X-Git-Url: https://git.saurik.com/apt.git/blobdiff_plain/9983999d294887046abf386adc31190700d89b61..e8afd16892e87a6e2f17c1019ee455f5583387c2:/apt-pkg/contrib/fileutl.cc

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index f6351b7b5..8ec868ec0 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -800,8 +800,9 @@ pid_t ExecFork(std::set<int> KeepFDs)
       signal(SIGCONT,SIG_DFL);
       signal(SIGTSTP,SIG_DFL);
 
+      long ScOpenMax = sysconf(_SC_OPEN_MAX);
       // Close all of our FDs - just in case
-      for (int K = 3; K != sysconf(_SC_OPEN_MAX); K++)
+      for (int K = 3; K != ScOpenMax; K++)
       {
 	 if(KeepFDs.find(K) == KeepFDs.end())
 	    fcntl(K,F_SETFD,FD_CLOEXEC);
@@ -874,6 +875,25 @@ bool StartsWithGPGClearTextSignature(string const &FileName)
    return true;
 }
 									/*}}}*/
+// ChangeOwnerAndPermissionOfFile - set file attributes to requested values /*{{{*/
+bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * const file, char const * const user, char const * const group, mode_t const mode)
+{
+   if (strcmp(file, "/dev/null") == 0)
+      return true;
+   bool Res = true;
+   if (getuid() == 0 && strlen(user) != 0 && strlen(group) != 0) // if we aren't root, we can't chown, so don't try it
+   {
+      // ensure the file is owned by root and has good permissions
+      struct passwd const * const pw = getpwnam(user);
+      struct group const * const gr = getgrnam(group);
+      if (pw != NULL && gr != NULL && chown(file, pw->pw_uid, gr->gr_gid) != 0)
+	 Res &= _error->WarningE(requester, "chown to %s:%s of file %s failed", user, group, file);
+   }
+   if (chmod(file, mode) != 0)
+      Res &= _error->WarningE(requester, "chmod 0%o of file %s failed", mode, file);
+   return Res;
+}
+									/*}}}*/
 
 class FileFdPrivate {							/*{{{*/
 	public:
@@ -2066,9 +2086,11 @@ std::string GetTempDir()						/*{{{*/
       tmpdir = P_tmpdir;
 #endif
 
-   // check that tmpdir is set and exists
    struct stat st;
-   if (!tmpdir || strlen(tmpdir) == 0 || stat(tmpdir, &st) != 0)
+   if (!tmpdir || strlen(tmpdir) == 0 || // tmpdir is set
+	 stat(tmpdir, &st) != 0 || (st.st_mode & S_IFDIR) == 0 || // exists and is directory
+	 access(tmpdir, R_OK | W_OK | X_OK) != 0 // current user has rwx access to directory
+      )
       tmpdir = "/tmp";
 
    return string(tmpdir);
@@ -2168,12 +2190,6 @@ bool DropPrivileges()							/*{{{*/
    if(_config->FindB("Debug::NoDropPrivs", false) == true)
       return true;
 
-   // empty setting disables DropPrivilidges - this also ensures
-   // backward compatibility, see bug #764506
-   const std::string toUser = _config->Find("APT::Sandbox::User");
-   if (toUser.empty())
-      return true;
-
 #if __gnu_linux__
 #if defined(PR_SET_NO_NEW_PRIVS) && ( PR_SET_NO_NEW_PRIVS != 38 )
 #error "PR_SET_NO_NEW_PRIVS is defined, but with a different value than expected!"
@@ -2185,6 +2201,12 @@ bool DropPrivileges()							/*{{{*/
       _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret);
 #endif
 
+   // empty setting disables privilege dropping - this also ensures
+   // backward compatibility, see bug #764506
+   const std::string toUser = _config->Find("APT::Sandbox::User");
+   if (toUser.empty())
+      return true;
+
    // uid will be 0 in the end, but gid might be different anyway
    uid_t const old_uid = getuid();
    gid_t const old_gid = getgid();