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LSM: Make the Labeled IPsec hooks more stack friendly
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The xfrm_get_policy() and xfrm_add_pol_expire() put some rather large structs
on the stack to work around the LSM API.  This patch attempts to fix that
problem by changing the LSM API to require only the relevant "security"
pointers instead of the entire SPD entry; we do this for all of the
security_xfrm_policy*() functions to keep things consistent.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Paul Moore authored and David S. Miller committed Apr 13, 2008
1 parent 0044787 commit 03e1ad7
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Showing 8 changed files with 109 additions and 106 deletions.
48 changes: 24 additions & 24 deletions include/linux/security.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -910,24 +910,24 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
* Security hooks for XFRM operations.
*
* @xfrm_policy_alloc_security:
* @xp contains the xfrm_policy being added to Security Policy Database
* used by the XFRM system.
* @ctxp is a pointer to the xfrm_sec_ctx being added to Security Policy
* Database used by the XFRM system.
* @sec_ctx contains the security context information being provided by
* the user-level policy update program (e.g., setkey).
* Allocate a security structure to the xp->security field; the security
* field is initialized to NULL when the xfrm_policy is allocated.
* Return 0 if operation was successful (memory to allocate, legal context)
* @xfrm_policy_clone_security:
* @old contains an existing xfrm_policy in the SPD.
* @new contains a new xfrm_policy being cloned from old.
* Allocate a security structure to the new->security field
* that contains the information from the old->security field.
* @old_ctx contains an existing xfrm_sec_ctx.
* @new_ctxp contains a new xfrm_sec_ctx being cloned from old.
* Allocate a security structure in new_ctxp that contains the
* information from the old_ctx structure.
* Return 0 if operation was successful (memory to allocate).
* @xfrm_policy_free_security:
* @xp contains the xfrm_policy
* @ctx contains the xfrm_sec_ctx
* Deallocate xp->security.
* @xfrm_policy_delete_security:
* @xp contains the xfrm_policy.
* @ctx contains the xfrm_sec_ctx.
* Authorize deletion of xp->security.
* @xfrm_state_alloc_security:
* @x contains the xfrm_state being added to the Security Association
Expand All @@ -947,7 +947,7 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
* @x contains the xfrm_state.
* Authorize deletion of x->security.
* @xfrm_policy_lookup:
* @xp contains the xfrm_policy for which the access control is being
* @ctx contains the xfrm_sec_ctx for which the access control is being
* checked.
* @fl_secid contains the flow security label that is used to authorize
* access to the policy xp.
Expand Down Expand Up @@ -1454,17 +1454,17 @@ struct security_operations {
#endif /* CONFIG_SECURITY_NETWORK */

#ifdef CONFIG_SECURITY_NETWORK_XFRM
int (*xfrm_policy_alloc_security) (struct xfrm_policy *xp,
int (*xfrm_policy_alloc_security) (struct xfrm_sec_ctx **ctxp,
struct xfrm_user_sec_ctx *sec_ctx);
int (*xfrm_policy_clone_security) (struct xfrm_policy *old, struct xfrm_policy *new);
void (*xfrm_policy_free_security) (struct xfrm_policy *xp);
int (*xfrm_policy_delete_security) (struct xfrm_policy *xp);
int (*xfrm_policy_clone_security) (struct xfrm_sec_ctx *old_ctx, struct xfrm_sec_ctx **new_ctx);
void (*xfrm_policy_free_security) (struct xfrm_sec_ctx *ctx);
int (*xfrm_policy_delete_security) (struct xfrm_sec_ctx *ctx);
int (*xfrm_state_alloc_security) (struct xfrm_state *x,
struct xfrm_user_sec_ctx *sec_ctx,
u32 secid);
void (*xfrm_state_free_security) (struct xfrm_state *x);
int (*xfrm_state_delete_security) (struct xfrm_state *x);
int (*xfrm_policy_lookup)(struct xfrm_policy *xp, u32 fl_secid, u8 dir);
int (*xfrm_policy_lookup)(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir);
int (*xfrm_state_pol_flow_match)(struct xfrm_state *x,
struct xfrm_policy *xp, struct flowi *fl);
int (*xfrm_decode_session)(struct sk_buff *skb, u32 *secid, int ckall);
Expand Down Expand Up @@ -2562,38 +2562,38 @@ static inline void security_inet_conn_established(struct sock *sk,

