From 76655d6dece88bd00e190956e8e4285b682edcbb Mon Sep 17 00:00:00 2001 From: aliguori Date: Fri, 6 Mar 2009 20:27:37 +0000 Subject: Support ACLs for controlling VNC access ("Daniel P. Berrange") This patch introduces a generic internal API for access control lists to be used by network servers in QEMU. It adds support for checking these ACL in the VNC server, in two places. The first ACL is for the SASL authentication mechanism, checking the SASL username. This ACL is called 'vnc.username'. The second is for the TLS authentication mechanism, when x509 client certificates are turned on, checking against the Distinguished Name of the client. This ACL is called 'vnc.x509dname' The internal API provides for an ACL with the following characteristics - A unique name, eg vnc.username, and vnc.x509dname. - A default policy, allow or deny - An ordered series of match rules, with allow or deny policy If none of the match rules apply, then the default policy is used. There is a monitor API to manipulate the ACLs, which I'll describe via examples (qemu) acl show vnc.username policy: allow (qemu) acl policy vnc.username denya acl: policy set to 'deny' (qemu) acl allow vnc.username fred acl: added rule at position 1 (qemu) acl allow vnc.username bob acl: added rule at position 2 (qemu) acl allow vnc.username joe 1 acl: added rule at position 1 (qemu) acl show vnc.username policy: deny 0: allow fred 1: allow joe 2: allow bob (qemu) acl show vnc.x509dname policy: allow (qemu) acl policy vnc.x509dname deny acl: policy set to 'deny' (qemu) acl allow vnc.x509dname C=GB,O=ACME,L=London,CN=* acl: added rule at position 1 (qemu) acl allow vnc.x509dname C=GB,O=ACME,L=Boston,CN=bob acl: added rule at position 2 (qemu) acl show vnc.x509dname policy: deny 0: allow C=GB,O=ACME,L=London,CN=* 1: allow C=GB,O=ACME,L=Boston,CN=bob By default the VNC server will not use any ACLs, allowing access to the server if the user successfully authenticates. To enable use of ACLs to restrict user access, the ',acl' flag should be given when starting QEMU. The initial ACL activated will be a 'deny all' policy and should be customized using monitor commands. eg enable SASL auth and ACLs qemu .... -vnc localhost:1,sasl,acl The next patch will provide a way to load a pre-defined ACL when starting up Makefile | 6 + b/acl.c | 185 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ b/acl.h | 74 ++++++++++++++++++++++ configure | 18 +++++ monitor.c | 95 ++++++++++++++++++++++++++++ qemu-doc.texi | 49 ++++++++++++++ vnc-auth-sasl.c | 16 +++- vnc-auth-sasl.h | 7 ++ vnc-tls.c | 19 +++++ vnc-tls.h | 3 vnc.c | 21 ++++++ vnc.h | 3 12 files changed, 491 insertions(+), 5 deletions(-) Signed-off-by: Daniel P. Berrange Signed-off-by: Anthony Liguori git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6726 c046a42c-6fe2-441c-8c8c-71466251a162 --- monitor.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) (limited to 'monitor.c') diff --git a/monitor.c b/monitor.c index 85da239..3d81fbc 100644 --- a/monitor.c +++ b/monitor.c @@ -41,6 +41,7 @@ #include "qemu-timer.h" #include "migration.h" #include "kvm.h" +#include "acl.h" //#define DEBUG //#define DEBUG_COMPLETION @@ -1532,6 +1533,86 @@ static void do_info_balloon(Monitor *mon) monitor_printf(mon, "balloon: actual=%d\n", (int)(actual >> 20)); } +static void do_acl(Monitor *mon, + const char *command, + const char *aclname, + const char *match, + int has_index, + int index) +{ + qemu_acl *acl; + + acl = qemu_acl_find(aclname); + if (!acl) { + monitor_printf(mon, "acl: unknown list '%s'\n", aclname); + return; + } + + if (strcmp(command, "show") == 0) { + int i = 0; + qemu_acl_entry *entry; + monitor_printf(mon, "policy: %s\n", + acl->defaultDeny ? "deny" : "allow"); + TAILQ_FOREACH(entry, &acl->entries, next) { + i++; + monitor_printf(mon, "%d: %s %s\n", i, + entry->deny ? "deny" : "allow", + entry->match); + } + } else if (strcmp(command, "reset") == 0) { + qemu_acl_reset(acl); + monitor_printf(mon, "acl: removed all rules\n"); + } else if (strcmp(command, "policy") == 0) { + if (!match) { + monitor_printf(mon, "acl: missing policy parameter\n"); + return; + } + + if (strcmp(match, "allow") == 0) { + acl->defaultDeny = 0; + monitor_printf(mon, "acl: policy set to 'allow'\n"); + } else if (strcmp(match, "deny") == 0) { + acl->defaultDeny = 1; + monitor_printf(mon, "acl: policy set to 'deny'\n"); + } else { + monitor_printf(mon, "acl: unknown policy '%s', expected 'deny' or 'allow'\n", match); + } + } else if ((strcmp(command, "allow") == 0) || + (strcmp(command, "deny") == 0)) { + int deny = strcmp(command, "deny") == 0 ? 1 : 0; + int ret; + + if (!match) { + monitor_printf(mon, "acl: missing match parameter\n"); + return; + } + + if (has_index) + ret = qemu_acl_insert(acl, deny, match, index); + else + ret = qemu_acl_append(acl, deny, match); + if (ret < 0) + monitor_printf(mon, "acl: unable to add acl entry\n"); + else + monitor_printf(mon, "acl: added rule at position %d\n", ret); + } else if (strcmp(command, "remove") == 0) { + int ret; + + if (!match) { + monitor_printf(mon, "acl: missing match parameter\n"); + return; + } + + ret = qemu_acl_remove(acl, match); + if (ret < 0) + monitor_printf(mon, "acl: no matching acl entry\n"); + else + monitor_printf(mon, "acl: removed rule at position %d\n", ret); + } else { + monitor_printf(mon, "acl: unknown command '%s'\n", command); + } +} + /* Please update qemu-doc.texi when adding or changing commands */ static const mon_cmd_t mon_cmds[] = { { "help|?", "s?", help_cmd, @@ -1636,6 +1717,12 @@ static const mon_cmd_t mon_cmds[] = { "target", "request VM to change it's memory allocation (in MB)" }, { "set_link", "ss", do_set_link, "name [up|down]", "change the link status of a network adapter" }, + { "acl", "sss?i?", do_acl, " [] []\n", + "acl show vnc.username\n" + "acl policy vnc.username deny\n" + "acl allow vnc.username fred\n" + "acl deny vnc.username bob\n" + "acl reset vnc.username\n" }, { NULL, NULL, }, }; @@ -2961,6 +3048,15 @@ static void monitor_event(void *opaque, int event) } } + +/* + * Local variables: + * c-indent-level: 4 + * c-basic-offset: 4 + * tab-width: 8 + * End: + */ + void monitor_init(CharDriverState *chr, int flags) { static int is_first_init = 1; -- cgit v1.1