diff options
Diffstat (limited to 'security/selinux/xfrm.c')
| -rw-r--r-- | security/selinux/xfrm.c | 495 |
1 files changed, 238 insertions, 257 deletions
diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c index fff78d3b51a..98b042630a9 100644 --- a/security/selinux/xfrm.c +++ b/security/selinux/xfrm.c @@ -46,7 +46,7 @@ #include <net/xfrm.h> #include <net/checksum.h> #include <net/udp.h> -#include <asm/atomic.h> +#include <linux/atomic.h> #include "avc.h" #include "objsec.h" @@ -56,7 +56,7 @@ atomic_t selinux_xfrm_refcount = ATOMIC_INIT(0); /* - * Returns true if an LSM/SELinux context + * Returns true if the context is an LSM/SELinux context. */ static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx) { @@ -66,7 +66,7 @@ static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx) } /* - * Returns true if the xfrm contains a security blob for SELinux + * Returns true if the xfrm contains a security blob for SELinux. */ static inline int selinux_authorizable_xfrm(struct xfrm_state *x) { @@ -74,48 +74,112 @@ static inline int selinux_authorizable_xfrm(struct xfrm_state *x) } /* - * LSM hook implementation that authorizes that a flow can use - * a xfrm policy rule. + * Allocates a xfrm_sec_state and populates it using the supplied security + * xfrm_user_sec_ctx context. */ -int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir) +static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp, + struct xfrm_user_sec_ctx *uctx, + gfp_t gfp) { int rc; - u32 sel_sid; + const struct task_security_struct *tsec = current_security(); + struct xfrm_sec_ctx *ctx = NULL; + u32 str_len; - /* Context sid is either set to label or ANY_ASSOC */ - if (ctx) { - if (!selinux_authorizable_ctx(ctx)) - return -EINVAL; - - sel_sid = ctx->ctx_sid; - } else - /* - * All flows should be treated as polmatch'ing an - * otherwise applicable "non-labeled" policy. This - * would prevent inadvertent "leaks". - */ - return 0; + if (ctxp == NULL || uctx == NULL || + uctx->ctx_doi != XFRM_SC_DOI_LSM || + uctx->ctx_alg != XFRM_SC_ALG_SELINUX) + return -EINVAL; + + str_len = uctx->ctx_len; + if (str_len >= PAGE_SIZE) + return -ENOMEM; + + ctx = kmalloc(sizeof(*ctx) + str_len + 1, gfp); + if (!ctx) + return -ENOMEM; + + ctx->ctx_doi = XFRM_SC_DOI_LSM; + ctx->ctx_alg = XFRM_SC_ALG_SELINUX; + ctx->ctx_len = str_len; + memcpy(ctx->ctx_str, &uctx[1], str_len); + ctx->ctx_str[str_len] = '\0'; + rc = security_context_to_sid(ctx->ctx_str, str_len, &ctx->ctx_sid, gfp); + if (rc) + goto err; - rc = avc_has_perm(fl_secid, sel_sid, SECCLASS_ASSOCIATION, - ASSOCIATION__POLMATCH, - NULL); + rc = avc_has_perm(tsec->sid, ctx->ctx_sid, + SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT, NULL); + if (rc) + goto err; - if (rc == -EACCES) - return -ESRCH; + *ctxp = ctx; + atomic_inc(&selinux_xfrm_refcount); + return 0; +err: + kfree(ctx); return rc; } /* + * Free the xfrm_sec_ctx structure. + */ +static void selinux_xfrm_free(struct xfrm_sec_ctx *ctx) +{ + if (!ctx) + return; + + atomic_dec(&selinux_xfrm_refcount); + kfree(ctx); +} + +/* + * Authorize the deletion of a labeled SA or policy rule. + */ +static int selinux_xfrm_delete(struct xfrm_sec_ctx *ctx) +{ + const struct task_security_struct *tsec = current_security(); + + if (!ctx) + return 0; + + return avc_has_perm(tsec->sid, ctx->ctx_sid, + SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT, + NULL); +} + +/* + * LSM hook implementation that authorizes that a flow can use a xfrm policy + * rule. + */ +int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir) +{ + int rc; + + /* All flows should be treated as polmatch'ing an otherwise applicable + * "non-labeled" policy. This would prevent inadvertent "leaks". */ + if (!ctx) + return 0; + + /* Context sid is either set to label or ANY_ASSOC */ + if (!selinux_authorizable_ctx(ctx)) + return -EINVAL; + + rc = avc_has_perm(fl_secid, ctx->ctx_sid, + SECCLASS_ASSOCIATION, ASSOCIATION__POLMATCH, NULL); + return (rc == -EACCES ? -ESRCH : 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) +int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x, + struct xfrm_policy *xp, + const struct flowi *fl) { u32 state_sid; - int rc; if (!xp->security) if (x->security) @@ -135,189 +199,115 @@ int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x, struct xfrm_policy * state_sid = x->security->ctx_sid; - if (fl->secid != state_sid) + if (fl->flowi_secid != state_sid) return 0; - rc = avc_has_perm(fl->secid, state_sid, SECCLASS_ASSOCIATION, - ASSOCIATION__SENDTO, - NULL)? 0:1; - - /* - * We don't need a separate SA Vs. policy polmatch check - * since the SA is now of the same label as the flow and - * a flow Vs. policy polmatch check had already happened - * in selinux_xfrm_policy_lookup() above. - */ - - return rc; + /* We don't need a separate SA Vs. policy polmatch check since the SA + * is now of the same label as the flow and a flow Vs. policy polmatch + * check had already happened in selinux_xfrm_policy_lookup() above. */ + return (avc_has_perm(fl->flowi_secid, state_sid, + SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO, + NULL) ? 0 : 1); } -/* - * LSM hook implementation that checks and/or returns the xfrm sid for the - * incoming packet. - */ - -int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall) +static u32 selinux_xfrm_skb_sid_egress(struct sk_buff *skb) { - struct sec_path *sp; + struct dst_entry *dst = skb_dst(skb); + struct xfrm_state *x; - *sid = SECSID_NULL; + if (dst == NULL) + return SECSID_NULL; + x = dst->xfrm; + if (x == NULL || !selinux_authorizable_xfrm(x)) + return SECSID_NULL; - if (skb == NULL) - return 0; + return x->security->ctx_sid; +} + +static int selinux_xfrm_skb_sid_ingress(struct sk_buff *skb, + u32 *sid, int ckall) +{ + u32 sid_session = SECSID_NULL; + struct sec_path *sp = skb->sp; - sp = skb->sp; if (sp) { - int i, sid_set = 0; + int i; - for (i = sp->len-1; i >= 0; i--) { + 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) { - *sid = ctx->ctx_sid; - sid_set = 1; - + if (sid_session == SECSID_NULL) { + sid_session = ctx->ctx_sid; if (!ckall) - break; - } else if (*sid != ctx->ctx_sid) + goto out; + } else if (sid_session != ctx->ctx_sid) { + *sid = SECSID_NULL; return -EINVAL; + } } } } +out: + *sid = sid_session; return 0; } /* - * Security blob allocation for xfrm_policy and xfrm_state - * CTX does not have a meaningful value on input + * LSM hook implementation that checks and/or returns the xfrm sid for the + * incoming packet. */ -static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp, - struct xfrm_user_sec_ctx *uctx, u32 sid) +int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall) { - int rc = 0; - const struct task_security_struct *tsec = current_security(); - struct xfrm_sec_ctx *ctx = NULL; - char *ctx_str = NULL; - u32 str_len; - - BUG_ON(uctx && sid); - - if (!uctx) - goto not_from_user; - - if (uctx->ctx_doi != XFRM_SC_ALG_SELINUX) - return -EINVAL; - - str_len = uctx->ctx_len; - if (str_len >= PAGE_SIZE) - return -ENOMEM; - - *ctxp = ctx = kmalloc(sizeof(*ctx) + - str_len + 1, - GFP_KERNEL); - - if (!ctx) - return -ENOMEM; - - ctx->ctx_doi = uctx->ctx_doi; - ctx->ctx_len = str_len; - ctx->ctx_alg = uctx->ctx_alg; - - memcpy(ctx->ctx_str, - uctx+1, - str_len); - ctx->ctx_str[str_len] = 0; - rc = security_context_to_sid(ctx->ctx_str, - str_len, - &ctx->ctx_sid); - - if (rc) - goto out; - - /* - * Does the subject have permission to set security context? - */ - rc = avc_has_perm(tsec->sid, ctx->ctx_sid, - SECCLASS_ASSOCIATION, - ASSOCIATION__SETCONTEXT, NULL); - if (rc) - goto out; - - return rc; - -not_from_user: - rc = security_sid_to_context(sid, &ctx_str, &str_len); - if (rc) - goto out; - - *ctxp = ctx = kmalloc(sizeof(*ctx) + - str_len, - GFP_ATOMIC); - - if (!ctx) { - rc = -ENOMEM; - goto out; + if (skb == NULL) { + *sid = SECSID_NULL; + return 0; } + return