daemon: Set ownership of kept build directories to the calling user.

Fixes <http://bugs.gnu.org/15890>.

* nix/libstore/globals.hh (Settings) Add clientUid and clientGid.
* nix/nix-daemon/nix-daemon.cc (daemonLoop] Store UID and GID of the
  caller in settings.
* nix/libstore/build.cc (_chown): New function.
  (DerivationGoal::deleteTmpDir): Use it, change ownership of build
  directory if it is kept and the new owner is not root.
This commit is contained in:
Hartmut Goebel 2016-11-21 19:49:12 +01:00
parent 43e8824d3c
commit 2608e40988
No known key found for this signature in database
GPG key ID: 634A8DFFD3F631DF
3 changed files with 39 additions and 0 deletions

View file

@ -2631,6 +2631,21 @@ void DerivationGoal::closeLogFile()
}
static void _chown(const Path & path, uid_t uid, gid_t gid)
{
checkInterrupt();
if (lchown(path.c_str(), uid, gid) == -1) {
throw SysError(format("change owner and group of `%1%'") % path);
}
struct stat st = lstat(path);
if (S_ISDIR(st.st_mode)) {
for (auto & i : readDirectory(path))
_chown(path + "/" + i.name, uid, gid);
}
}
void DerivationGoal::deleteTmpDir(bool force)
{
if (tmpDir != "") {
@ -2639,6 +2654,12 @@ void DerivationGoal::deleteTmpDir(bool force)
format("note: keeping build directory `%2%'")
% drvPath % tmpDir);
chmod(tmpDir.c_str(), 0755);
// Change the ownership if clientUid is set. Never change the
// ownership or the group to "root" for security reasons.
if (settings.clientUid != (uid_t) -1 && settings.clientUid != 0) {
_chown(tmpDir, settings.clientUid,
settings.clientGid != 0 ? settings.clientGid : -1);
}
}
else
deletePath(tmpDir);

View file

@ -70,6 +70,12 @@ struct Settings {
subgoal of the same goal) fails. */
bool keepGoing;
/* User and groud id of the client issuing the build request. Used to set
the owner and group of the kept temporary directories of failed
builds. */
uid_t clientUid;
gid_t clientGid;
/* Whether, if we cannot realise the known closure corresponding
to a derivation, we should try to normalise the derivation
instead. */

View file

@ -960,6 +960,18 @@ static void daemonLoop()
strncpy(argvSaved[1], processName.c_str(), strlen(argvSaved[1]));
}
#if defined(SO_PEERCRED)
/* Store the client's user and group for this connection. This
has to be done in the forked process since it is per
connection. */
settings.clientUid = cred.uid;
settings.clientGid = cred.gid;
#else
/* Setting these to -1 means: do not change */
settings.clientUid = (uid_t) -1;
settings.clientGid = (gid_t) -1;
#endif
/* Handle the connection. */
from.fd = remote;
to.fd = remote;