From 4407b19b83d298535515ee57295a50394d3be14d Mon Sep 17 00:00:00 2001 From: "Daniel P. Berrange" Date: Thu, 25 Apr 2013 17:05:00 +0100 Subject: [PATCH] Include process start time when doing polkit checks 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 (cherry picked from commit 979e9c56a7aadf2dcfbddd1abfbad594b78b4468) Signed-off-by: Eric Blake Conflicts: src/rpc/virnetsocket.h - context src/util/virprocess.c - needed #include "virstring.h" src/util/virstring.c - context src/util/virstring.h - context --- daemon/remote.c | 12 +++- src/libvirt_private.syms | 1 + src/locking/lock_daemon.c | 4 +- src/rpc/virnetserverclient.c | 28 +++++++-- src/rpc/virnetserverclient.h | 3 +- src/rpc/virnetsocket.c | 23 +++++-- src/rpc/virnetsocket.h | 3 +- src/util/viridentity.h | 1 + src/util/virprocess.c | 117 +++++++++++++++++++++++++++++++++++ src/util/virprocess.h | 3 + src/util/virstring.c | 11 ++++ src/util/virstring.h | 2 + 12 files changed, 191 insertions(+), 17 deletions(-) diff --git a/daemon/remote.c b/daemon/remote.c index dd72f9fff6..cf43f04640 100644 --- a/daemon/remote.c +++ b/daemon/remote.c @@ -2370,6 +2370,7 @@ 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 @@ -2377,7 +2378,7 @@ remoteDispatchAuthList(virNetServerPtr server ATTRIBUTE_UNUSED, */ if (auth == VIR_NET_SERVER_SERVICE_AUTH_POLKIT) { if (virNetServerClientGetUNIXIdentity(client, &callerUid, &callerGid, - &callerPid) < 0) { + &callerPid, ×tamp) < 0) { /* Don't do anything on error - it'll be validated at next * phase of auth anyway */ virResetLastError(); @@ -2803,6 +2804,7 @@ 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; @@ -2828,7 +2830,7 @@ remoteDispatchAuthPolkit(virNetServerPtr server ATTRIBUTE_UNUSED, } if (virNetServerClientGetUNIXIdentity(client, &callerUid, &callerGid, - &callerPid) < 0) { + &callerPid, ×tamp) < 0) { goto authfail; } @@ -2836,7 +2838,11 @@ 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", diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index bf3b426c78..67db6a178c 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1750,6 +1750,7 @@ virStorageFileResize; virStringArrayHasString; virStringFreeList; virStringJoin; +virStringListLength; virStringSplit; diff --git a/src/locking/lock_daemon.c b/src/locking/lock_daemon.c index 97e5d749c2..bf0ee8124e 100644 --- a/src/locking/lock_daemon.c +++ b/src/locking/lock_daemon.c @@ -782,6 +782,7 @@ virLockDaemonClientNew(virNetServerClientPtr client, virLockDaemonClientPtr priv; uid_t clientuid; gid_t clientgid; + unsigned long long timestamp; bool privileged = opaque != NULL; if (VIR_ALLOC(priv) < 0) { @@ -798,7 +799,8 @@ virLockDaemonClientNew(virNetServerClientPtr client, if (virNetServerClientGetUNIXIdentity(client, &clientuid, &clientgid, - &priv->clientPid) < 0) + &priv->clientPid, + ×tamp) < 0) goto error; VIR_DEBUG("New client pid %llu uid %llu", diff --git a/src/rpc/virnetserverclient.c b/src/rpc/virnetserverclient.c index 58fb0b4918..b63ae300b6 100644 --- a/src/rpc/virnetserverclient.c +++ b/src/rpc/virnetserverclient.c @@ -634,12 +634,15 @@ bool virNetServerClientIsLocal(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; virObjectLock(client); if (client->sock) - ret = virNetSocketGetUNIXIdentity(client->sock, uid, gid, pid); + ret = virNetSocketGetUNIXIdentity(client->sock, + uid, gid, pid, + timestamp); virObjectUnlock(client); return ret; } @@ -649,6 +652,7 @@ static virIdentityPtr virNetServerClientCreateIdentity(virNetServerClientPtr client) { char *processid = NULL; + char *processtime = NULL; char *username = NULL; char *groupname = NULL; #if WITH_SASL @@ -662,15 +666,23 @@ virNetServerClientCreateIdentity(virNetServerClientPtr client) gid_t gid; uid_t uid; pid_t pid; - if (virNetSocketGetUNIXIdentity(client->sock, &uid, &gid, &pid) < 0) + unsigned long long timestamp; + if (virNetSocketGetUNIXIdentity(client->sock, + &uid, &gid, &pid, + ×tamp) < 0) goto cleanup; if (!(username = virGetUserName(uid))) goto cleanup; if (!