Skip to content

Commit

Permalink
xfrm/compat: Add 32=>64-bit messages translator
Browse files Browse the repository at this point in the history 
Provide the user-to-kernel translator under XFRM_USER_COMPAT, that
creates for 32-bit xfrm-user message a 64-bit translation.
The translation is afterwards reused by xfrm_user code just as if
userspace had sent 64-bit message.

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
  • Loading branch information
Dmitry Safonov authored and Steffen Klassert committed Sep 24, 2020
1 parent e11eb32 commit 5106f4a
Show file tree
Hide file tree
Showing 4 changed files with 321 additions and 19 deletions.
6 changes: 6 additions & 0 deletions include/net/xfrm.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2001,11 +2001,17 @@ static inline int xfrm_tunnel_check(struct sk_buff *skb, struct xfrm_state *x,
}

extern const int xfrm_msg_min[XFRM_NR_MSGTYPES];
extern const struct nla_policy xfrma_policy[XFRMA_MAX+1];

struct xfrm_translator {
/* Allocate frag_list and put compat translation there */
int (*alloc_compat)(struct sk_buff *skb, const struct nlmsghdr *src);

/* Allocate nlmsg with 64-bit translaton of received 32-bit message */
struct nlmsghdr *(*rcv_msg_compat)(const struct nlmsghdr *nlh,
int maxtype, const struct nla_policy *policy,
struct netlink_ext_ack *extack);

struct module *owner;
};

Expand Down
3 changes: 2 additions & 1 deletion net/xfrm/Kconfig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,8 @@ config XFRM_USER

config XFRM_USER_COMPAT
tristate "Compatible ABI support"
depends on XFRM_USER && COMPAT_FOR_U64_ALIGNMENT
depends on XFRM_USER && COMPAT_FOR_U64_ALIGNMENT && \
HAVE_EFFICIENT_UNALIGNED_ACCESS
select WANT_COMPAT_NETLINK_MESSAGES
help
Transformation(XFRM) user configuration interface like IPsec
Expand Down
274 changes: 274 additions & 0 deletions net/xfrm/xfrm_compat.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -96,6 +96,39 @@ static const int compat_msg_min[XFRM_NR_MSGTYPES] = {
[XFRM_MSG_MAPPING - XFRM_MSG_BASE] = XMSGSIZE(xfrm_user_mapping)
};

static const struct nla_policy compat_policy[XFRMA_MAX+1] = {
[XFRMA_SA] = { .len = XMSGSIZE(compat_xfrm_usersa_info)},
[XFRMA_POLICY] = { .len = XMSGSIZE(compat_xfrm_userpolicy_info)},
[XFRMA_LASTUSED] = { .type = NLA_U64},
[XFRMA_ALG_AUTH_TRUNC] = { .len = sizeof(struct xfrm_algo_auth)},
[XFRMA_ALG_AEAD] = { .len = sizeof(struct xfrm_algo_aead) },
[XFRMA_ALG_AUTH] = { .len = sizeof(struct xfrm_algo) },
[XFRMA_ALG_CRYPT] = { .len = sizeof(struct xfrm_algo) },
[XFRMA_ALG_COMP] = { .len = sizeof(struct xfrm_algo) },
[XFRMA_ENCAP] = { .len = sizeof(struct xfrm_encap_tmpl) },
[XFRMA_TMPL] = { .len = sizeof(struct xfrm_user_tmpl) },
[XFRMA_SEC_CTX] = { .len = sizeof(struct xfrm_sec_ctx) },
[XFRMA_LTIME_VAL] = { .len = sizeof(struct xfrm_lifetime_cur) },
[XFRMA_REPLAY_VAL] = { .len = sizeof(struct xfrm_replay_state) },
[XFRMA_REPLAY_THRESH] = { .type = NLA_U32 },
[XFRMA_ETIMER_THRESH] = { .type = NLA_U32 },
[XFRMA_SRCADDR] = { .len = sizeof(xfrm_address_t) },
[XFRMA_COADDR] = { .len = sizeof(xfrm_address_t) },
[XFRMA_POLICY_TYPE] = { .len = sizeof(struct xfrm_userpolicy_type)},
[XFRMA_MIGRATE] = { .len = sizeof(struct xfrm_user_migrate) },
[XFRMA_KMADDRESS] = { .len = sizeof(struct xfrm_user_kmaddress) },
[XFRMA_MARK] = { .len = sizeof(struct xfrm_mark) },
[XFRMA_TFCPAD] = { .type = NLA_U32 },
[XFRMA_REPLAY_ESN_VAL] = { .len = sizeof(struct xfrm_replay_state_esn) },
[XFRMA_SA_EXTRA_FLAGS] = { .type = NLA_U32 },
[XFRMA_PROTO] = { .type = NLA_U8 },
[XFRMA_ADDRESS_FILTER] = { .len = sizeof(struct xfrm_address_filter) },
[XFRMA_OFFLOAD_DEV] = { .len = sizeof(struct xfrm_user_offload) },
[XFRMA_SET_MARK] = { .type = NLA_U32 },
[XFRMA_SET_MARK_MASK] = { .type = NLA_U32 },
[XFRMA_IF_ID] = { .type = NLA_U32 },
};

