Hi,
with the Linux 2.6.28 kernel the first time xfrm_user.c:xfrm_add_sa()
is called with either "rfc4106(gcm(aes))" or "rfc4309(ccm(aes))",
an EEXIST error is returned and the installation of the IPsec SA fails.
A detailed analysis of the function calls (see trace added below) shows
that aead.c:crypto_lookup_aead() first loads
name : rfc4106(gcm(aes))
driver : rfc4106(gcm_base(ctr(aes-generic)))
module : kernel
priority : 100
refcnt : 1
selftest : passed
type : nivaead
async : yes
blocksize : 1
ivsize : 8
maxauthsize : 16
geniv : seqiv
Because of type=nivaead
if (alg->cra_type == &crypto_aead_type)
return alg;
crypto_lookup_aead() does not return the algorithm and falls through
to the statement
return ERR_PTR(crypto_nivaead_default(alg, type, mask));
which makes another call to algapi.c;__crypto_register_alg().
Because the driver has already been installed
ret = -EEXIST;
...
if (crypto_is_larval(q)) {
if (!strcmp(alg->cra_driver_name, q->cra_driver_name))
goto err;
continue;
}
__crypto_register_alg() exits with the EEXIST error code.
The second time around the type=aead algorithm is additionally loaded
name : rfc4106(gcm(aes))
driver : rfc4106(gcm_base(ctr(aes-generic)))
module : kernel
priority : 100
refcnt : 1
selftest : passed
type : aead
async : yes
blocksize : 1
ivsize : 8
maxauthsize : 16
geniv : seqiv
name : rfc4106(gcm(aes))
driver : rfc4106(gcm_base(ctr(aes-generic)))
module : kernel
priority : 100
refcnt : 1
selftest : passed
type : nivaead
async : yes
blocksize : 1
ivsize : 8
maxauthsize : 16
geniv : seqiv
and the IPsec SAs can be set up successfully.
With the Linux 2.6.27.10 and earlier kernels the aead type is
loaded right at the beginning and no problems occur:
name : rfc4106(gcm(aes))
driver : rfc4106(gcm_base(ctr(aes-asm)))
module : kernel
priority : 200
refcnt : 1
type : aead
async : yes
blocksize : 1
ivsize : 8
maxauthsize : 16
geniv : seqiv
name : rfc4106(gcm(aes))
driver : rfc4106(gcm_base(ctr(aes-asm)))
module : kernel
priority : 200
refcnt : 1
type : nivaead
async : yes
blocksize : 1
ivsize : 8
maxauthsize : 16
geniv : seqiv
Best regards
Andreas
Trace of function calls returning EEXIST:
-----------------------------------------------------------------------------
net/xfrm/xfrm_user.c:xfrm_add_sa()
{
x = xfrm_state_construct(p, attrs, &err);
if (!x)
return err;
}
-----------------------------------------------------------------------------
net/xfrm/xfrm_user.c:xfrm_state_construct()
{
err = xfrm_init_state(x);
if (err)
goto error;
...
error:
x->km.state = XFRM_STATE_DEAD;
xfrm_state_put(x);
error_no_put:
*errp = err;
return NULL;
}
-----------------------------------------------------------------------------
net/xfrm/xfrm_state.c:xfrm_init_state()
{
x->type = xfrm_get_type(x->id.proto, family);
if (x->type == NULL)
goto error;
err = x->type->init_state(x);
if (err)
goto error;
...
error:
return err;
}
-----------------------------------------------------------------------------
linux/net/xfrm.h:struct xfrm_type
{
char *description;
struct module *owner;
__u8 proto;
__u8 flags;
#define XFRM_TYPE_NON_FRAGMENT 1
#define XFRM_TYPE_REPLAY_PROT 2
#define XFRM_TYPE_LOCAL_COADDR 4
#define XFRM_TYPE_REMOTE_COADDR 8
int (*init_state)(struct xfrm_state *x);
void (*destructor)(struct xfrm_state *);
int (*input)(struct xfrm_state *, struct sk_buff *skb);
int (*output)(struct xfrm_state *, struct sk_buff *pskb);
int (*reject)(struct xfrm_state *, struct sk_buff *, struct flowi *);
int (*hdr_offset)(struct xfrm_state *, struct sk_buff *, u8 **);
/* Estimate maximal size of result of transformation of a dgram */
u32 (*get_mtu)(struct xfrm_state *, int size);
};
-----------------------------------------------------------------------------
net/ipv4/esp4.c:esp_init_state()
{
if (x->aead)
err = esp_init_aead(x);
}
else
err = esp_init_authenc(x);
if (err)
goto error;
}
-----------------------------------------------------------------------------
net/ipv4/esp4.c:esp_init_aead()
{
struct esp_data *esp = x->data;
struct crypto_aead *aead;
int err;
aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
err = PTR_ERR(aead);
if (IS_ERR(aead))
goto error;
error:
return err;
}
-----------------------------------------------------------------------------
crypto/aead.c:crypto_alloc_aead()
{
alg = crypto_lookup_aead(alg_name, type, mask);
if (IS_ERR(alg)) {
err = PTR_ERR(alg);
goto err;
}
err:
if (err != -EAGAIN)
break;
if (signal_pending(current)) {
err = -EINTR;
break;
}
}
return ERR_PTR(err);
}
-----------------------------------------------------------------------------
crypto/aead.c:crypto_lookup_aead()
{
struct crypto_alg *alg;
alg = crypto_alg_mod_lookup(name, type, mask);
if (IS_ERR(alg))
return alg;
/* after the first call alg->cra_type is &crypto_nivaead_type */
if (alg->cra_type == &crypto_aead_type)
return alg;
if (!alg->cra_aead.ivsize)
return alg;
return ERR_PTR(crypto_nivaead_default(alg, type, mask));
}
-----------------------------------------------------------------------------
crypto/aead.c:crypto_nivaead_default()
{
if ((err = crypto_register_instance(tmpl, inst))) {
tmpl->free(inst);
goto put_tmpl;
}
/* Redo the lookup to use the instance we just registered. */
err = -EAGAIN;
put_tmpl:
crypto_tmpl_put(tmpl);
kill_larval:
crypto_larval_kill(larval);
drop_larval:
crypto_mod_put(larval);
out:
crypto_mod_put(alg);
return err;
}
-----------------------------------------------------------------------------
crypto/algapi.c:crypto_register_instance()
{
larval = __crypto_register_alg(&inst->alg);
if (IS_ERR(larval))
goto unlock;
hlist_add_head(&inst->list, &tmpl->instances);
inst->tmpl = tmpl;
unlock:
up_write(&crypto_alg_sem);
err = PTR_ERR(larval);
if (IS_ERR(larval))
goto err;
crypto_wait_for_test(larval);
err = 0;
err:
return err;
}
-----------------------------------------------------------------------------
crypto/algapi.c:__crypto_register_alg()
{
ret = -EEXIST;
...
if (crypto_is_larval(q)) {
if (!strcmp(alg->cra_driver_name, q->cra_driver_name))
goto err;
continue;
}
}
Uff!
======================================================================
Andreas Steffen andreas.steffen@xxxxxxxxxxxxxx
strongSwan - the Linux VPN Solution! www.strongswan.org
Institute for Internet Technologies and Applications
University of Applied Sciences Rapperswil
CH-8640 Rapperswil (Switzerland)
===========================================================[ITA-HSR]==
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