(groupname = virGetGroupName(gid))) goto cleanup; - if (virAsprintf(&processid, "%lld", - (long long)pid) < 0) { + if (virAsprintf(&processid, "%llu", + (unsigned long long)pid) < 0) { + virReportOOMError(); + goto cleanup; + } + if (virAsprintf(&processtime, "%llu", + timestamp) < 0) { virReportOOMError(); goto cleanup; } @@ -720,6 +732,11 @@ virNetServerClientCreateIdentity(virNetServerClientPtr client) VIR_IDENTITY_ATTR_UNIX_PROCESS_ID, processid) < 0) goto error; + if (processtime && + virIdentitySetAttr(ret, + VIR_IDENTITY_ATTR_UNIX_PROCESS_TIME, + processtime) < 0) + goto error; #if HAVE_SASL if (saslname && virIdentitySetAttr(ret, @@ -742,6 +759,7 @@ cleanup: VIR_FREE(username); VIR_FREE(groupname); VIR_FREE(processid); + VIR_FREE(processtime); VIR_FREE(seccontext); #if HAVE_SASL VIR_FREE(saslname); diff --git a/src/rpc/virnetserverclient.h b/src/rpc/virnetserverclient.h index b3b8df0bf9..2a64d45ef8 100644 --- a/src/rpc/virnetserverclient.h +++ b/src/rpc/virnetserverclient.h @@ -99,7 +99,8 @@ bool virNetServerClientIsSecure(virNetServerClientPtr client); bool virNetServerClientIsLocal(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 virNetServerClientGetSecurityContext(virNetServerClientPtr client, char **context); diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c index 14c4a4f907..d754b3e067 100644 --- a/src/rpc/virnetsocket.c +++ b/src/rpc/virnetsocket.c @@ -1103,31 +1103,41 @@ 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; + virObjectLock(sock); if (getsockopt(sock->fd, SOL_SOCKET, SO_PEERCRED, &cr, &cr_len) < 0) { virReportSystemError(errno, "%s", _("Failed to get client socket identity")); - virObjectUnlock(sock); - return -1; + goto cleanup; } + if (virProcessGetStartTime(cr.pid, timestamp) < 0) + goto cleanup; + *pid = cr.pid; *uid = cr.uid; *gid = cr.gid; + ret = 0; + +cleanup: virObjectUnlock(sock); - return 0; + return ret; } #elif defined(LOCAL_PEERCRED) + int virNetSocketGetUNIXIdentity(virNetSocketPtr sock, uid_t *uid, gid_t *gid, - pid_t *pid) + pid_t *pid, + unsigned long long *timestamp ATTRIBUTE_UNUSED) { struct xucred cr; socklen_t cr_len = sizeof(cr); @@ -1151,7 +1161,8 @@ int virNetSocketGetUNIXIdentity(virNetSocketPtr sock, 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", diff --git a/src/rpc/virnetsocket.h b/src/rpc/virnetsocket.h index 7392c722bf..a0536f262d 100644 --- a/src/rpc/virnetsocket.h +++ b/src/rpc/virnetsocket.h @@ -113,7 +113,8 @@ 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 virNetSocketGetSecurityContext(virNetSocketPtr sock, char **context); diff --git a/src/util/viridentity.h b/src/util/viridentity.h index 39ab20ef9e..78680b51d3 100644 --- a/src/util/viridentity.h +++ b/src/util/viridentity.h @@ -31,6 +31,7 @@ typedef enum { VIR_IDENTITY_ATTR_UNIX_USER_NAME, VIR_IDENTITY_ATTR_UNIX_GROUP_NAME, VIR_IDENTITY_ATTR_UNIX_PROCESS_ID, + VIR_IDENTITY_ATTR_UNIX_PROCESS_TIME, VIR_IDENTITY_ATTR_SASL_USER_NAME, VIR_IDENTITY_ATTR_X509_DISTINGUISHED_NAME, VIR_IDENTITY_ATTR_SECURITY_CONTEXT, diff --git a/src/util/virprocess.c b/src/util/virprocess.c index 86d872e563..99db003352 100644 --- a/src/util/virprocess.c +++ b/src/util/virprocess.c @@ -33,12 +33,20 @@ #endif #include +#ifdef __FreeBSD__ +# include +# include +# include +#endif + +#include "viratomic.h" #include "virprocess.h" #include "virerror.h" #include "viralloc.h" #include "virfile.h" #include "virlog.h" #include "virutil.h" +#include "virstring.h" #define VIR_FROM_THIS VIR_FROM_NONE @@ -755,3 +763,112 @@ virProcessSetMaxFiles(pid_t pid ATTRIBUTE_UNUSED, unsigned int files) return -1; } #endif /* ! (HAVE_SETRLIMIT && defined(RLIMIT_NOFILE)) */ + +#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 diff --git a/src/util/virprocess.h b/src/util/virprocess.h index 5dea334902..9f77bc5491 100644 --- a/src/util/virprocess.h +++ b/src/util/virprocess.h @@ -47,6 +47,9 @@ int virProcessGetAffinity(pid_t pid, virBitmapPtr *map, int maxcpu); +int virProcessGetStartTime(pid_t pid, + unsigned long long *timestamp); + int virProcessGetNamespaces(pid_t pid, size_t *nfdlist, int **fdlist); diff --git a/src/util/virstring.c b/src/util/virstring.c index 122ebb8f0f..67c1dbbfef 100644 --- a/src/util/virstring.c +++ b/src/util/virstring.c @@ -180,3 +180,14 @@ virStringArrayHasString(char **strings, const char *needle) return false; } + + +size_t virStringListLength(char **strings) +{ + size_t i = 0; + + while (strings && strings[i]) + i++; + + return i; +} diff --git a/src/util/virstring.h b/src/util/virstring.h index 2ceadc6b84..8d1995a48b 100644 --- a/src/util/virstring.h +++ b/src/util/virstring.h @@ -37,4 +37,6 @@ void virStringFreeList(char **strings); bool virStringArrayHasString(char **strings, const char *needle); +size_t virStringListLength(char **strings); + #endif /* __VIR_STRING_H__ */ -- 2.47.2