From e0d1caa7b0d5f02e4f34aa09c695d04251310c6c Mon Sep 17 00:00:00 2001 From: Venkat Yekkirala Date: Mon, 24 Jul 2006 23:29:07 -0700 Subject: [MLSXFRM]: Flow based matching of xfrm policy and state This implements a seemless mechanism for xfrm policy selection and state matching based on the flow sid. This also includes the necessary SELinux enforcement pieces. Signed-off-by: Venkat Yekkirala Signed-off-by: David S. Miller --- security/selinux/xfrm.c | 199 ++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 166 insertions(+), 33 deletions(-) (limited to 'security/selinux/xfrm.c') diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c index 6c985ced8102..a502b0540e3d 100644 --- a/security/selinux/xfrm.c +++ b/security/selinux/xfrm.c @@ -6,7 +6,12 @@ * Authors: Serge Hallyn * Trent Jaeger * + * Updated: Venkat Yekkirala + * + * Granular IPSec Associations for use in MLS environments. + * * Copyright (C) 2005 International Business Machines Corporation + * Copyright (C) 2006 Trusted Computer Solutions, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2, @@ -67,10 +72,10 @@ static inline int selinux_authorizable_xfrm(struct xfrm_state *x) } /* - * LSM hook implementation that authorizes that a socket can be used - * with the corresponding xfrm_sec_ctx and direction. + * LSM hook implementation that authorizes that a flow can use + * a xfrm policy rule. */ -int selinux_xfrm_policy_lookup(struct xfrm_policy *xp, u32 sk_sid, u8 dir) +int selinux_xfrm_policy_lookup(struct xfrm_policy *xp, u32 fl_secid, u8 dir) { int rc = 0; u32 sel_sid = SECINITSID_UNLABELED; @@ -84,27 +89,129 @@ int selinux_xfrm_policy_lookup(struct xfrm_policy *xp, u32 sk_sid, u8 dir) sel_sid = ctx->ctx_sid; } - rc = avc_has_perm(sk_sid, sel_sid, SECCLASS_ASSOCIATION, - ((dir == FLOW_DIR_IN) ? ASSOCIATION__RECVFROM : - ((dir == FLOW_DIR_OUT) ? ASSOCIATION__SENDTO : - (ASSOCIATION__SENDTO | ASSOCIATION__RECVFROM))), + rc = avc_has_perm(fl_secid, sel_sid, SECCLASS_ASSOCIATION, + ASSOCIATION__POLMATCH, NULL); return rc; } +/* + * LSM hook implementation that authorizes that a state matches + * the given policy, flow combo. + */ + +int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x, struct xfrm_policy *xp, + struct flowi *fl) +{ + u32 state_sid; + u32 pol_sid; + int err; + + if (x->security) + state_sid = x->security->ctx_sid; + else + state_sid = SECINITSID_UNLABELED; + + if (xp->security) + pol_sid = xp->security->ctx_sid; + else + pol_sid = SECINITSID_UNLABELED; + + err = avc_has_perm(state_sid, pol_sid, SECCLASS_ASSOCIATION, + ASSOCIATION__POLMATCH, + NULL); + + if (err) + return 0; + + return selinux_xfrm_flow_state_match(fl, x); +} + +/* + * LSM hook implementation that authorizes that a particular outgoing flow + * can use a given security association. + */ + +int selinux_xfrm_flow_state_match(struct flowi *fl, struct xfrm_state *xfrm) +{ + int rc = 0; + u32 sel_sid = SECINITSID_UNLABELED; + struct xfrm_sec_ctx *ctx; + + /* Context sid is either set to label or ANY_ASSOC */ + if ((ctx = xfrm->security)) { + if (!selinux_authorizable_ctx(ctx)) + return 0; + + sel_sid = ctx->ctx_sid; + } + + rc = avc_has_perm(fl->secid, sel_sid, SECCLASS_ASSOCIATION, + ASSOCIATION__SENDTO, + NULL)? 0:1; + + return rc; +} + +/* + * LSM hook implementation that determines the sid for the session. + */ + +int selinux_xfrm_decode_session(struct sk_buff *skb, struct flowi *fl) +{ + struct sec_path *sp; + + fl->secid = SECSID_NULL; + + if (skb == NULL) + return 0; + + sp = skb->sp; + if (sp) { + int i, sid_set = 0; + + for (i = sp->len-1; i >= 0; i--) { + struct xfrm_state *x = sp->xvec[i]; + if (selinux_authorizable_xfrm(x)) { + struct xfrm_sec_ctx *ctx = x->security; + + if (!sid_set) { + fl->secid = ctx->ctx_sid; + sid_set = 1; + } + else if (fl->secid != ctx->ctx_sid) + return -EINVAL; + } + } + } + + return 0; +} + /* * Security blob allocation for xfrm_policy and xfrm_state * CTX does not have a meaningful value on input */ -static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp, struct xfrm_user_sec_ctx *uctx) +static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp, + struct