+  return 1 ;
+
+ err:
+  if (h)
+  {
+    int e = errno ;
+    byte_copy(dstfn + dstlen + 1, 5, "down") ;
+    unlink(dstfn) ;
+    errno = e ;
+  }
+  return 0 ;
+}
+
+static int servicedir_name_change (char const *live, char const *oldname, char const *newname)
+{
+  return 1 ;
+} 
+
 int main (int argc, char const *const *argv)
 {
   PROG = "s6-rc-update" ;
diff --git a/src/s6-rc/s6-rc.c b/src/s6-rc/s6-rc.c
index 2190404..bd5011c 100644
--- a/src/s6-rc/s6-rc.c
+++ b/src/s6-rc/s6-rc.c
@@ -112,14 +112,14 @@ static pid_t start_longrun (unsigned int i, int h)
   unsigned int m = 0 ;
   char fmt[UINT32_FMT] ;
   char vfmt[UINT_FMT] ;
-  char servicefn[livelen + svdlen + 30] ;
+  char servicefn[livelen + svdlen + 26] ;
   char const *newargv[7 + !!dryrun[0] * 6] ;
   byte_copy(servicefn, livelen, live) ;
-  byte_copy(servicefn + livelen, 13, "/servicedirs/") ;
-  byte_copy(servicefn + livelen + 13, svdlen, db->string + db->services[i].x.longrun.servicedir) ;
+  byte_copy(servicefn + livelen, 9, "/scandir/") ;
+  byte_copy(servicefn + livelen + 9, svdlen, db->string + db->services[i].x.longrun.servicedir) ;
   if (h)
   {
-    byte_copy(servicefn + livelen + 13 + svdlen, 17, "/notification-fd") ;
+    byte_copy(servicefn + livelen + 9 + svdlen, 17, "/notification-fd") ;
     if (access(servicefn, F_OK) < 0)
     {
       h = 2 ;
@@ -154,11 +154,11 @@ static void success_longrun (unsigned int i, int h)
   if (!dryrun[0])
   {
     unsigned int svdlen = str_len(db->string + db->services[i].x.longrun.servicedir) ;
-    char fn[livelen + svdlen + 19] ;
+    char fn[livelen + svdlen + 15] ;
     byte_copy(fn, livelen, live) ;
-    byte_copy(fn + livelen, 13, "/servicedirs/") ;
-    byte_copy(fn + livelen + 13, svdlen, db->string + db->services[i].x.longrun.servicedir) ;
-    byte_copy(fn + livelen + 13 + svdlen, 6, "/down") ;
+    byte_copy(fn + livelen, 9, "/scandir/") ;
+    byte_copy(fn + livelen + 9, svdlen, db->string + db->services[i].x.longrun.servicedir) ;
+    byte_copy(fn + livelen + 9 + svdlen, 6, "/down") ;
     if (h)
     {
       if (unlink(fn) < 0 && verbosity)
-- 
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