static struct nlmsghdr *xfrm_nlmsg_put_compat(struct sk_buff *skb,
const struct nlmsghdr *nlh_src, u16 type)
{
Expand Down Expand Up @@ -303,9 +336,250 @@ static int xfrm_alloc_compat(struct sk_buff *skb, const struct nlmsghdr *nlh_src
return 0;
}

/* Calculates len of translated 64-bit message. */
static size_t xfrm_user_rcv_calculate_len64(const struct nlmsghdr *src,
struct nlattr *attrs[XFRMA_MAX+1])
{
size_t len = nlmsg_len(src);

switch (src->nlmsg_type) {
case XFRM_MSG_NEWSA:
case XFRM_MSG_NEWPOLICY:
case XFRM_MSG_ALLOCSPI:
case XFRM_MSG_ACQUIRE:
case XFRM_MSG_UPDPOLICY:
case XFRM_MSG_UPDSA:
len += 4;
break;
case XFRM_MSG_EXPIRE:
case XFRM_MSG_POLEXPIRE:
len += 8;
break;
default:
break;
}

if (attrs[XFRMA_SA])
len += 4;
if (attrs[XFRMA_POLICY])
len += 4;

/* XXX: some attrs may need to be realigned
* if !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
*/

return len;
}

static int xfrm_attr_cpy32(void *dst, size_t *pos, const struct nlattr *src,
size_t size, int copy_len, int payload)
{
struct nlmsghdr *nlmsg = dst;
struct nlattr *nla;

if (WARN_ON_ONCE(copy_len > payload))
copy_len = payload;

if (size - *pos < nla_attr_size(payload))
return -ENOBUFS;

nla = dst + *pos;

memcpy(nla, src, nla_attr_size(copy_len));
nla->nla_len = nla_attr_size(payload);
*pos += nla_attr_size(payload);
nlmsg->nlmsg_len += nla->nla_len;

memset(dst + *pos, 0, payload - copy_len);
*pos += payload - copy_len;

return 0;
}

static int xfrm_xlate32_attr(void *dst, const struct nlattr *nla,
size_t *pos, size_t size,
struct netlink_ext_ack *extack)
{
int type = nla_type(nla);
u16 pol_len32, pol_len64;
int err;

if (type > XFRMA_MAX) {
BUILD_BUG_ON(XFRMA_MAX != XFRMA_IF_ID);
NL_SET_ERR_MSG(extack, "Bad attribute");
return -EOPNOTSUPP;
}
if (nla_len(nla) < compat_policy[type].len) {
NL_SET_ERR_MSG(extack, "Attribute bad length");
return -EOPNOTSUPP;
}

pol_len32 = compat_policy[type].len;
pol_len64 = xfrma_policy[type].len;

/* XFRMA_SA and XFRMA_POLICY - need to know how-to translate */
if (pol_len32 != pol_len64) {
if (nla_len(nla) != compat_policy[type].len) {
NL_SET_ERR_MSG(extack, "Attribute bad length");
return -EOPNOTSUPP;
}
err = xfrm_attr_cpy32(dst, pos, nla, size, pol_len32, pol_len64);
if (err)
return err;
}

return xfrm_attr_cpy32(dst, pos, nla, size, nla_len(nla), nla_len(nla));
}

static int xfrm_xlate32(struct nlmsghdr *dst, const struct nlmsghdr *src,
struct nlattr *attrs[XFRMA_MAX+1],
size_t size, u8 type, struct netlink_ext_ack *extack)
{
size_t pos;
int i;

memcpy(dst, src, NLMSG_HDRLEN);
dst->nlmsg_len = NLMSG_HDRLEN + xfrm_msg_min[type];
memset(nlmsg_data(dst), 0, xfrm_msg_min[type]);