xfrm_user_sec_ctx *uctx, struct xfrm_sec_ctx *pol, u32 sid) { int rc = 0; struct task_security_struct *tsec = current->security; - struct xfrm_sec_ctx *ctx; + struct xfrm_sec_ctx *ctx = NULL; + char *ctx_str = NULL; + u32 str_len; + u32 ctx_sid; + + BUG_ON(uctx && pol); + + if (pol) + goto from_policy; BUG_ON(!uctx); - BUG_ON(uctx->ctx_doi != XFRM_SC_ALG_SELINUX); + + if (uctx->ctx_doi != XFRM_SC_ALG_SELINUX) + return -EINVAL; if (uctx->ctx_len >= PAGE_SIZE) return -ENOMEM; @@ -141,9 +248,41 @@ static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp, struct xfrm_us return rc; +from_policy: + BUG_ON(!pol); + rc = security_sid_mls_copy(pol->ctx_sid, sid, &ctx_sid); + if (rc) + goto out; + + rc = security_sid_to_context(ctx_sid, &ctx_str, &str_len); + if (rc) + goto out; + + *ctxp = ctx = kmalloc(sizeof(*ctx) + + str_len, + GFP_ATOMIC); + + if (!ctx) { + rc = -ENOMEM; + goto out; + } + + + ctx->ctx_doi = XFRM_SC_DOI_LSM; + ctx->ctx_alg = XFRM_SC_ALG_SELINUX; + ctx->ctx_sid = ctx_sid; + ctx->ctx_len = str_len; + memcpy(ctx->ctx_str, + ctx_str, + str_len); + + goto out2; + out: *ctxp = NULL; kfree(ctx); +out2: + kfree(ctx_str); return rc; } @@ -157,7 +296,7 @@ int selinux_xfrm_policy_alloc(struct xfrm_policy *xp, struct xfrm_user_sec_ctx * BUG_ON(!xp); - err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx); + err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx, NULL, 0); return err; } @@ -217,13 +356,14 @@ int selinux_xfrm_policy_delete(struct xfrm_policy *xp) * LSM hook implementation that allocs and transfers sec_ctx spec to * xfrm_state. */ -int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uctx) +int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uctx, + struct xfrm_sec_ctx *pol, u32 secid) { int err; BUG_ON(!x); - err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx); + err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, pol, secid); return err; } @@ -329,38 +469,30 @@ int selinux_xfrm_state_delete(struct xfrm_state *x) * we need to check for unlabelled access since this may not have * gone thru the IPSec process. */ -int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb) +int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb, + struct avc_audit_data *ad) { int i, rc = 0; struct sec_path *sp; + u32 sel_sid = SECINITSID_UNLABELED; sp = skb->sp; if (sp) { - /* - * __xfrm_policy_check does not approve unless xfrm_policy_ok - * says that spi's match for policy and the socket. - * - * Only need to verify the existence of an authorizable sp. - */ for (i = 0; i < sp->len; i++) { struct xfrm_state *x = sp->xvec[i]; - if (x && selinux_authorizable_xfrm(x)) - goto accept; + if (x && selinux_authorizable_xfrm(x)) { + struct xfrm_sec_ctx *ctx = x->security; + sel_sid = ctx->ctx_sid; + break; + } } } - /* check SELinux sock for unlabelled access */ - rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION, - ASSOCIATION__RECVFROM, NULL); - if (rc) - goto drop; - -accept: - return 0; + rc = avc_has_perm(isec_sid, sel_sid, SECCLASS_ASSOCIATION, + ASSOCIATION__RECVFROM, ad); -drop: return rc; } @@ -371,7 +503,8 @@ drop: * If we do have a authorizable security association, then it has already been * checked in xfrm_policy_lookup hook. */ -int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb) +int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb, + struct avc_audit_data *ad) { struct dst_entry *dst; int rc = 0; @@ -391,7 +524,7 @@ int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb) } rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION, - ASSOCIATION__SENDTO, NULL); + ASSOCIATION__SENDTO, ad); out: return rc; } -- cgit v1.2.3 From beb8d13bed80f8388f1a9a107d07ddd342e627e8 Mon Sep 17 00:00:00 2001 From: Venkat Yekkirala Date: Fri, 4 Aug 2006 23:12:42 -0700 Subject: [MLSXFRM]: Add flow labeling This labels the flows that could utilize IPSec xfrms at the points the flows are defined so that IPSec policy and SAs at the right label can be used. The following protos are currently not handled, but they should continue to be able to use single-labeled IPSec like they currently do. ipmr ip_gre ipip igmp sit sctp ip6_tunnel (IPv6 over IPv6 tunnel device) decnet Signed-off-by: Venkat Yekkirala Signed-off-by: David S. Miller --- security/selinux/xfrm.