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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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df71837d50
This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
96 lines
1.9 KiB
C
96 lines
1.9 KiB
C
/*
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*
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* Generic internet FLOW.
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*
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*/
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#ifndef _NET_FLOW_H
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#define _NET_FLOW_H
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#include <linux/in6.h>
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#include <asm/atomic.h>
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struct flowi {
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int oif;
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int iif;
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union {
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struct {
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__u32 daddr;
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__u32 saddr;
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__u32 fwmark;
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__u8 tos;
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__u8 scope;
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} ip4_u;
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struct {
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struct in6_addr daddr;
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struct in6_addr saddr;
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__u32 flowlabel;
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} ip6_u;
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struct {
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__u16 daddr;
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__u16 saddr;
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__u32 fwmark;
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__u8 scope;
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} dn_u;
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} nl_u;
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#define fld_dst nl_u.dn_u.daddr
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#define fld_src nl_u.dn_u.saddr
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#define fld_fwmark nl_u.dn_u.fwmark
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#define fld_scope nl_u.dn_u.scope
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#define fl6_dst nl_u.ip6_u.daddr
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#define fl6_src nl_u.ip6_u.saddr
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#define fl6_flowlabel nl_u.ip6_u.flowlabel
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#define fl4_dst nl_u.ip4_u.daddr
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#define fl4_src nl_u.ip4_u.saddr
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#define fl4_fwmark nl_u.ip4_u.fwmark
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#define fl4_tos nl_u.ip4_u.tos
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#define fl4_scope nl_u.ip4_u.scope
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__u8 proto;
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__u8 flags;
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#define FLOWI_FLAG_MULTIPATHOLDROUTE 0x01
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union {
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struct {
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__u16 sport;
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__u16 dport;
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} ports;
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struct {
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__u8 type;
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__u8 code;
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} icmpt;
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struct {
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__u16 sport;
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__u16 dport;
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__u8 objnum;
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__u8 objnamel; /* Not 16 bits since max val is 16 */
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__u8 objname[16]; /* Not zero terminated */
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} dnports;
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__u32 spi;
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} uli_u;
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#define fl_ip_sport uli_u.ports.sport
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#define fl_ip_dport uli_u.ports.dport
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#define fl_icmp_type uli_u.icmpt.type
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#define fl_icmp_code uli_u.icmpt.code
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#define fl_ipsec_spi uli_u.spi
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} __attribute__((__aligned__(BITS_PER_LONG/8)));
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#define FLOW_DIR_IN 0
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#define FLOW_DIR_OUT 1
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#define FLOW_DIR_FWD 2
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struct sock;
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typedef void (*flow_resolve_t)(struct flowi *key, u32 sk_sid, u16 family, u8 dir,
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void **objp, atomic_t **obj_refp);
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extern void *flow_cache_lookup(struct flowi *key, u32 sk_sid, u16 family, u8 dir,
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flow_resolve_t resolver);
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extern void flow_cache_flush(void);
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extern atomic_t flow_cache_genid;
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#endif
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