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-rw-r--r--src/Makefile.am2
-rw-r--r--src/libexpr/parser.cc2
-rw-r--r--src/libmain/shared.cc61
-rw-r--r--src/libstore/store.cc11
-rw-r--r--src/libutil/util.hh10
-rw-r--r--src/nix-env/main.cc3
6 files changed, 74 insertions, 15 deletions
diff --git a/src/Makefile.am b/src/Makefile.am
index b7eb905f9..563738217 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -4,7 +4,7 @@ SUBDIRS = bin2c boost libutil libstore libmain nix-store nix-hash \
SETUID_PROGS = nix-store nix-instantiate nix-env
install-exec-hook:
if SETUID_HACK
-if HAVE_SETREUID
+if HAVE_SETRESUID
cd $(DESTDIR)$(bindir) && chown @NIX_USER@ $(SETUID_PROGS) \
&& chgrp @NIX_GROUP@ $(SETUID_PROGS) && chmod ug+s $(SETUID_PROGS)
else
diff --git a/src/libexpr/parser.cc b/src/libexpr/parser.cc
index 90e008473..763faacf7 100644
--- a/src/libexpr/parser.cc
+++ b/src/libexpr/parser.cc
@@ -106,6 +106,8 @@ static Expr parse(EvalState & state,
Expr parseExprFromFile(EvalState & state, Path path)
{
+ SwitchToOriginalUser sw;
+
assert(path[0] == '/');
#if 0
diff --git a/src/libmain/shared.cc b/src/libmain/shared.cc
index d0ea3aab8..5affce77e 100644
--- a/src/libmain/shared.cc
+++ b/src/libmain/shared.cc
@@ -169,9 +169,14 @@ static void initAndRun(int argc, char * * argv)
}
-#if HAVE_SETREUID
-#define _setuid(uid) setreuid(uid, uid)
-#define _setgid(gid) setregid(gid, gid)
+static bool haveSwitched;
+static uid_t savedUid, nixUid;
+static gid_t savedGid, nixGid;
+
+
+#if HAVE_SETRESUID
+#define _setuid(uid) setresuid(uid, uid, savedUid)
+#define _setgid(gid) setresgid(gid, gid, savedGid)
#else
/* Only works properly when run by root. */
#define _setuid(uid) setuid(uid)
@@ -179,6 +184,37 @@ static void initAndRun(int argc, char * * argv)
#endif
+SwitchToOriginalUser::SwitchToOriginalUser()
+{
+#if SETUID_HACK && HAVE_SETRESUID
+ /* Temporarily switch the effective uid/gid back to the saved
+ uid/gid (which is the uid/gid of the user that executed the Nix
+ program; it's *not* the real uid/gid, since we changed that to
+ the Nix user in switchToNixUser()). */
+ if (haveSwitched) {
+ if (setuid(savedUid) == -1)
+ throw SysError(format("temporarily restoring uid to `%1%'") % savedUid);
+ if (setgid(savedGid) == -1)
+ throw SysError(format("temporarily restoring gid to `%1%'") % savedGid);
+ }
+#endif
+}
+
+
+SwitchToOriginalUser::~SwitchToOriginalUser()
+{
+#if SETUID_HACK && HAVE_SETRESUID
+ /* Switch the effective uid/gid back to the Nix user. */
+ if (haveSwitched) {
+ if (setuid(nixUid) == -1)
+ throw SysError(format("restoring uid to `%1%'") % nixUid);
+ if (setgid(nixGid) == -1)
+ throw SysError(format("restoring gid to `%1%'") % nixGid);
+ }
+#endif
+}
+
+
void switchToNixUser()
{
#if SETUID_HACK
@@ -208,7 +244,7 @@ void switchToNixUser()
/* !!! Apparently it is unspecified whether getgroups() includes
the effective gid. In that case the following test is always
true *if* the program is installed setgid (which we do when we
- have setreuid()). On Linux this doesn't appear to be the
+ have setresuid()). On Linux this doesn't appear to be the
case, but we should switch to the real gid before doing this
test, and then switch back to the saved gid. */