#ifdef CONFIG_SECURITY_NETWORK_XFRM

int security_xfrm_policy_alloc(struct xfrm_policy *xp, struct xfrm_user_sec_ctx *sec_ctx);
int security_xfrm_policy_clone(struct xfrm_policy *old, struct xfrm_policy *new);
void security_xfrm_policy_free(struct xfrm_policy *xp);
int security_xfrm_policy_delete(struct xfrm_policy *xp);
int security_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp, struct xfrm_user_sec_ctx *sec_ctx);
int security_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx, struct xfrm_sec_ctx **new_ctxp);
void security_xfrm_policy_free(struct xfrm_sec_ctx *ctx);
int security_xfrm_policy_delete(struct xfrm_sec_ctx *ctx);
int security_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *sec_ctx);
int security_xfrm_state_alloc_acquire(struct xfrm_state *x,
struct xfrm_sec_ctx *polsec, u32 secid);
int security_xfrm_state_delete(struct xfrm_state *x);
void security_xfrm_state_free(struct xfrm_state *x);
int security_xfrm_policy_lookup(struct xfrm_policy *xp, u32 fl_secid, u8 dir);
int security_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir);
int security_xfrm_state_pol_flow_match(struct xfrm_state *x,
struct xfrm_policy *xp, struct flowi *fl);
int security_xfrm_decode_session(struct sk_buff *skb, u32 *secid);
void security_skb_classify_flow(struct sk_buff *skb, struct flowi *fl);

#else /* CONFIG_SECURITY_NETWORK_XFRM */

static inline int security_xfrm_policy_alloc(struct xfrm_policy *xp, struct xfrm_user_sec_ctx *sec_ctx)
static inline int security_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp, struct xfrm_user_sec_ctx *sec_ctx)
{
return 0;
}

static inline int security_xfrm_policy_clone(struct xfrm_policy *old, struct xfrm_policy *new)
static inline int security_xfrm_policy_clone(struct xfrm_sec_ctx *old, struct xfrm_sec_ctx **new_ctxp)
{
return 0;
}

static inline void security_xfrm_policy_free(struct xfrm_policy *xp)
static inline void security_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
{
}

static inline int security_xfrm_policy_delete(struct xfrm_policy *xp)
static inline int security_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
{
return 0;
}
Expand All @@ -2619,7 +2619,7 @@ static inline int security_xfrm_state_delete(struct xfrm_state *x)
return 0;
}

static inline int security_xfrm_policy_lookup(struct xfrm_policy *xp, u32 fl_secid, u8 dir)
static inline int security_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir)
{
return 0;
}
Expand Down
23 changes: 11 additions & 12 deletions net/key/af_key.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2292,7 +2292,7 @@ static int pfkey_spdadd(struct sock *sk, struct sk_buff *skb, struct sadb_msg *h
goto out;
}

err = security_xfrm_policy_alloc(xp, uctx);
err = security_xfrm_policy_alloc(&xp->security, uctx);
kfree(uctx);

if (err)
Expand Down Expand Up @@ -2352,10 +2352,11 @@ static int pfkey_spddelete(struct sock *sk, struct sk_buff *skb, struct sadb_msg
int err;
struct sadb_address *sa;
struct sadb_x_policy *pol;
struct xfrm_policy *xp, tmp;
struct xfrm_policy *xp;
struct xfrm_selector sel;
struct km_event c;
struct sadb_x_sec_ctx *sec_ctx;
struct xfrm_sec_ctx *pol_ctx;

if (!present_and_same_family(ext_hdrs[SADB_EXT_ADDRESS_SRC-1],
ext_hdrs[SADB_EXT_ADDRESS_DST-1]) ||
Expand Down Expand Up @@ -2385,25 +2386,23 @@ static int pfkey_spddelete(struct sock *sk, struct sk_buff *skb, struct sadb_msg
sel.dport_mask = htons(0xffff);

sec_ctx = (struct sadb_x_sec_ctx *) ext_hdrs[SADB_X_EXT_SEC_CTX-1];
memset(&tmp, 0, sizeof(struct xfrm_policy));

if (sec_ctx != NULL) {
struct xfrm_user_sec_ctx *uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx);

if (!uctx)
return -ENOMEM;

err = security_xfrm_policy_alloc(&tmp, uctx);
err = security_xfrm_policy_alloc(&pol_ctx, uctx);
kfree(uctx);

if (err)
return err;
}

xp = xfrm_policy_bysel_ctx(XFRM_POLICY_TYPE_MAIN, pol->sadb_x_policy_dir-1,
&sel, tmp.security, 1, &err);
security_xfrm_policy_free(&tmp);
} else
pol_ctx = NULL;

xp = xfrm_policy_bysel_ctx(XFRM_POLICY_TYPE_MAIN,
pol->sadb_x_policy_dir - 1, &sel, pol_ctx,
1, &err);
security_xfrm_policy_free(pol_ctx);
if (xp == NULL)
return -ENOENT;

