From: Eric Paris <eparis@redhat.com> Subject: [RHEL 5.1 PATCH] BZ 228557 xfrm_policy delete security check misplaced Date: Thu, 05 Apr 2007 15:24:42 -0400 Bugzilla: 228557 Message-Id: <1175801082.20396.184.camel@localhost.localdomain> Changelog: [net] xfrm_policy delete security check misplaced BZ 228557 The security hooks to check permissions to remove an xfrm_policy were actually done after the policy was removed. Since the unlinking and deletion are done in xfrm_policy_by* functions this moves the hooks inside those 2 functions. There we have all the information needed to do the security check and it can be done before the deletion. Since auditing requires the result of that security check err has to be passed back and forth from the xfrm_policy_by* functions. This patch also fixes a bug where a deletion that failed the security check could cause improper accounting on the xfrm_policy (xfrm_get_policy didn't have a put on the exit path for the hold taken by xfrm_policy_by*) It also fixes the return code when no policy is found in xfrm_add_pol_expire. In old code err wasn't used before the return when no policy is found and so the initialization would cause err to be ENOENT. But since err has since been used above when we don't get a policy back from the xfrm_policy_by* function we would always return 0 instead of the intended ENOENT. Also fixed some white space damage in the same area. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=ef41aaa0b755f479012341ac11db9ca5b8928d98 Has been in the LSPP kernel and no problems have arisen. Testing was done by IBM to show that before this patch deletions 'denied' by security policy were being allowed and after the patch things were properly enforced. diff -Naupr linux-2.6.18.i386.orig/include/net/xfrm.h linux-2.6.18.i386/include/net/xfrm.h --- linux-2.6.18.i386.orig/include/net/xfrm.h 2007-02-22 16:27:13.000000000 -0500 +++ linux-2.6.18.i386/include/net/xfrm.h 2007-02-22 17:09:43.000000000 -0500 @@ -964,8 +964,9 @@ struct xfrm_policy *xfrm_policy_alloc(gf extern int xfrm_policy_walk(int (*func)(struct xfrm_policy *, int, int, void*), void *); int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl); struct xfrm_policy *xfrm_policy_bysel_ctx(int dir, struct xfrm_selector *sel, - struct xfrm_sec_ctx *ctx, int delete); -struct xfrm_policy *xfrm_policy_byid(int dir, u32 id, int delete); + struct xfrm_sec_ctx *ctx, int delete, + int *err); +struct xfrm_policy *xfrm_policy_byid(int dir, u32 id, int delete, int *err); void xfrm_policy_flush(struct xfrm_audit *audit_info); u32 xfrm_get_acqseq(void); void xfrm_alloc_spi(struct xfrm_state *x, u32 minspi, u32 maxspi); diff -Naupr linux-2.6.18.i386.orig/net/key/af_key.c linux-2.6.18.i386/net/key/af_key.c --- linux-2.6.18.i386.orig/net/key/af_key.c 2007-02-22 16:24:53.000000000 -0500 +++ linux-2.6.18.i386/net/key/af_key.c 2007-02-22 17:27:14.000000000 -0500 @@ -2282,14 +2282,13 @@ static int pfkey_spddelete(struct sock * return err; } - xp = xfrm_policy_bysel_ctx(pol->sadb_x_policy_dir-1, &sel, tmp.security, 1); + xp = xfrm_policy_bysel_ctx(pol->sadb_x_policy_dir-1, &sel, tmp.security, + 1, &err); security_xfrm_policy_free(&tmp); if (xp == NULL) return -ENOENT; - err = security_xfrm_policy_delete(xp); - xfrm_audit_log(audit_get_loginuid(current->audit_context), 0, AUDIT_MAC_IPSEC_DELSPD, err ? 