Merge branch 'debian/jessie' into debian/experimental

[apt.git] / apt-pkg / contrib / fileutl.cc

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index de67a94b9cce9db491310268315968371a216af6..afc243b7f7dfe8442a8ddd68f0b2165979df3d72 100644 (file)
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -857,11 +857,7 @@ bool ExecWait(pid_t Pid,const char *Name,bool Reap)
    return true;
 }
                                                                        /*}}}*/
    return true;
 }
                                                                        /*}}}*/

-
-
-// StartsWithGPGClearTextSignature - Check if a file is Pgp/GPG clearsigned     /*{{{*/
-// ---------------------------------------------------------------------
-/* */
+// StartsWithGPGClearTextSignature - Check if a file is Pgp/GPG clearsigned    /*{{{*/

 bool StartsWithGPGClearTextSignature(string const &FileName)
 {
    static const char* SIGMSG = "-----BEGIN PGP SIGNED MESSAGE-----\n";
 bool StartsWithGPGClearTextSignature(string const &FileName)
 {
    static const char* SIGMSG = "-----BEGIN PGP SIGNED MESSAGE-----\n";


@@ -877,7 +873,26 @@ bool StartsWithGPGClearTextSignature(string const &FileName)
 
    return true;
 }
 
    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:
 
 class FileFdPrivate {                                                  /*{{{*/
        public:


@@ -896,7 +911,7 @@ class FileFdPrivate {                                                       /*{{{*/
           bool eof;
           bool compressing;
 
           bool eof;
           bool compressing;
 

-          LZMAFILE() : file(NULL), eof(false), compressing(false) {}
+          LZMAFILE() : file(NULL), eof(false), compressing(false) { buffer[0] = '\0'; }

           ~LZMAFILE() {
              if (compressing == true)
              {
           ~LZMAFILE() {
              if (compressing == true)
              {


@@ -1525,7 +1540,7 @@ bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual)
            int err;
            char const * const errmsg = BZ2_bzerror(d->bz2, &err);
            if (err != BZ_IO_ERROR)
            int err;
            char const * const errmsg = BZ2_bzerror(d->bz2, &err);
            if (err != BZ_IO_ERROR)

-              return FileFdError("BZ2_bzread: %s (%d: %s)", _("Read error"), err, errmsg);
+              return FileFdError("BZ2_bzread: %s %s (%d: %s)", FileName.c_str(), _("Read error"), err, errmsg);

         }
 #endif
 #ifdef HAVE_LZMA
         }
 #endif
 #ifdef HAVE_LZMA


@@ -2035,10 +2050,7 @@ APT_DEPRECATED gzFile FileFd::gzFd() {
 #endif
 }
 
 #endif
 }
 

-
-// Glob - wrapper around "glob()"                                      /*{{{*/
-// ---------------------------------------------------------------------
-/* */
+// Glob - wrapper around "glob()"                                      /*{{{*/

 std::vector<std::string> Glob(std::string const &pattern, int flags)
 {
    std::vector<std::string> result;
 std::vector<std::string> Glob(std::string const &pattern, int flags)
 {
    std::vector<std::string> result;


@@ -2064,8 +2076,7 @@ std::vector<std::string> Glob(std::string const &pattern, int flags)
    return result;
 }
                                                                        /*}}}*/
    return result;
 }
                                                                        /*}}}*/

-
-std::string GetTempDir()
+std::string GetTempDir()                                               /*{{{*/

 {
    const char *tmpdir = getenv("TMPDIR");
 
 {
    const char *tmpdir = getenv("TMPDIR");
 


@@ -2074,15 +2085,17 @@ std::string GetTempDir()
       tmpdir = P_tmpdir;
 #endif
 
       tmpdir = P_tmpdir;
 #endif
 

-   // check that tmpdir is set and exists

    struct stat st;
    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);
 }
       tmpdir = "/tmp";
 
    return string(tmpdir);
 }

-
-FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink)
+                                                                       /*}}}*/
+FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink)   /*{{{*/

 {
    char fn[512];
    FileFd *Fd = new FileFd();
 {
    char fn[512];
    FileFd *Fd = new FileFd();


@@ -2106,19 +2119,19 @@ FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink)
 
    return Fd;
 }
 
    return Fd;
 }

-
-bool Rename(std::string From, std::string To)
+                                                                       /*}}}*/
+bool Rename(std::string From, std::string To)                          /*{{{*/

 {
    if (rename(From.c_str(),To.c_str()) != 0)
    {
       _error->Error(_("rename failed, %s (%s -> %s)."),strerror(errno),
                     From.c_str(),To.c_str());
       return false;
 {
    if (rename(From.c_str(),To.c_str()) != 0)
    {
       _error->Error(_("rename failed, %s (%s -> %s)."),strerror(errno),
                     From.c_str(),To.c_str());
       return false;

-   }   
+   }

    return true;
 }
    return true;
 }

-
-bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode)
+                                                                       /*}}}*/
+bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode)/*{{{*/

 {
    int fd;
    if (Mode != FileFd::ReadOnly && Mode != FileFd::WriteOnly)
 {
    int fd;
    if (Mode != FileFd::ReadOnly && Mode != FileFd::WriteOnly)


@@ -2126,10 +2139,8 @@ bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode)
 
    int Pipe[2] = {-1, -1};
    if(pipe(Pipe) != 0)
 
    int Pipe[2] = {-1, -1};
    if(pipe(Pipe) != 0)

-   {

       return _error->Errno("pipe", _("Failed to create subprocess IPC"));
       return _error->Errno("pipe", _("Failed to create subprocess IPC"));

