Add helpers for getting env vars in a setuid environment

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)

diff --git a/bootstrap.conf b/bootstrap.conf
index 68c4a890c5159f916f323ebf04077510ecc3374b..8a4368b8ccef7beb05dfe74c8816d529af85f184 100644 (file)
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -93,6 +93,7 @@ recv
 regex
 random_r
 sched
+secure_getenv
 send
 setenv
 setsockopt

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 35f0f1bb83e9f07b590c9b5f78d786f0e9135916..e5203246a789886da25b298aaff6f7d0ababc065 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2042,6 +2042,8 @@ virFindFCHostCapableVport;
 virFormatIntDecimal;
 virGetDeviceID;
 virGetDeviceUnprivSGIO;
+virGetEnvAllowSUID;
+virGetEnvBlockSUID;
 virGetFCHostNameByWWN;
 virGetGroupID;
 virGetGroupList;
@@ -2060,6 +2062,7 @@ virIndexToDiskName;
 virIsCapableFCHost;
 virIsCapableVport;
 virIsDevMapperDevice;
+virIsSUID;
 virManageVport;
 virParseNumber;
 virParseOwnershipIds;

diff --git a/src/util/virutil.c b/src/util/virutil.c
index 34f59983a6306b20a6a6c93898dbf1a751465a8e..c1d15b2f4ce0d507b2d211287369e7d401e465c6 100644 (file)
--- a/src/util/virutil.c
+++ b/src/util/virutil.c
@@ -2116,3 +2116,42 @@ 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 4b06992346d853b02b49a200bb9f60e2832ddf66..8739e4edb1a0690041e883678272561cc7e3a294 100644 (file)
--- 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__ */