@@ -227,13 +263,14 @@ void switchToNixUser()
return;
}
+ savedUid = getuid();
+ savedGid = getgid();
+
/* Set the real, effective and saved gids to gr->gr_gid. Also
make very sure that this succeeded. We switch the gid first
because we cannot do it after we have dropped root uid. */
- if (_setgid(gr->gr_gid) != 0 ||
- getgid() != gr->gr_gid ||
- getegid() != gr->gr_gid)
- {
+ nixGid = gr->gr_gid;
+ if (_setgid(nixGid) != 0 || getgid() != nixGid || getegid() != nixGid) {
cerr << format("unable to set gid to `%1%'\n") % NIX_GROUP;
exit(1);
}
@@ -248,14 +285,14 @@ void switchToNixUser()
/* This will drop all root privileges, setting the real, effective
and saved uids to pw->pw_uid. Also make very sure that this
succeeded.*/
- if (_setuid(pw->pw_uid) != 0 ||
- getuid() != pw->pw_uid ||
- geteuid() != pw->pw_uid)
- {
+ nixUid = pw->pw_uid;
+ if (_setuid(nixUid) != 0 || getuid() != nixUid || geteuid() != nixUid) {
cerr << format("unable to set uid to `%1%'\n") % NIX_USER;
exit(1);
}
+ haveSwitched = true;
+
#endif
}
diff --git a/src/libstore/store.cc b/src/libstore/store.cc
index 110ec2b48..5b471a1d9 100644
--- a/src/libstore/store.cc
+++ b/src/libstore/store.cc
@@ -157,7 +157,10 @@ void copyPath(const Path & src, const Path & dst)
CopySink sink;
sink.fd = pipe.writeSide;
- dumpPath(src, sink);
+ {
+ SwitchToOriginalUser sw;
+ dumpPath(src, sink);
+ }
/* Wait for the child to finish. */
int status = pid.wait(true);
@@ -421,7 +424,11 @@ Path addToStore(const Path & _srcPath)
Path srcPath(absPath(_srcPath));
debug(format("adding `%1%' to the store") % srcPath);
- Hash h = hashPath(srcPath);
+ Hash h;
+ {
+ SwitchToOriginalUser sw;
+ h = hashPath(srcPath);
+ }
string baseName = baseNameOf(srcPath);
Path dstPath = canonPath(nixStore + "/" + (string) h + "-" + baseName);
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 13f28dc22..ae5b4882e 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -246,4 +246,14 @@ string statusToString(int status);
bool statusOk(int status);
+/* !!! HACK HACK HACK - this should be in shared.hh, but it's to
+ facilitate a quick hack - will remove this eventually (famous last
+ words). */
+struct SwitchToOriginalUser
+{
+ SwitchToOriginalUser();
+ ~SwitchToOriginalUser();
+};
+
+
#endif /* !__UTIL_H */
diff --git a/src/nix-env/main.cc b/src/nix-env/main.cc
index 3700f4489..14aa13b86 100644
--- a/src/nix-env/main.cc
+++ b/src/nix-env/main.cc
@@ -600,6 +600,7 @@ static void opSwitchProfile(Globals & globals,
Path profile = opArgs.front();
Path profileLink = getHomeDir() + "/.nix-profile";
+ SwitchToOriginalUser sw;
switchLink(profileLink, profile);
}
@@ -698,6 +699,7 @@ static void opDefaultExpr(Globals & globals,
Path defNixExpr = absPath(opArgs.front());
Path defNixExprLink = getDefNixExprPath();
+ SwitchToOriginalUser sw;
switchLink(defNixExprLink, defNixExpr);
}
@@ -772,6 +774,7 @@ void run(Strings args)
if (!op) throw UsageError("no operation specified");
if (globals.profile == "") {
+ SwitchToOriginalUser sw;
Path profileLink = getHomeDir() + "/.nix-profile";
globals.profile = pathExists(profileLink)
? absPath(readLink(profileLink), dirOf(profileLink))
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-23 22:04:14 +0000