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[NETLINK]: Encapsulate eff_cap usage within security framework.
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This patch encapsulates the usage of eff_cap (in netlink_skb_params) within
the security framework by extending security_netlink_recv to include a required
capability parameter and converting all direct usage of eff_caps outside
of the lsm modules to use the interface.  It also updates the SELinux
implementation of the security_netlink_send and security_netlink_recv
hooks to take advantage of the sid in the netlink_skb_params struct.
This also enables SELinux to perform auditing of netlink capability checks.
Please apply, for 2.6.18 if possible.

Signed-off-by: Darrel Goeddel <dgoeddel@trustedcs.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by:  James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Darrel Goeddel authored and David S. Miller committed Jun 29, 2006
1 parent 576a30e commit c7bdb54
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Showing 12 changed files with 35 additions and 34 deletions.
13 changes: 7 additions & 6 deletions include/linux/security.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,7 @@ struct xfrm_state;
struct xfrm_user_sec_ctx;

extern int cap_netlink_send(struct sock *sk, struct sk_buff *skb);
extern int cap_netlink_recv(struct sk_buff *skb);
extern int cap_netlink_recv(struct sk_buff *skb, int cap);

/*
* Values used in the task_security_ops calls
Expand Down Expand Up @@ -656,6 +656,7 @@ struct swap_info_struct;
* Check permission before processing the received netlink message in
* @skb.
* @skb contains the sk_buff structure for the netlink message.
* @cap indicates the capability required
* Return 0 if permission is granted.
*
* Security hooks for Unix domain networking.
Expand Down Expand Up @@ -1266,7 +1267,7 @@ struct security_operations {
struct sembuf * sops, unsigned nsops, int alter);

int (*netlink_send) (struct sock * sk, struct sk_buff * skb);
int (*netlink_recv) (struct sk_buff * skb);
int (*netlink_recv) (struct sk_buff * skb, int cap);

/* allow module stacking */
int (*register_security) (const char *name,
Expand Down Expand Up @@ -2032,9 +2033,9 @@ static inline int security_netlink_send(struct sock *sk, struct sk_buff * skb)
return security_ops->netlink_send(sk, skb);
}

static inline int security_netlink_recv(struct sk_buff * skb)
static inline int security_netlink_recv(struct sk_buff * skb, int cap)
{
return security_ops->netlink_recv(skb);
return security_ops->netlink_recv(skb, cap);
}

/* prototypes */
Expand Down Expand Up @@ -2670,9 +2671,9 @@ static inline int security_netlink_send (struct sock *sk, struct sk_buff *skb)
return cap_netlink_send (sk, skb);
}

static inline int security_netlink_recv (struct sk_buff *skb)
static inline int security_netlink_recv (struct sk_buff *skb, int cap)
{
return cap_netlink_recv (skb);
return cap_netlink_recv (skb, cap);
}

static inline struct dentry *securityfs_create_dir(const char *name,
Expand Down
8 changes: 4 additions & 4 deletions kernel/audit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -445,7 +445,7 @@ void audit_send_reply(int pid, int seq, int type, int done, int multi,
* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
* control messages.
*/
static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type)
static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
{
int err = 0;

Expand All @@ -459,13 +459,13 @@ static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type)
case AUDIT_DEL:
case AUDIT_DEL_RULE:
case AUDIT_SIGNAL_INFO:
if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL))
if (security_netlink_recv(skb, CAP_AUDIT_CONTROL))
err = -EPERM;
break;
case AUDIT_USER:
case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG:
case AUDIT_FIRST_USER_MSG2...AUDIT_LAST_USER_MSG2:
if (!cap_raised(eff_cap, CAP_AUDIT_WRITE))
if (security_netlink_recv(skb, CAP_AUDIT_WRITE))
err = -EPERM;
break;
default: /* bad msg */
Expand All @@ -488,7 +488,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
char *ctx;
u32 len;

err = audit_netlink_ok(NETLINK_CB(skb).eff_cap, msg_type);
err = audit_netlink_ok(skb, msg_type);
if (err)
return err;

Expand Down
2 changes: 1 addition & 1 deletion net/core/rtnetlink.c
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Original file line number Diff line number Diff line change
Expand Up @@ -663,7 +663,7 @@ rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)
sz_idx = type>>2;
kind = type&3;

if (kind != 2 && security_netlink_recv(skb)) {
if (kind != 2 && security_netlink_recv(skb, CAP_NET_ADMIN)) {
*errp = -EPERM;
return -1;
}
Expand Down
2 changes: 1 addition & 1 deletion net/decnet/netfilter/dn_rtmsg.c
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Original file line number Diff line number Diff line change
Expand Up @@ -107,7 +107,7 @@ static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
return;

if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN))
if (security_netlink_recv(skb, CAP_NET_ADMIN))
RCV_SKB_FAIL(-EPERM);

