]> git.ipfire.org Git - thirdparty/libvirt.git/commitdiff
Include process start time when doing polkit checks
authorDaniel P. Berrange <berrange@redhat.com>
Thu, 25 Apr 2013 16:05:00 +0000 (17:05 +0100)
committerEric Blake <eblake@redhat.com>
Wed, 18 Sep 2013 14:33:49 +0000 (08:33 -0600)
Since PIDs can be reused, polkit prefers to be given
a (PID,start time) pair. If given a PID on its own,
it will attempt to lookup the start time in /proc/pid/stat,
though this is subject to races.

It is safer if the client app resolves the PID start
time itself, because as long as the app has the client
socket open, the client PID won't be reused.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 979e9c56a7aadf2dcfbddd1abfbad594b78b4468)
Signed-off-by: Eric Blake <eblake@redhat.com>
Conflicts:
src/libvirt_private.syms - not backported
src/locking/lock_daemon.c - not backported
src/rpc/virnetserverclient.c
src/rpc/virnetsocket.c
src/rpc/virnetsocket.h
src/util/viridentity.h - not backported
src/util/virprocess.c
src/util/virprocess.h
src/util/virstring.c
src/util/virstring.h

Most conflicts were contextual (this patch adds new functions,
but upstream intermediate patches not backported here also added
new features, and the resolution was picking out just the portions
needed by this commit).  virnetsocket.c also had slightly
different locking semantics.

daemon/remote.c
src/rpc/virnetserverclient.c
src/rpc/virnetserverclient.h
src/rpc/virnetsocket.c
src/rpc/virnetsocket.h
src/util/virprocess.c
src/util/virprocess.h
src/util/virstring.c
src/util/virstring.h

index 4b89df3f39457b972060f867a0ce57488b9a3187..dd608cdc552af1fb37ab43b55bd8c418e1389dcf 100644 (file)
@@ -2351,6 +2351,7 @@ remoteDispatchAuthList(virNetServerPtr server ATTRIBUTE_UNUSED,
     uid_t callerUid;
     gid_t callerGid;
     pid_t callerPid;
+    unsigned long long timestamp;
 
     /* If the client is root then we want to bypass the
      * policykit auth to avoid root being denied if
@@ -2358,7 +2359,7 @@ remoteDispatchAuthList(virNetServerPtr server ATTRIBUTE_UNUSED,
      */
     if (auth == VIR_NET_SERVER_SERVICE_AUTH_POLKIT) {
         if (virNetServerClientGetUNIXIdentity(client, &callerUid, &callerGid,
-                                              &callerPid) < 0) {
+                                              &callerPid, &timestamp) < 0) {
             /* Don't do anything on error - it'll be validated at next
              * phase of auth anyway */
             virResetLastError();
@@ -2786,6 +2787,7 @@ remoteDispatchAuthPolkit(virNetServerPtr server ATTRIBUTE_UNUSED,
     pid_t callerPid = -1;
     gid_t callerGid = -1;
     uid_t callerUid = -1;
+    unsigned long long timestamp;
     const char *action;
     int status = -1;
     char *ident = NULL;
@@ -2811,7 +2813,7 @@ remoteDispatchAuthPolkit(virNetServerPtr server ATTRIBUTE_UNUSED,
     }
 
     if (virNetServerClientGetUNIXIdentity(client, &callerUid, &callerGid,
-                                          &callerPid) < 0) {
+                                          &callerPid, &timestamp) < 0) {
         goto authfail;
     }
 
@@ -2819,7 +2821,11 @@ remoteDispatchAuthPolkit(virNetServerPtr server ATTRIBUTE_UNUSED,
              (long long) callerPid, callerUid);
 
     virCommandAddArg(cmd, "--process");
-    virCommandAddArgFormat(cmd, "%lld", (long long) callerPid);
+    if (timestamp != 0) {
+        virCommandAddArgFormat(cmd, "%lld,%llu", (long long) callerPid, timestamp);
+    } else {
+        virCommandAddArgFormat(cmd, "%lld", (long long) callerPid);
+    }
     virCommandAddArg(cmd, "--allow-user-interaction");
 
     if (virAsprintf(&ident, "pid:%lld,uid:%d",
index 1ac5677f34805260bc37b99b0a3f2a4736b1315c..c49e3c2cc8631e3bf66911e1ebe1b6f63128a18e 100644 (file)
@@ -466,16 +466,20 @@ int virNetServerClientGetFD(virNetServerClientPtr client)
 }
 
 int virNetServerClientGetUNIXIdentity(virNetServerClientPtr client,
-                                      uid_t *uid, gid_t *gid, pid_t *pid)
+                                      uid_t *uid, gid_t *gid, pid_t *pid,
+                                      unsigned long long *timestamp)
 {
     int ret = -1;
     virNetServerClientLock(client);
     if (client->sock)
-        ret = virNetSocketGetUNIXIdentity(client->sock, uid, gid, pid);
+        ret = virNetSocketGetUNIXIdentity(client->sock,
+                                          uid, gid, pid,
+                                          timestamp);
     virNetServerClientUnlock(client);
     return ret;
 }
 
