xfrm/compat: Add 64=>32-bit messages translator

Provide the kernel-to-user translator under XFRM_USER_COMPAT, that
creates for 64-bit xfrm-user message a 32-bit translation and puts it
in skb's frag_list. net/compat.c layer provides MSG_CMSG_COMPAT to
decide if the message should be taken from skb or frag_list.
(used by wext-core which has also an ABI difference)

Kernel sends 64-bit xfrm messages to the userspace for:
- multicast (monitor events)
- netlink dumps

Wire up the translator to xfrm_nlmsg_multicast().

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Dmitry Safonov 2020-09-21 15:36:52 +01:00 committed by Steffen Klassert
parent c9e7c76d70
commit 5461fc0c8d
3 changed files with 315 additions and 1 deletions

View File

@ -2000,7 +2000,12 @@ static inline int xfrm_tunnel_check(struct sk_buff *skb, struct xfrm_state *x,
return 0;
}
extern const int xfrm_msg_min[XFRM_NR_MSGTYPES];
struct xfrm_translator {
/* Allocate frag_list and put compat translation there */
int (*alloc_compat)(struct sk_buff *skb, const struct nlmsghdr *src);
struct module *owner;
};

View File

@ -8,8 +8,304 @@
#include <linux/xfrm.h>
#include <net/xfrm.h>
struct compat_xfrm_lifetime_cfg {
compat_u64 soft_byte_limit, hard_byte_limit;
compat_u64 soft_packet_limit, hard_packet_limit;
compat_u64 soft_add_expires_seconds, hard_add_expires_seconds;
compat_u64 soft_use_expires_seconds, hard_use_expires_seconds;
}; /* same size on 32bit, but only 4 byte alignment required */
struct compat_xfrm_lifetime_cur {
compat_u64 bytes, packets, add_time, use_time;
}; /* same size on 32bit, but only 4 byte alignment required */
struct compat_xfrm_userpolicy_info {
struct xfrm_selector sel;
struct compat_xfrm_lifetime_cfg lft;
struct compat_xfrm_lifetime_cur curlft;
__u32 priority, index;
u8 dir, action, flags, share;
/* 4 bytes additional padding on 64bit */
};
struct compat_xfrm_usersa_info {
struct xfrm_selector sel;
struct xfrm_id id;
xfrm_address_t saddr;
struct compat_xfrm_lifetime_cfg lft;
struct compat_xfrm_lifetime_cur curlft;
struct xfrm_stats stats;
__u32 seq, reqid;
u16 family;
u8 mode, replay_window, flags;
/* 4 bytes additional padding on 64bit */
};
struct compat_xfrm_user_acquire {
struct xfrm_id id;
xfrm_address_t saddr;
struct xfrm_selector sel;
struct compat_xfrm_userpolicy_info policy;
/* 4 bytes additional padding on 64bit */
__u32 aalgos, ealgos, calgos, seq;
};
struct compat_xfrm_userspi_info {
struct compat_xfrm_usersa_info info;
/* 4 bytes additional padding on 64bit */
__u32 min, max;
};
struct compat_xfrm_user_expire {
struct compat_xfrm_usersa_info state;
/* 8 bytes additional padding on 64bit */
u8 hard;
};
struct compat_xfrm_user_polexpire {
struct compat_xfrm_userpolicy_info pol;
/* 8 bytes additional padding on 64bit */
u8 hard;
};
#define XMSGSIZE(type) sizeof(struct type)
static const int compat_msg_min[XFRM_NR_MSGTYPES] = {
[XFRM_MSG_NEWSA - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_usersa_info),
[XFRM_MSG_DELSA - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_id),
[XFRM_MSG_GETSA - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_id),
[XFRM_MSG_NEWPOLICY - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_userpolicy_info),
[XFRM_MSG_DELPOLICY - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_id),
[XFRM_MSG_GETPOLICY - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_id),
[XFRM_MSG_ALLOCSPI - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_userspi_info),
[XFRM_MSG_ACQUIRE - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_user_acquire),
[XFRM_MSG_EXPIRE - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_user_expire),
[XFRM_MSG_UPDPOLICY - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_userpolicy_info),
[XFRM_MSG_UPDSA - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_usersa_info),
[XFRM_MSG_POLEXPIRE - XFRM_MSG_BASE] = XMSGSIZE(compat_xfrm_user_polexpire),
[XFRM_MSG_FLUSHSA - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_flush),
[XFRM_MSG_FLUSHPOLICY - XFRM_MSG_BASE] = 0,
[XFRM_MSG_NEWAE - XFRM_MSG_BASE] = XMSGSIZE(xfrm_aevent_id),
[XFRM_MSG_GETAE - XFRM_MSG_BASE] = XMSGSIZE(xfrm_aevent_id),
[XFRM_MSG_REPORT - XFRM_MSG_BASE] = XMSGSIZE(xfrm_user_report),
[XFRM_MSG_MIGRATE - XFRM_MSG_BASE] = XMSGSIZE(xfrm_userpolicy_id),