0 : 1, xp, NULL); @@ -2350,11 +2349,12 @@ static int pfkey_spdget(struct sock *sk, return -EINVAL; xp = xfrm_policy_byid(dir, pol->sadb_x_policy_id, - hdr->sadb_msg_type == SADB_X_SPDDELETE2); + hdr->sadb_msg_type == SADB_X_SPDDELETE2, &err); if (xp == NULL) return -ENOENT; - err = 0; + if (err) + goto out; c.seq = hdr->sadb_msg_seq; c.pid = hdr->sadb_msg_pid; @@ -2366,6 +2366,7 @@ static int pfkey_spdget(struct sock *sk, err = key_pol_get_resp(sk, xp, hdr, dir); } +out: xfrm_pol_put(xp); return err; } diff -Naupr linux-2.6.18.i386.orig/net/xfrm/xfrm_policy.c linux-2.6.18.i386/net/xfrm/xfrm_policy.c --- linux-2.6.18.i386.orig/net/xfrm/xfrm_policy.c 2007-02-22 16:24:56.000000000 -0500 +++ linux-2.6.18.i386/net/xfrm/xfrm_policy.c 2007-02-22 17:18:33.000000000 -0500 @@ -495,16 +495,23 @@ int xfrm_policy_insert(int dir, struct x EXPORT_SYMBOL(xfrm_policy_insert); struct xfrm_policy *xfrm_policy_bysel_ctx(int dir, struct xfrm_selector *sel, - struct xfrm_sec_ctx *ctx, int delete) + struct xfrm_sec_ctx *ctx, int delete, + int *err) { struct xfrm_policy *pol, **p; + *err = 0; write_lock_bh(&xfrm_policy_lock); for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) { if ((memcmp(sel, &pol->selector, sizeof(*sel)) == 0) && (xfrm_sec_ctx_match(ctx, pol->security))) { xfrm_pol_hold(pol); if (delete) + *err = security_xfrm_policy_delete(pol); + if (*err) { + write_unlock_bh(&xfrm_policy_lock); + return pol; + } *p = pol->next; break; } @@ -519,15 +526,21 @@ struct xfrm_policy *xfrm_policy_bysel_ct } EXPORT_SYMBOL(xfrm_policy_bysel_ctx); -struct xfrm_policy *xfrm_policy_byid(int dir, u32 id, int delete) +struct xfrm_policy *xfrm_policy_byid(int dir, u32 id, int delete, int *err) { struct xfrm_policy *pol, **p; + *err = 0; write_lock_bh(&xfrm_policy_lock); for (p = &xfrm_policy_list[dir]; (pol=*p)!=NULL; p = &pol->next) { if (pol->index == id) { xfrm_pol_hold(pol); if (delete) + *err = security_xfrm_policy_delete(pol); + if (*err) { + write_unlock_bh(&xfrm_policy_lock); + return pol; + } *p = pol->next; break; } diff -Naupr linux-2.6.18.i386.orig/net/xfrm/xfrm_user.c linux-2.6.18.i386/net/xfrm/xfrm_user.c --- linux-2.6.18.i386.orig/net/xfrm/xfrm_user.c 2007-02-22 16:24:56.000000000 -0500 +++ linux-2.6.18.i386/net/xfrm/xfrm_user.c 2007-02-22 17:28:01.000000000 -0500 @@ -1046,7 +1046,7 @@ static int xfrm_get_policy(struct sk_buf return err; if (p->index) - xp = xfrm_policy_byid(p->dir, p->index, delete); + xp = xfrm_policy_byid(p->dir, p->index, delete, &err); else { struct rtattr **rtattrs = (struct rtattr **)xfrma; struct rtattr *rt = rtattrs[XFRMA_SEC_CTX-1]; @@ -1063,7 +1063,8 @@ static int xfrm_get_policy(struct sk_buf if ((err = security_xfrm_policy_alloc(&tmp, uctx))) return err; } - xp = xfrm_policy_bysel_ctx(p->dir, &p->sel, tmp.security, delete); + xp = xfrm_policy_bysel_ctx(p->dir, &p->sel, tmp.security, + delete, &err); security_xfrm_policy_free(&tmp); } if (xp == NULL) @@ -1081,8 +1082,6 @@ static int xfrm_get_policy(struct sk_buf MSG_DONTWAIT); } } else { - err = security_xfrm_policy_delete(xp); - xfrm_audit_log(NETLINK_CB(skb).loginuid, NETLINK_CB(skb).sid, AUDIT_MAC_IPSEC_DELSPD, err ? 0 : 1, xp, NULL); @@ -1096,9 +1095,8 @@ static int xfrm_get_policy(struct sk_buf km_policy_notify(xp, p->dir, &c); } - xfrm_pol_put(xp); - out: + xfrm_pol_put(xp); return err; } @@ -1273,10 +1271,10 @@ static int xfrm_add_pol_expire(struct sk struct xfrm_policy *xp; struct xfrm_user_polexpire *up = NLMSG_DATA(nlh); struct xfrm_userpolicy_info *p = &up->pol; - int err = -ENOENT; + int err = 0; if (p->index) - xp = xfrm_policy_byid(p->dir, p->index, 0); + xp = xfrm_policy_byid(p->dir, p->index, 0, &err); else { struct rtattr **rtattrs = (struct rtattr **)xfrma; struct rtattr *rt = rtattrs[XFRMA_SEC_CTX-1]; @@ -1293,13 +1291,13 @@ static int xfrm_add_pol_expire(struct sk if ((err = security_xfrm_policy_alloc(&tmp, uctx))) return err; } - xp = xfrm_policy_bysel_ctx(p->dir, &p->sel, tmp.security, 0); + xp = xfrm_policy_bysel_ctx(p->dir, &p->sel, tmp.security, 0, &err); security_xfrm_policy_free(&tmp); } if (xp == NULL) - return err; - read_lock(&xp->lock); + return -ENOENT; + read_lock(&xp->lock); if (xp->dead) { read_unlock(&xp->lock); goto out;