+
 bool virNetServerClientIsSecure(virNetServerClientPtr client)
 {
     bool secure = false;
index 3ce1889367eee44df07fc52aaca408e23dd25b0c..2e97b42f0c3d199109f47b446b7e295d537007a8 100644 (file)
@@ -78,7 +78,8 @@ int virNetServerClientSetIdentity(virNetServerClientPtr client,
 const char *virNetServerClientGetIdentity(virNetServerClientPtr client);
 
 int virNetServerClientGetUNIXIdentity(virNetServerClientPtr client,
-                                      uid_t *uid, gid_t *gid, pid_t *pid);
+                                      uid_t *uid, gid_t *gid, pid_t *pid,
+                                      unsigned long long *timestamp);
 
 void *virNetServerClientGetPrivateData(virNetServerClientPtr client);
 
index 6ffa06e5b986c451e72e2f97c1630a09f844c49f..97d50c0f7f397e8fc9d7eb9f9f9112b797783629 100644 (file)
@@ -987,31 +987,40 @@ int virNetSocketGetPort(virNetSocketPtr sock)
 int virNetSocketGetUNIXIdentity(virNetSocketPtr sock,
                                 uid_t *uid,
                                 gid_t *gid,
-                                pid_t *pid)
+                                pid_t *pid,
+                                unsigned long long *timestamp)
 {
     struct ucred cr;
     socklen_t cr_len = sizeof(cr);
+    int ret = -1;
+
     virMutexLock(&sock->lock);
 
     if (getsockopt(sock->fd, SOL_SOCKET, SO_PEERCRED, &cr, &cr_len) < 0) {
         virReportSystemError(errno, "%s",
                              _("Failed to get client socket identity"));
-        virMutexUnlock(&sock->lock);
-        return -1;
+        goto cleanup;
     }
 
+    if (virProcessGetStartTime(cr.pid, timestamp) < 0)
+        goto cleanup;
+
     *pid = cr.pid;
     *uid = cr.uid;
     *gid = cr.gid;
 
+    ret = 0;
+
+cleanup:
     virMutexUnlock(&sock->lock);
-    return 0;
+    return ret;
 }
 #else
 int virNetSocketGetUNIXIdentity(virNetSocketPtr sock ATTRIBUTE_UNUSED,
                                 uid_t *uid ATTRIBUTE_UNUSED,
                                 gid_t *gid ATTRIBUTE_UNUSED,
-                                pid_t *pid ATTRIBUTE_UNUSED)
+                                pid_t *pid ATTRIBUTE_UNUSED,
+                                unsigned long long *timestamp ATTRIBUTE_UNUSED)
 {
     /* XXX Many more OS support UNIX socket credentials we could port to. See dbus ....*/
     virReportSystemError(ENOSYS, "%s",
index 261d923e7741c0fddca8240d6a0041252a514415..3d88cc3a3f01290002ad3c19429a12b342790565 100644 (file)
@@ -105,7 +105,8 @@ int virNetSocketGetPort(virNetSocketPtr sock);
 int virNetSocketGetUNIXIdentity(virNetSocketPtr sock,
                                 uid_t *uid,
                                 gid_t *gid,
-                                pid_t *pid);
+                                pid_t *pid,
+                                unsigned long long *timestamp);
 
 int virNetSocketSetBlocking(virNetSocketPtr sock,
                             bool blocking);
index 958f5f7960e86d52baf39a753902718fd2659416..08a6f19e6facdc8242577a6e0e1e1418422ef24a 100644 (file)
 #include <errno.h>
 #include <sys/wait.h>
 
+#ifdef __FreeBSD__
+# include <sys/param.h>
+# include <sys/sysctl.h>
+# include <sys/user.h>
+#endif
+
+#include "viratomic.h"
 #include "virprocess.h"
 #include "virterror_internal.h"
 #include "memory.h"
 #include "logging.h"
 #include "util.h"
+#include "virstring.h"
 