selinux_xfrm_skb_sid_ingress(skb, sid, ckall); +} - ctx->ctx_doi = XFRM_SC_DOI_LSM; - ctx->ctx_alg = XFRM_SC_ALG_SELINUX; - ctx->ctx_sid = sid; - ctx->ctx_len = str_len; - memcpy(ctx->ctx_str, - ctx_str, - str_len); +int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid) +{ + int rc; - goto out2; + rc = selinux_xfrm_skb_sid_ingress(skb, sid, 0); + if (rc == 0 && *sid == SECSID_NULL) + *sid = selinux_xfrm_skb_sid_egress(skb); -out: - *ctxp = NULL; - kfree(ctx); -out2: - kfree(ctx_str); return rc; } /* - * LSM hook implementation that allocs and transfers uctx spec to - * xfrm_policy. + * LSM hook implementation that allocs and transfers uctx spec to xfrm_policy. */ int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp, - struct xfrm_user_sec_ctx *uctx) + struct xfrm_user_sec_ctx *uctx, + gfp_t gfp) { - int err; - - BUG_ON(!uctx); - - err = selinux_xfrm_sec_ctx_alloc(ctxp, uctx, 0); - if (err == 0) - atomic_inc(&selinux_xfrm_refcount); - - return err; + return selinux_xfrm_alloc_user(ctxp, uctx, gfp); } - /* - * LSM hook implementation that copies security data structure from old to - * new for policy cloning. + * LSM hook implementation that copies security data structure from old to new + * for policy cloning. */ int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx, struct xfrm_sec_ctx **new_ctxp) { struct xfrm_sec_ctx *new_ctx; - if (old_ctx) { - new_ctx = kmalloc(sizeof(*old_ctx) + old_ctx->ctx_len, - GFP_KERNEL); - if (!new_ctx) - return -ENOMEM; + if (!old_ctx) + return 0; + + new_ctx = kmemdup(old_ctx, sizeof(*old_ctx) + old_ctx->ctx_len, + GFP_ATOMIC); + if (!new_ctx) + return -ENOMEM; + atomic_inc(&selinux_xfrm_refcount); + *new_ctxp = new_ctx; - memcpy(new_ctx, old_ctx, sizeof(*new_ctx)); - memcpy(new_ctx->ctx_str, old_ctx->ctx_str, new_ctx->ctx_len); - *new_ctxp = new_ctx; - } return 0; } @@ -326,7 +316,7 @@ int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx, */ void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx) { - kfree(ctx); + selinux_xfrm_free(ctx); } /* @@ -334,35 +324,58 @@ void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx) */ int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx) { - const struct task_security_struct *tsec = current_security(); - int rc = 0; - - if (ctx) { - rc = avc_has_perm(tsec->sid, ctx->ctx_sid, - SECCLASS_ASSOCIATION, - ASSOCIATION__SETCONTEXT, NULL); - if (rc == 0) - atomic_dec(&selinux_xfrm_refcount); - } + return selinux_xfrm_delete(ctx); +} - return rc; +/* + * LSM hook implementation that allocates a xfrm_sec_state, populates it using + * the supplied security context, and assigns it to the xfrm_state. + */ +int selinux_xfrm_state_alloc(struct xfrm_state *x, + struct xfrm_user_sec_ctx *uctx) +{ + return selinux_xfrm_alloc_user(&x->security, uctx, GFP_KERNEL); } /* - * LSM hook implementation that allocs and transfers sec_ctx spec to - * xfrm_state. + * LSM hook implementation that allocates a xfrm_sec_state and populates based + * on a secid. */ -int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uctx, - u32 secid) +int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x, + struct xfrm_sec_ctx *polsec, u32 secid) { - int err; + int rc; + struct xfrm_sec_ctx *ctx; + char *ctx_str = NULL; + int str_len; + + if (!polsec) + return 0; - BUG_ON(!x); + if (secid == 0) + return -EINVAL; + + rc = security_sid_to_context(secid, &ctx_str, &str_len); + if (rc) + return rc; + + 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 = secid; + ctx->ctx_len = str_len; + memcpy(ctx->ctx_str, ctx_str, str_len); - err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, secid); - if (err == 0) - atomic_inc(&selinux_xfrm_refcount); - return err; + x->security = ctx; + atomic_inc(&selinux_xfrm_refcount); +out: + kfree(ctx_str); + return rc; } /* @@ -370,28 +383,15 @@ int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uct */ void selinux_xfrm_state_free(struct xfrm_state *x) { - struct