switch (src->nlmsg_type) {
/* Compat message has the same layout as native */
case XFRM_MSG_DELSA:
case XFRM_MSG_GETSA:
case XFRM_MSG_DELPOLICY:
case XFRM_MSG_GETPOLICY:
case XFRM_MSG_FLUSHSA:
case XFRM_MSG_FLUSHPOLICY:
case XFRM_MSG_NEWAE:
case XFRM_MSG_GETAE:
case XFRM_MSG_REPORT:
case XFRM_MSG_MIGRATE:
case XFRM_MSG_NEWSADINFO:
case XFRM_MSG_GETSADINFO:
case XFRM_MSG_NEWSPDINFO:
case XFRM_MSG_GETSPDINFO:
case XFRM_MSG_MAPPING:
memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
break;
/* 4 byte alignment for trailing u64 on native, but not on compat */
case XFRM_MSG_NEWSA:
case XFRM_MSG_NEWPOLICY:
case XFRM_MSG_UPDSA:
case XFRM_MSG_UPDPOLICY:
memcpy(nlmsg_data(dst), nlmsg_data(src), compat_msg_min[type]);
break;
case XFRM_MSG_EXPIRE: {
const struct compat_xfrm_user_expire *src_ue = nlmsg_data(src);
struct xfrm_user_expire *dst_ue = nlmsg_data(dst);

/* compat_xfrm_user_expire has 4-byte smaller state */
memcpy(dst_ue, src_ue, sizeof(src_ue->state));
dst_ue->hard = src_ue->hard;
break;
}
case XFRM_MSG_ACQUIRE: {
const struct compat_xfrm_user_acquire *src_ua = nlmsg_data(src);
struct xfrm_user_acquire *dst_ua = nlmsg_data(dst);

memcpy(dst_ua, src_ua, offsetof(struct compat_xfrm_user_acquire, aalgos));
dst_ua->aalgos = src_ua->aalgos;
dst_ua->ealgos = src_ua->ealgos;
dst_ua->calgos = src_ua->calgos;
dst_ua->seq = src_ua->seq;
break;
}
case XFRM_MSG_POLEXPIRE: {
const struct compat_xfrm_user_polexpire *src_upe = nlmsg_data(src);
struct xfrm_user_polexpire *dst_upe = nlmsg_data(dst);

/* compat_xfrm_user_polexpire has 4-byte smaller state */
memcpy(dst_upe, src_upe, sizeof(src_upe->pol));
dst_upe->hard = src_upe->hard;
break;
}
case XFRM_MSG_ALLOCSPI: {
const struct compat_xfrm_userspi_info *src_usi = nlmsg_data(src);
struct xfrm_userspi_info *dst_usi = nlmsg_data(dst);

/* compat_xfrm_user_polexpire has 4-byte smaller state */
memcpy(dst_usi, src_usi, sizeof(src_usi->info));
dst_usi->min = src_usi->min;
dst_usi->max = src_usi->max;
break;
}
default:
NL_SET_ERR_MSG(extack, "Unsupported message type");
return -EOPNOTSUPP;
}
pos = dst->nlmsg_len;

for (i = 1; i < XFRMA_MAX + 1; i++) {
int err;

if (i == XFRMA_PAD)
continue;

if (!attrs[i])
continue;

err = xfrm_xlate32_attr(dst, attrs[i], &pos, size, extack);
if (err)
return err;
}

return 0;
}

static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32,
int maxtype, const struct nla_policy *policy,
struct netlink_ext_ack *extack)
{
/* netlink_rcv_skb() checks if a message has full (struct nlmsghdr) */
u16 type = h32->nlmsg_type - XFRM_MSG_BASE;
struct nlattr *attrs[XFRMA_MAX+1];
struct nlmsghdr *h64;
size_t len;
int err;

BUILD_BUG_ON(ARRAY_SIZE(xfrm_msg_min) != ARRAY_SIZE(compat_msg_min));

if (type >= ARRAY_SIZE(xfrm_msg_min))
return ERR_PTR(-EINVAL);

/* Don't call parse: the message might have only nlmsg header */
if ((h32->nlmsg_type == XFRM_MSG_GETSA ||
h32->nlmsg_type == XFRM_MSG_GETPOLICY) &&
(h32->nlmsg_flags & NLM_F_DUMP))
return NULL;

err = nlmsg_parse_deprecated(h32, compat_msg_min[type], attrs,
maxtype ? : XFRMA_MAX, policy ? : compat_policy, extack);
if (err < 0)
return ERR_PTR(err);

len = xfrm_user_rcv_calculate_len64(h32, attrs);
/* The message doesn't need translation */
if (len == nlmsg_len(h32))
return NULL;

len += NLMSG_HDRLEN;
h64 = kvmalloc(len, GFP_KERNEL | __GFP_ZERO);
if (!h64)
return ERR_PTR(-ENOMEM);

err = xfrm_xlate32(h64, h32, attrs, len, type, extack);
if (err < 0) {
kvfree(h64);
return ERR_PTR(err);
}

return h64;
}

static struct xfrm_translator xfrm_translator = {
.owner = THIS_MODULE,
.alloc_compat = xfrm_alloc_compat,
.rcv_msg_compat = xfrm_user_rcv_msg_compat,
};

static int __init xfrm_compat_init(void)
Expand Down
Loading

0 comments on commit 5106f4a

Please sign in to comment.