 #define VIR_FROM_THIS VIR_FROM_NONE
 
@@ -235,3 +243,113 @@ int virProcessKill(pid_t pid, int sig)
     return kill(pid, sig);
 #endif
 }
+
+
+#ifdef __linux__
+/*
+ * Port of code from polkitunixprocess.c under terms
+ * of the LGPLv2+
+ */
+int virProcessGetStartTime(pid_t pid,
+                           unsigned long long *timestamp)
+{
+    char *filename = NULL;
+    char *buf = NULL;
+    char *tmp;
+    int ret = -1;
+    int len;
+    char **tokens = NULL;
+
+    if (virAsprintf(&filename, "/proc/%llu/stat",
+                    (unsigned long long)pid) < 0) {
+        virReportOOMError();
+        return -1;
+    }
+
+    if ((len = virFileReadAll(filename, 1024, &buf)) < 0)
+        goto cleanup;
+
+    /* start time is the token at index 19 after the '(process name)' entry - since only this
+     * field can contain the ')' character, search backwards for this to avoid malicious
+     * processes trying to fool us
+     */
+
+    if (!(tmp = strrchr(buf, ')'))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Cannot find start time in %s"),
+                       filename);
+        goto cleanup;
+    }
+    tmp += 2; /* skip ') ' */
+    if ((tmp - buf) >= len) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Cannot find start time in %s"),
+                       filename);
+        goto cleanup;
+    }
+
+    tokens = virStringSplit(tmp, " ", 0);
+
+    if (virStringListLength(tokens) < 20) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Cannot find start time in %s"),
+                       filename);
+        goto cleanup;
+    }
+
+    if (virStrToLong_ull(tokens[19],
+                         NULL,
+                         10,
+                         timestamp) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Cannot parse start time %s in %s"),
+                       tokens[19], filename);
+        goto cleanup;
+    }
+
+    ret = 0;
+
+cleanup:
+    virStringFreeList(tokens);
+    VIR_FREE(filename);
+    VIR_FREE(buf);
+    return ret;
+}
+#elif defined(__FreeBSD__)
+int virProcessGetStartTime(pid_t pid,
+                           unsigned long long *timestamp)
+{
+    struct kinfo_proc p;
+    int mib[4];
+    size_t len = 4;
+
+    sysctlnametomib("kern.proc.pid", mib, &len);
+
+    len = sizeof(struct kinfo_proc);
+    mib[3] = pid;
+
+    if (sysctl(mib, 4, &p, &len, NULL, 0) < 0) {
+        virReportSystemError(errno, "%s",
+                             _("Unable to query process ID start time"));
+        return -1;
+    }
+
+    *timestamp = (unsigned long long)p.ki_start.tv_sec;
+
+    return 0;
+
+}
+#else
+int virProcessGetStartTime(pid_t pid,
+                           unsigned long long *timestamp)
+{
+    static int warned = 0;
+    if (virAtomicIntInc(&warned) == 1) {
+        VIR_WARN("Process start time of pid %llu not available on this platform",
+                 (unsigned long long)pid);
+        warned = true;
+    }
+    *timestamp = 0;
+    return 0;
+}
+#endif
index 048a73c0717db81fee43eee1e79cedfd27098bb6..30ca21f37e7d573e097ffb3d5bc209607f6deac9 100644 (file)
@@ -39,4 +39,7 @@ virProcessWait(pid_t pid, int *exitstatus)
 int virProcessKill(pid_t pid, int sig);
 
 
+int virProcessGetStartTime(pid_t pid,
+                           unsigned long long *timestamp);
+
 #endif /* __VIR_PROCESS_H__ */
index 1917e9a6bd115df7265df206760480768e230ed5..92289eb93c3fb20f0a25dce2dc10e672fe9e4230 100644 (file)
@@ -166,3 +166,14 @@ void virStringFreeList(char **strings)
     }
     VIR_FREE(strings);
 }
+
+
+size_t virStringListLength(char **strings)
+{
+    size_t i = 0;
+
+    while (strings && strings[i])
+        i++;
+
+    return i;
+}
index a569fe080a6262e5af1b49452646a8b2b2a72f3b..d68ed2f68972e156c38120877cdb3b3e2b71c1e1 100644 (file)
@@ -35,4 +35,6 @@ char *virStringJoin(const char **strings,
 
 void virStringFreeList(char **strings);
 
+size_t virStringListLength(char **strings);
+
 #endif /* __VIR_STRING_H__ */