/* Eventually we might send routing messages too */
Expand Down
2 changes: 1 addition & 1 deletion net/ipv4/netfilter/ip_queue.c
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Original file line number Diff line number Diff line change
Expand Up @@ -515,7 +515,7 @@ ipq_rcv_skb(struct sk_buff *skb)
if (type <= IPQM_BASE)
return;

if (security_netlink_recv(skb))
if (security_netlink_recv(skb, CAP_NET_ADMIN))
RCV_SKB_FAIL(-EPERM);

write_lock_bh(&queue_lock);
Expand Down
2 changes: 1 addition & 1 deletion net/ipv6/netfilter/ip6_queue.c
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Original file line number Diff line number Diff line change
Expand Up @@ -505,7 +505,7 @@ ipq_rcv_skb(struct sk_buff *skb)
if (type <= IPQM_BASE)
return;

if (security_netlink_recv(skb))
if (security_netlink_recv(skb, CAP_NET_ADMIN))
RCV_SKB_FAIL(-EPERM);

write_lock_bh(&queue_lock);
Expand Down
2 changes: 1 addition & 1 deletion net/netfilter/nfnetlink.c
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Original file line number Diff line number Diff line change
Expand Up @@ -229,7 +229,7 @@ static int nfnetlink_rcv_msg(struct sk_buff *skb,
NFNL_SUBSYS_ID(nlh->nlmsg_type),
NFNL_MSG_TYPE(nlh->nlmsg_type));

if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN)) {
if (security_netlink_recv(skb, CAP_NET_ADMIN)) {
DEBUGP("missing CAP_NET_ADMIN\n");
*errp = -EPERM;
return -1;
Expand Down
2 changes: 1 addition & 1 deletion net/netlink/genetlink.c
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Original file line number Diff line number Diff line change
Expand Up @@ -320,7 +320,7 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
goto errout;
}

if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb)) {
if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb, CAP_NET_ADMIN)) {
err = -EPERM;
goto errout;
}
Expand Down
2 changes: 1 addition & 1 deletion net/xfrm/xfrm_user.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1435,7 +1435,7 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *err
link = &xfrm_dispatch[type];

/* All operations require privileges, even GET */
if (security_netlink_recv(skb)) {
if (security_netlink_recv(skb, CAP_NET_ADMIN)) {
*errp = -EPERM;
return -1;
}
Expand Down
4 changes: 2 additions & 2 deletions security/commoncap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,9 +33,9 @@ int cap_netlink_send(struct sock *sk, struct sk_buff *skb)

EXPORT_SYMBOL(cap_netlink_send);

int cap_netlink_recv(struct sk_buff *skb)
int cap_netlink_recv(struct sk_buff *skb, int cap)
{
if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN))
if (!cap_raised(NETLINK_CB(skb).eff_cap, cap))
return -EPERM;
return 0;
}
Expand Down
4 changes: 2 additions & 2 deletions security/dummy.c
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Original file line number Diff line number Diff line change
Expand Up @@ -675,9 +675,9 @@ static int dummy_netlink_send (struct sock *sk, struct sk_buff *skb)
return 0;
}

static int dummy_netlink_recv (struct sk_buff *skb)
static int dummy_netlink_recv (struct sk_buff *skb, int cap)
{
if (!cap_raised (NETLINK_CB (skb).eff_cap, CAP_NET_ADMIN))
if (!cap_raised (NETLINK_CB (skb).eff_cap, cap))
return -EPERM;
return 0;
}
Expand Down
26 changes: 13 additions & 13 deletions security/selinux/hooks.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3641,32 +3641,32 @@ static unsigned int selinux_ipv6_postroute_last(unsigned int hooknum,

static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
{
struct task_security_struct *tsec;
struct av_decision avd;
int err;

err = secondary_ops->netlink_send(sk, skb);
if (err)
return err;

tsec = current->security;

avd.allowed = 0;
avc_has_perm_noaudit(tsec->sid, tsec->sid,
SECCLASS_CAPABILITY, ~0, &avd);
cap_mask(NETLINK_CB(skb).eff_cap, avd.allowed);

if (policydb_loaded_version >= POLICYDB_VERSION_NLCLASS)
err = selinux_nlmsg_perm(sk, skb);

return err;
}

static int selinux_netlink_recv(struct sk_buff *skb)
static int selinux_netlink_recv(struct sk_buff *skb, int capability)
{
if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN))
return -EPERM;
return 0;
int err;
struct avc_audit_data ad;

err = secondary_ops->netlink_recv(skb, capability);
if (err)
return err;

AVC_AUDIT_DATA_INIT(&ad, CAP);
ad.u.cap = capability;

return avc_has_perm(NETLINK_CB(skb).sid, NETLINK_CB(skb).sid,
SECCLASS_CAPABILITY, CAP_TO_MASK(capability), &ad);
}

static int ipc_alloc_security(struct task_struct *task,
Expand Down

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