From ffe48a81783cc07e2f12e158e5b3985d1f313c9b Mon Sep 17 00:00:00 2001
Message-Id: <ffe48a81783cc07e2f12e158e5b3985d1f313c9b.1383321464.git.jdenemar@redhat.com>
From: "Daniel P. Berrange" <berrange@redhat.com>
Date: Wed, 30 Oct 2013 17:01:41 +0000
Subject: [PATCH] Add helpers for getting env vars in a setuid environment

For

  https://bugzilla.redhat.com/show_bug.cgi?id=1015247

Care must be taken accessing env variables when running
setuid. Introduce a virGetEnvAllowSUID for env vars which
are safe to use in a setuid environment, and another
virGetEnvBlockSUID for vars which are not safe. Also add
a virIsSUID helper method for any other non-env var code
to use.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
(cherry picked from commit ae53e5d10e434e07079d7e3ba11ec654ba6a256e)
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 bootstrap.conf           |  1 +
 src/libvirt_private.syms |  3 +++
 src/util/virutil.c       | 39 +++++++++++++++++++++++++++++++++++++++
 src/util/virutil.h       |  4 ++++
 4 files changed, 47 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index f96f126..374a332 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2046,6 +2046,8 @@ virFindFCHostCapableVport;
 virFormatIntDecimal;
 virGetDeviceID;
 virGetDeviceUnprivSGIO;
+virGetEnvAllowSUID;
+virGetEnvBlockSUID;
 virGetFCHostNameByWWN;
 virGetGroupID;
 virGetGroupList;
@@ -2064,6 +2066,7 @@ virIndexToDiskName;
 virIsCapableFCHost;
 virIsCapableVport;
 virIsDevMapperDevice;
+virIsSUID;
 virManageVport;
 virParseNumber;
 virParseOwnershipIds;
diff --git a/src/util/virutil.c b/src/util/virutil.c
index 3abcd53..a41117e 100644
--- a/src/util/virutil.c
+++ b/src/util/virutil.c
@@ -2096,3 +2096,42 @@ cleanup:
 
     return rc;
 }
+
+
+/**
+ * virGetEnvBlockSUID:
+ * @name: the environment variable name
+ *
+ * Obtain an environment variable which is unsafe to
+ * use when running setuid. If running setuid, a NULL
+ * value will be returned
+ */
+const char *virGetEnvBlockSUID(const char *name)
+{
+    return secure_getenv(name);
+}
+
+
+/**
+ * virGetEnvBlockSUID:
+ * @name: the environment variable name
+ *
+ * Obtain an environment variable which is safe to
+ * use when running setuid. The value will be returned
+ * even when running setuid
+ */
+const char *virGetEnvAllowSUID(const char *name)
+{
+    return getenv(name);
+}
+
+
+/**
+ * virIsSUID:
+ * Return a true value if running setuid. Does not
+ * check for elevated capabilities bits.
+ */
+bool virIsSUID(void)
+{
+    return getuid() != geteuid();
+}
diff --git a/src/util/virutil.h b/src/util/virutil.h
index 4b06992..8739e4e 100644
--- a/src/util/virutil.h
+++ b/src/util/virutil.h
@@ -172,4 +172,8 @@ int virCompareLimitUlong(unsigned long long a, unsigned long b);
 
 int virParseOwnershipIds(const char *label, uid_t *uidPtr, gid_t *gidPtr);
 
+const char *virGetEnvBlockSUID(const char *name);
+const char *virGetEnvAllowSUID(const char *name);
+bool virIsSUID(void);
+
 #endif /* __VIR_UTIL_H__ */
-- 
1.8.4.2