Expand Down Expand Up @@ -3298,7 +3297,7 @@ static struct xfrm_policy *pfkey_compile_policy(struct sock *sk, int opt,
if ((*dir = verify_sec_ctx_len(p)))
goto out;
uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx);
*dir = security_xfrm_policy_alloc(xp, uctx);
*dir = security_xfrm_policy_alloc(&xp->security, uctx);
kfree(uctx);

if (*dir)
Expand Down
24 changes: 15 additions & 9 deletions net/xfrm/xfrm_policy.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -263,7 +263,7 @@ void xfrm_policy_destroy(struct xfrm_policy *policy)
list_del(&policy->bytype);
write_unlock_bh(&xfrm_policy_lock);

security_xfrm_policy_free(policy);
security_xfrm_policy_free(policy->security);
kfree(policy);
}
EXPORT_SYMBOL(xfrm_policy_destroy);
Expand Down Expand Up @@ -676,7 +676,8 @@ struct xfrm_policy *xfrm_policy_bysel_ctx(u8 type, int dir,
xfrm_sec_ctx_match(ctx, pol->security)) {
xfrm_pol_hold(pol);
if (delete) {
*err = security_xfrm_policy_delete(pol);
*err = security_xfrm_policy_delete(
pol->security);
if (*err) {
write_unlock_bh(&xfrm_policy_lock);
return pol;
Expand Down Expand Up @@ -718,7 +719,8 @@ struct xfrm_policy *xfrm_policy_byid(u8 type, int dir, u32 id, int delete,
if (pol->type == type && pol->index == id) {
xfrm_pol_hold(pol);
if (delete) {
*err = security_xfrm_policy_delete(pol);
*err = security_xfrm_policy_delete(
pol->security);
if (*err) {
write_unlock_bh(&xfrm_policy_lock);
return pol;
Expand Down Expand Up @@ -756,7 +758,7 @@ xfrm_policy_flush_secctx_check(u8 type, struct xfrm_audit *audit_info)
&xfrm_policy_inexact[dir], bydst) {
if (pol->type != type)
continue;
err = security_xfrm_policy_delete(pol);
err = security_xfrm_policy_delete(pol->security);
if (err) {
xfrm_audit_policy_delete(pol, 0,
audit_info->loginuid,
Expand All @@ -770,7 +772,8 @@ xfrm_policy_flush_secctx_check(u8 type, struct xfrm_audit *audit_info)
bydst) {
if (pol->type != type)
continue;
err = security_xfrm_policy_delete(pol);
err = security_xfrm_policy_delete(
pol->security);
if (err) {
xfrm_audit_policy_delete(pol, 0,
audit_info->loginuid,
Expand Down Expand Up @@ -931,7 +934,8 @@ static int xfrm_policy_match(struct xfrm_policy *pol, struct flowi *fl,

match = xfrm_selector_match(sel, fl, family);
if (match)
ret = security_xfrm_policy_lookup(pol, fl->secid, dir);
ret = security_xfrm_policy_lookup(pol->security, fl->secid,
dir);

return ret;
}
Expand Down Expand Up @@ -1048,8 +1052,9 @@ static struct xfrm_policy *xfrm_sk_policy_lookup(struct sock *sk, int dir, struc
int err = 0;

if (match) {
err = security_xfrm_policy_lookup(pol, fl->secid,
policy_to_flow_dir(dir));
err = security_xfrm_policy_lookup(pol->security,
fl->secid,
policy_to_flow_dir(dir));
if (!err)
xfrm_pol_hold(pol);
else if (err == -ESRCH)
Expand Down Expand Up @@ -1138,7 +1143,8 @@ static struct xfrm_policy *clone_policy(struct xfrm_policy *old, int dir)

if (newp) {
newp->selector = old->selector;
if (security_xfrm_policy_clone(old, newp)) {
if (security_xfrm_policy_clone(old->security,
&newp->security)) {
kfree(newp);
return NULL; /* ENOMEM */
}
Expand Down
33 changes: 17 additions & 16 deletions net/xfrm/xfrm_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -959,7 +959,7 @@ static int copy_from_user_sec_ctx(struct xfrm_policy *pol, struct nlattr **attrs
return 0;

uctx = nla_data(rt);
return security_xfrm_policy_alloc(pol, uctx);
return security_xfrm_policy_alloc(&pol->security, uctx);
}