-      return NULL;
-   }
+

    std::set<int> keep_fds;
    keep_fds.insert(Pipe[0]);
    keep_fds.insert(Pipe[1]);
    std::set<int> keep_fds;
    keep_fds.insert(Pipe[0]);
    keep_fds.insert(Pipe[1]);


@@ -2172,47 +2183,104 @@ bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode)
 
    return true;
 }
 
    return true;
 }

-
-bool DropPrivs()
+                                                                       /*}}}*/
+bool DropPrivileges()                                                  /*{{{*/

 {
 {

-   if (getuid() != 0)
-      return true;
-

    if(_config->FindB("Debug::NoDropPrivs", false) == true)
       return true;
 
    if(_config->FindB("Debug::NoDropPrivs", false) == true)
       return true;
 

-   const std::string nobody = _config->Find("APT::User::Nobody", "Debian-apt");
-   struct passwd *pw = getpwnam(nobody.c_str());
-   if (pw == NULL)
-      return _error->Warning("No user %s, can not drop rights", nobody.c_str());
-

 #if __gnu_linux__
 #if __gnu_linux__

-   // see prctl(2), needs linux3.5
-   int ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0,0, 0);
-   if(ret < 0)
+#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!"
+#endif
+   // see prctl(2), needs linux3.5 at runtime - magic constant to avoid it at buildtime
+   int ret = prctl(38, 1, 0, 0, 0);
+   // ignore EINVAL - kernel is too old to understand the option
+   if(ret < 0 && errno != EINVAL)

       _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret);
 #endif
 
       _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret);
 #endif
 

-   if (setgroups(1, &pw->pw_gid) != 1)
+   // 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();
+
+   if (old_uid != 0)
+      return true;
+
+   struct passwd *pw = getpwnam(toUser.c_str());
+   if (pw == NULL)
+      return _error->Error("No user %s, can not drop rights", toUser.c_str());
+
+   // Do not change the order here, it might break things
+   if (setgroups(1, &pw->pw_gid))

       return _error->Errno("setgroups", "Failed to setgroups");
 
    if (setegid(pw->pw_gid) != 0)
       return _error->Errno("setgroups", "Failed to setgroups");
 
    if (setegid(pw->pw_gid) != 0)

-      return _error->Errno("setgid", "Failed to setgid");
+      return _error->Errno("setegid", "Failed to setegid");
+

    if (setgid(pw->pw_gid) != 0)
       return _error->Errno("setgid", "Failed to setgid");
    if (setgid(pw->pw_gid) != 0)
       return _error->Errno("setgid", "Failed to setgid");

-   
+

    if (setuid(pw->pw_uid) != 0)
       return _error->Errno("setuid", "Failed to setuid");
    if (setuid(pw->pw_uid) != 0)
       return _error->Errno("setuid", "Failed to setuid");

+

    // the seteuid() is probably uneeded (at least thats what the linux
    // man-page says about setuid(2)) but we cargo culted it anyway
    // the seteuid() is probably uneeded (at least thats what the linux
    // man-page says about setuid(2)) but we cargo culted it anyway

-   if (setuid(pw->pw_uid) != 0)
-      return _error->Errno("setuid", "Failed to setuid");
+   if (seteuid(pw->pw_uid) != 0)
+      return _error->Errno("seteuid", "Failed to seteuid");
+
+   // Verify that the user has only a single group, and the correct one
+   gid_t groups[1];
+   if (getgroups(1, groups) != 1)
+      return _error->Errno("getgroups", "Could not get new groups");
+   if (groups[0] != pw->pw_gid)
+      return _error->Error("Could not switch group");
+
+   // Verify that gid, egid, uid, and euid changed
+   if (getgid() != pw->pw_gid)
+      return _error->Error("Could not switch group");
+   if (getegid() != pw->pw_gid)
+      return _error->Error("Could not switch effective group");
+   if (getuid() != pw->pw_uid)
+      return _error->Error("Could not switch user");
+   if (geteuid() != pw->pw_uid)
+      return _error->Error("Could not switch effective user");
+
+#ifdef HAVE_GETRESUID
+   // verify that the saved set-user-id was changed as well
+   uid_t ruid = 0;
+   uid_t euid = 0;
+   uid_t suid = 0;
+   if (getresuid(&ruid, &euid, &suid))
+      return _error->Errno("getresuid", "Could not get saved set-user-ID");
+   if (suid != pw->pw_uid)
+      return _error->Error("Could not switch saved set-user-ID");
+#endif

 
 

-   // be defensive
-   if(setgid(0) != -1 || setegid(0) != -1)
-      return _error->Error("Could restore gid to root, privilege dropping does not work");
-   if(setuid(0) != -1 || seteuid(0) != -1)
-      return _error->Error("Could restore uid to root, privilege dropping does not work");
+#ifdef HAVE_GETRESGID
+   // verify that the saved set-group-id was changed as well
+   gid_t rgid = 0;
+   gid_t egid = 0;
+   gid_t sgid = 0;
+   if (getresgid(&rgid, &egid, &sgid))
+      return _error->Errno("getresuid", "Could not get saved set-group-ID");
+   if (sgid != pw->pw_gid)
+      return _error->Error("Could not switch saved set-group-ID");
+#endif
+
+   // Check that uid and gid changes do not work anymore
+   if (pw->pw_gid != old_gid && (setgid(old_gid) != -1 || setegid(old_gid) != -1))
+      return _error->Error("Could restore a gid to root, privilege dropping did not work");
+
+   if (pw->pw_uid != old_uid && (setuid(old_uid) != -1 || seteuid(old_uid) != -1))
+      return _error->Error("Could restore a uid to root, privilege dropping did not work");

 
    return true;
 }
 
    return true;
 }

+                                                                       /*}}}*/