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Subject[PATCH v3 5/7] xfrm/compat: Add 32=>64-bit messages translator
Date
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>
---
include/net/xfrm.h | 6 +
net/xfrm/Kconfig | 3 +-
net/xfrm/xfrm_compat.c | 274 +++++++++++++++++++++++++++++++++++++++++
net/xfrm/xfrm_user.c | 57 ++++++---
4 files changed, 321 insertions(+), 19 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 5b6cc62c9354..fa18cb6bb3f7 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -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;
};

diff --git a/net/xfrm/Kconfig b/net/xfrm/Kconfig
index e79b48dab61b..3adf31a83a79 100644
--- a/net/xfrm/Kconfig
+++ b/net/xfrm/Kconfig
@@ -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
diff --git a/net/xfrm/xfrm_compat.c b/net/xfrm/xfrm_compat.c
index aece41b44ff2..b1b5f972538d 100644
--- a/net/xfrm/xfrm_compat.c
+++ b/net/xfrm/xfrm_compat.c
@@ -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)
{
@@ -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)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 7fd7b16a8805..d0c32a8fcc4a 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1019,7 +1019,6 @@ static int xfrm_dump_sa_done(struct netlink_callback *cb)
return 0;
}

-static const struct nla_policy xfrma_policy[XFRMA_MAX+1];
static int xfrm_dump_sa(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
@@ -2610,7 +2609,7 @@ EXPORT_SYMBOL_GPL(xfrm_msg_min);

#undef XMSGSIZE

-static const struct nla_policy xfrma_policy[XFRMA_MAX+1] = {
+const struct nla_policy xfrma_policy[XFRMA_MAX+1] = {
[XFRMA_SA] = { .len = sizeof(struct xfrm_usersa_info)},
[XFRMA_POLICY] = { .len = sizeof(struct xfrm_userpolicy_info)},
[XFRMA_LASTUSED] = { .type = NLA_U64},
@@ -2642,6 +2641,7 @@ static const struct nla_policy xfrma_policy[XFRMA_MAX+1] = {
[XFRMA_SET_MARK_MASK] = { .type = NLA_U32 },
[XFRMA_IF_ID] = { .type = NLA_U32 },
};
+EXPORT_SYMBOL_GPL(xfrma_policy);

static const struct nla_policy xfrma_spd_policy[XFRMA_SPD_MAX+1] = {
[XFRMA_SPD_IPV4_HTHRESH] = { .len = sizeof(struct xfrmu_spdhthresh) },
@@ -2691,11 +2691,9 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
struct net *net = sock_net(skb->sk);
struct nlattr *attrs[XFRMA_MAX+1];
const struct xfrm_link *link;
+ struct nlmsghdr *nlh64 = NULL;
int type, err;

- if (in_compat_syscall())
- return -EOPNOTSUPP;
-
type = nlh->nlmsg_type;
if (type > XFRM_MSG_MAX)
return -EINVAL;
@@ -2707,32 +2705,55 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
if (!netlink_net_capable(skb, CAP_NET_ADMIN))
return -EPERM;

+ if (in_compat_syscall()) {
+ struct xfrm_translator *xtr = xfrm_get_translator();
+
+ if (!xtr)
+ return -EOPNOTSUPP;
+
+ nlh64 = xtr->rcv_msg_compat(nlh, link->nla_max,
+ link->nla_pol, extack);
+ xfrm_put_translator(xtr);
+ if (IS_ERR(nlh64))
+ return PTR_ERR(nlh64);
+ if (nlh64)
+ nlh = nlh64;
+ }
+
if ((type == (XFRM_MSG_GETSA - XFRM_MSG_BASE) ||
type == (XFRM_MSG_GETPOLICY - XFRM_MSG_BASE)) &&
(nlh->nlmsg_flags & NLM_F_DUMP)) {
- if (link->dump == NULL)
- return -EINVAL;
+ struct netlink_dump_control c = {
+ .start = link->start,
+ .dump = link->dump,
+ .done = link->done,
+ };

- {
- struct netlink_dump_control c = {
- .start = link->start,
- .dump = link->dump,
- .done = link->done,
- };
- return netlink_dump_start(net->xfrm.nlsk, skb, nlh, &c);
+ if (link->dump == NULL) {
+ err = -EINVAL;
+ goto err;
}
+
+ err = netlink_dump_start(net->xfrm.nlsk, skb, nlh, &c);
+ goto err;
}

err = nlmsg_parse_deprecated(nlh, xfrm_msg_min[type], attrs,
link->nla_max ? : XFRMA_MAX,
link->nla_pol ? : xfrma_policy, extack);
if (err < 0)
- return err;
+ goto err;

- if (link->doit == NULL)
- return -EINVAL;
+ if (link->doit == NULL) {
+ err = -EINVAL;
+ goto err;
+ }
+
+ err = link->doit(skb, nlh, attrs);

- return link->doit(skb, nlh, attrs);
+err:
+ kvfree(nlh64);
+ return err;
}

static void xfrm_netlink_rcv(struct sk_buff *skb)
--
2.28.0
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