static void copy_templates(struct xfrm_policy *xp, struct xfrm_user_tmpl *ut,
Expand Down Expand Up @@ -1143,7 +1143,7 @@ static int xfrm_add_policy(struct sk_buff *skb, struct nlmsghdr *nlh,
NETLINK_CB(skb).sid);

if (err) {
security_xfrm_policy_free(xp);
security_xfrm_policy_free(xp->security);
kfree(xp);
return err;
}
Expand Down Expand Up @@ -1337,22 +1337,23 @@ static int xfrm_get_policy(struct sk_buff *skb, struct nlmsghdr *nlh,
xp = xfrm_policy_byid(type, p->dir, p->index, delete, &err);
else {
struct nlattr *rt = attrs[XFRMA_SEC_CTX];
struct xfrm_policy tmp;
struct xfrm_sec_ctx *ctx;

err = verify_sec_ctx_len(attrs);
if (err)
return err;

memset(&tmp, 0, sizeof(struct xfrm_policy));
if (rt) {
struct xfrm_user_sec_ctx *uctx = nla_data(rt);

if ((err = security_xfrm_policy_alloc(&tmp, uctx)))
err = security_xfrm_policy_alloc(&ctx, uctx);
if (err)
return err;
}
xp = xfrm_policy_bysel_ctx(type, p->dir, &p->sel, tmp.security,
} else
ctx = NULL;
xp = xfrm_policy_bysel_ctx(type, p->dir, &p->sel, ctx,
delete, &err);
security_xfrm_policy_free(&tmp);
security_xfrm_policy_free(ctx);
}
if (xp == NULL)
return -ENOENT;
Expand Down Expand Up @@ -1572,26 +1573,26 @@ static int xfrm_add_pol_expire(struct sk_buff *skb, struct nlmsghdr *nlh,
xp = xfrm_policy_byid(type, p->dir, p->index, 0, &err);
else {
struct nlattr *rt = attrs[XFRMA_SEC_CTX];
struct xfrm_policy tmp;
struct xfrm_sec_ctx *ctx;

err = verify_sec_ctx_len(attrs);
if (err)
return err;

memset(&tmp, 0, sizeof(struct xfrm_policy));
if (rt) {
struct xfrm_user_sec_ctx *uctx = nla_data(rt);

if ((err = security_xfrm_policy_alloc(&tmp, uctx)))
err = security_xfrm_policy_alloc(&ctx, uctx);
if (err)
return err;
}
xp = xfrm_policy_bysel_ctx(type, p->dir, &p->sel, tmp.security,
0, &err);
security_xfrm_policy_free(&tmp);
} else
ctx = NULL;
xp = xfrm_policy_bysel_ctx(type, p->dir, &p->sel, ctx, 0, &err);
security_xfrm_policy_free(ctx);
}

if (xp == NULL)
return -ENOENT;

read_lock(&xp->lock);
if (xp->dead) {
read_unlock(&xp->lock);
Expand Down
14 changes: 8 additions & 6 deletions security/dummy.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -876,22 +876,23 @@ static inline void dummy_req_classify_flow(const struct request_sock *req,
#endif /* CONFIG_SECURITY_NETWORK */

#ifdef CONFIG_SECURITY_NETWORK_XFRM
static int dummy_xfrm_policy_alloc_security(struct xfrm_policy *xp,
struct xfrm_user_sec_ctx *sec_ctx)
static int dummy_xfrm_policy_alloc_security(struct xfrm_sec_ctx **ctxp,
struct xfrm_user_sec_ctx *sec_ctx)
{
return 0;
}

static inline int dummy_xfrm_policy_clone_security(struct xfrm_policy *old, struct xfrm_policy *new)
static inline int dummy_xfrm_policy_clone_security(struct xfrm_sec_ctx *old_ctx,
struct xfrm_sec_ctx **new_ctxp)
{
return 0;
}

static void dummy_xfrm_policy_free_security(struct xfrm_policy *xp)
static void dummy_xfrm_policy_free_security(struct xfrm_sec_ctx *ctx)
{
}

static int dummy_xfrm_policy_delete_security(struct xfrm_policy *xp)
static int dummy_xfrm_policy_delete_security(struct xfrm_sec_ctx *ctx)
{
return 0;
}
Expand All @@ -911,7 +912,8 @@ static int dummy_xfrm_state_delete_security(struct xfrm_state *x)
return 0;
}

static int dummy_xfrm_policy_lookup(struct xfrm_policy *xp, u32 sk_sid, u8 dir)
static int dummy_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx,
u32 sk_sid, u8 dir)
{
return 0;
}
Expand Down
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