xfrm_sec_ctx *ctx = x->security; - kfree(ctx); + selinux_xfrm_free(x->security); } - /* - * LSM hook implementation that authorizes deletion of labeled SAs. - */ +/* + * LSM hook implementation that authorizes deletion of labeled SAs. + */ int selinux_xfrm_state_delete(struct xfrm_state *x) { - const struct task_security_struct *tsec = current_security(); - struct xfrm_sec_ctx *ctx = x->security; - int rc = 0; - - if (ctx) { - rc = avc_has_perm(tsec->sid, ctx->ctx_sid, - SECCLASS_ASSOCIATION, - ASSOCIATION__SETCONTEXT, NULL); - if (rc == 0) - atomic_dec(&selinux_xfrm_refcount); - } - - return rc; + return selinux_xfrm_delete(x->security); } /* @@ -401,14 +401,12 @@ 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, - struct common_audit_data *ad) +int selinux_xfrm_sock_rcv_skb(u32 sk_sid, struct sk_buff *skb, + struct common_audit_data *ad) { - int i, rc = 0; - struct sec_path *sp; - u32 sel_sid = SECINITSID_UNLABELED; - - sp = skb->sp; + int i; + struct sec_path *sp = skb->sp; + u32 peer_sid = SECINITSID_UNLABELED; if (sp) { for (i = 0; i < sp->len; i++) { @@ -416,23 +414,17 @@ int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb, if (x && selinux_authorizable_xfrm(x)) { struct xfrm_sec_ctx *ctx = x->security; - sel_sid = ctx->ctx_sid; + peer_sid = ctx->ctx_sid; break; } } } - /* - * This check even when there's no association involved is - * intended, according to Trent Jaeger, to make sure a - * process can't engage in non-ipsec communication unless - * explicitly allowed by policy. - */ - - rc = avc_has_perm(isec_sid, sel_sid, SECCLASS_ASSOCIATION, - ASSOCIATION__RECVFROM, ad); - - return rc; + /* This check even when there's no association involved is intended, + * according to Trent Jaeger, to make sure a process can't engage in + * non-IPsec communication unless explicitly allowed by policy. */ + return avc_has_perm(sk_sid, peer_sid, + SECCLASS_ASSOCIATION, ASSOCIATION__RECVFROM, ad); } /* @@ -442,49 +434,38 @@ int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb, * If we do have a authorizable security association, then it has already been * checked in the selinux_xfrm_state_pol_flow_match hook above. */ -int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb, - struct common_audit_data *ad, u8 proto) +int selinux_xfrm_postroute_last(u32 sk_sid, struct sk_buff *skb, + struct common_audit_data *ad, u8 proto) { struct dst_entry *dst; - int rc = 0; - - dst = skb_dst(skb); - - if (dst) { - struct dst_entry *dst_test; - - for (dst_test = dst; dst_test != NULL; - dst_test = dst_test->child) { - struct xfrm_state *x = dst_test->xfrm; - - if (x && selinux_authorizable_xfrm(x)) - goto out; - } - } switch (proto) { case IPPROTO_AH: case IPPROTO_ESP: case IPPROTO_COMP: - /* - * We should have already seen this packet once before - * it underwent xfrm(s). No need to subject it to the - * unlabeled check. - */ - goto out; + /* We should have already seen this packet once before it + * underwent xfrm(s). No need to subject it to the unlabeled + * check. */ + return 0; default: break; } - /* - * This check even when there's no association involved is - * intended, according to Trent Jaeger, to make sure a - * process can't engage in non-ipsec communication unless - * explicitly allowed by policy. - */ + dst = skb_dst(skb); + if (dst) { + struct dst_entry *iter; + + for (iter = dst; iter != NULL; iter = iter->child) { + struct xfrm_state *x = iter->xfrm; - rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION, - ASSOCIATION__SENDTO, ad); -out: - return rc; + if (x && selinux_authorizable_xfrm(x)) + return 0; + } + } + + /* This check even when there's no association involved is intended, + * according to Trent Jaeger, to make sure a process can't engage in + * non-IPsec communication unless explicitly allowed by policy. */ + return avc_has_perm(sk_sid, SECINITSID_UNLABELED, + SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO, ad); } |