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'security/selinux/xfrm.c') diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c index a502b0540e3d..c750ef7af66f 100644 --- a/security/selinux/xfrm.c +++ b/security/selinux/xfrm.c @@ -158,11 +158,11 @@ int selinux_xfrm_flow_state_match(struct flowi *fl, struct xfrm_state *xfrm) * LSM hook implementation that determines the sid for the session. */ -int selinux_xfrm_decode_session(struct sk_buff *skb, struct flowi *fl) +int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall) { struct sec_path *sp; - fl->secid = SECSID_NULL; + *sid = SECSID_NULL; if (skb == NULL) return 0; @@ -177,10 +177,13 @@ int selinux_xfrm_decode_session(struct sk_buff *skb, struct flowi *fl) struct xfrm_sec_ctx *ctx = x->security; if (!sid_set) { - fl->secid = ctx->ctx_sid; + *sid = ctx->ctx_sid; sid_set = 1; + + if (!ckall) + break; } - else if (fl->secid != ctx->ctx_sid) + else if (*sid != ctx->ctx_sid) return -EINVAL; } } -- cgit v1.2.3 From cb969f072b6d67770b559617f14e767f47e77ece Mon Sep 17 00:00:00 2001 From: Venkat Yekkirala Date: Mon, 24 Jul 2006 23:32:20 -0700 Subject: [MLSXFRM]: Default labeling of socket specific IPSec policies This defaults the label of socket-specific IPSec policies to be the same as the socket they are set on. Signed-off-by: Venkat Yekkirala Signed-off-by: David S. Miller --- security/selinux/xfrm.c | 33 ++++++++++++++++++++++----------- 1 file changed, 22 insertions(+), 11 deletions(-) (limited to 'security/selinux/xfrm.c') diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c index c750ef7af66f..d3690f985135 100644 --- a/security/selinux/xfrm.c +++ b/security/selinux/xfrm.c @@ -208,10 +208,8 @@ static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp, BUG_ON(uctx && pol); - if (pol) - goto from_policy; - - BUG_ON(!uctx); + if (!uctx) + goto not_from_user; if (uctx->ctx_doi != XFRM_SC_ALG_SELINUX) return -EINVAL; @@ -251,11 +249,14 @@ static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp, return rc; -from_policy: - BUG_ON(!pol); - rc = security_sid_mls_copy(pol->ctx_sid, sid, &ctx_sid); - if (rc) - goto out; +not_from_user: + if (pol) { + rc = security_sid_mls_copy(pol->ctx_sid, sid, &ctx_sid); + if (rc) + goto out; + } + else + ctx_sid = sid; rc = security_sid_to_context(ctx_sid, &ctx_str, &str_len); if (rc) @@ -293,13 +294,23 @@ out2: * LSM hook implementation that allocs and transfers uctx spec to * xfrm_policy. */ -int selinux_xfrm_policy_alloc(struct xfrm_policy *xp, struct xfrm_user_sec_ctx *uctx) +int selinux_xfrm_policy_alloc(struct xfrm_policy *xp, + struct xfrm_user_sec_ctx *uctx, struct sock *sk) { int err; + u32 sid; BUG_ON(!xp); + BUG_ON(uctx && sk); + + if (sk) { + struct sk_security_struct *ssec = sk->sk_security; + sid = ssec->sid; + } + else + sid = SECSID_NULL; - err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx, NULL, 0); + err = selinux_xfrm_sec_ctx_alloc(&xp->security, uctx, NULL, sid); return err; } -- cgit v1.2.3 From 4237c75c0a35535d7f9f2bfeeb4b4df1e068a0bf Mon Sep 17 00:00:00 2001 From: Venkat Yekkirala Date: Mon, 24 Jul 2006 23:32:50 -0700 Subject: [MLSXFRM]: Auto-labeling of child sockets This automatically labels the TCP, Unix stream, and dccp child sockets as well as openreqs to be at the same MLS level as the peer. This will result in the selection of appropriately labeled IPSec Security Associations. This also uses the sock's sid (as opposed to the isec sid) in SELinux enforcement of secmark in rcv_skb and postroute_last hooks. Signed-off-by: Venkat Yekkirala Signed-off-by: David S. Miller --- security/selinux/xfrm.c | 1 - 1 file changed, 1 deletion(-) (limited to 'security/selinux/xfrm.c') diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c index d3690f985135..3e742b850af6 100644 --- a/security/selinux/xfrm.c +++ b/security/selinux/xfrm.c @@ -271,7 +271,6 @@ not_from_user: goto out; } - ctx->ctx_doi = XFRM_SC_DOI_LSM; ctx->ctx_alg = XFRM_SC_ALG_SELINUX; ctx->ctx_sid = ctx_sid; -- cgit v1.2.3