[XFRM_MSG_NEWSADINFO - XFRM_MSG_BASE] = sizeof(u32),
[XFRM_MSG_GETSADINFO - XFRM_MSG_BASE] = sizeof(u32),
[XFRM_MSG_NEWSPDINFO - XFRM_MSG_BASE] = sizeof(u32),
[XFRM_MSG_GETSPDINFO - XFRM_MSG_BASE] = sizeof(u32),
[XFRM_MSG_MAPPING - XFRM_MSG_BASE] = XMSGSIZE(xfrm_user_mapping)
};
static struct nlmsghdr *xfrm_nlmsg_put_compat(struct sk_buff *skb,
const struct nlmsghdr *nlh_src, u16 type)
{
int payload = compat_msg_min[type];
int src_len = xfrm_msg_min[type];
struct nlmsghdr *nlh_dst;
/* Compat messages are shorter or equal to native (+padding) */
if (WARN_ON_ONCE(src_len < payload))
return ERR_PTR(-EMSGSIZE);
nlh_dst = nlmsg_put(skb, nlh_src->nlmsg_pid, nlh_src->nlmsg_seq,
nlh_src->nlmsg_type, payload, nlh_src->nlmsg_flags);
if (!nlh_dst)
return ERR_PTR(-EMSGSIZE);
memset(nlmsg_data(nlh_dst), 0, payload);
switch (nlh_src->nlmsg_type) {
/* Compat message has the same layout as native */
case XFRM_MSG_DELSA:
case XFRM_MSG_DELPOLICY:
case XFRM_MSG_FLUSHSA:
case XFRM_MSG_FLUSHPOLICY:
case XFRM_MSG_NEWAE:
case XFRM_MSG_REPORT:
case XFRM_MSG_MIGRATE:
case XFRM_MSG_NEWSADINFO:
case XFRM_MSG_NEWSPDINFO:
case XFRM_MSG_MAPPING:
WARN_ON_ONCE(src_len != payload);
memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), src_len);
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:
WARN_ON_ONCE(src_len != payload + 4);
memcpy(nlmsg_data(nlh_dst), nlmsg_data(nlh_src), payload);
break;
case XFRM_MSG_EXPIRE: {
const struct xfrm_user_expire *src_ue = nlmsg_data(nlh_src);
struct compat_xfrm_user_expire *dst_ue = nlmsg_data(nlh_dst);
/* compat_xfrm_user_expire has 4-byte smaller state */
memcpy(dst_ue, src_ue, sizeof(dst_ue->state));
dst_ue->hard = src_ue->hard;
break;
}
case XFRM_MSG_ACQUIRE: {
const struct xfrm_user_acquire *src_ua = nlmsg_data(nlh_src);
struct compat_xfrm_user_acquire *dst_ua = nlmsg_data(nlh_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 xfrm_user_polexpire *src_upe = nlmsg_data(nlh_src);
struct compat_xfrm_user_polexpire *dst_upe = nlmsg_data(nlh_dst);
/* compat_xfrm_user_polexpire has 4-byte smaller state */
memcpy(dst_upe, src_upe, sizeof(dst_upe->pol));
dst_upe->hard = src_upe->hard;
break;
}
case XFRM_MSG_ALLOCSPI: {
const struct xfrm_userspi_info *src_usi = nlmsg_data(nlh_src);
struct compat_xfrm_userspi_info *dst_usi = nlmsg_data(nlh_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;
}
/* Not being sent by kernel */
case XFRM_MSG_GETSA:
case XFRM_MSG_GETPOLICY:
case XFRM_MSG_GETAE:
case XFRM_MSG_GETSADINFO:
case XFRM_MSG_GETSPDINFO:
default:
WARN_ONCE(1, "unsupported nlmsg_type %d", nlh_src->nlmsg_type);
return ERR_PTR(-EOPNOTSUPP);
}
return nlh_dst;
}
static int xfrm_nla_cpy(struct sk_buff *dst, const struct nlattr *src, int len)
{
return nla_put(dst, src->nla_type, len, nla_data(src));
}
static int xfrm_xlate64_attr(struct sk_buff *dst, const struct nlattr *src)
{
switch (src->nla_type) {
case XFRMA_PAD:
/* Ignore */
return 0;
case XFRMA_ALG_AUTH:
case XFRMA_ALG_CRYPT:
case XFRMA_ALG_COMP:
case XFRMA_ENCAP:
case XFRMA_TMPL:
return xfrm_nla_cpy(dst, src, nla_len(src));
case XFRMA_SA:
return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_usersa_info));
case XFRMA_POLICY:
return xfrm_nla_cpy(dst, src, XMSGSIZE(compat_xfrm_userpolicy_info));
case XFRMA_SEC_CTX:
return xfrm_nla_cpy(dst, src, nla_len(src));
case XFRMA_LTIME_VAL:
return nla_put_64bit(dst, src->nla_type, nla_len(src),
nla_data(src), XFRMA_PAD);
case XFRMA_REPLAY_VAL:
case XFRMA_REPLAY_THRESH:
case XFRMA_ETIMER_THRESH:
case XFRMA_SRCADDR:
case XFRMA_COADDR:
return xfrm_nla_cpy(dst, src, nla_len(src));
case XFRMA_LASTUSED:
return nla_put_64bit(dst, src->nla_type, nla_len(src),
nla_data(src), XFRMA_PAD);
case XFRMA_POLICY_TYPE:
case XFRMA_MIGRATE:
case XFRMA_ALG_AEAD:
case XFRMA_KMADDRESS:
case XFRMA_ALG_AUTH_TRUNC:
case XFRMA_MARK:
case XFRMA_TFCPAD:
case XFRMA_REPLAY_ESN_VAL:
case XFRMA_SA_EXTRA_FLAGS:
case XFRMA_PROTO:
case XFRMA_ADDRESS_FILTER:
case XFRMA_OFFLOAD_DEV:
case XFRMA_SET_MARK:
case XFRMA_SET_MARK_MASK:
case XFRMA_IF_ID:
return xfrm_nla_cpy(dst, src, nla_len(src));
default:
BUILD_BUG_ON(XFRMA_MAX != XFRMA_IF_ID);
WARN_ONCE(1, "unsupported nla_type %d", src->nla_type);
return -EOPNOTSUPP;
}
}
/* Take kernel-built (64bit layout) and create 32bit layout for userspace */
static int xfrm_xlate64(struct sk_buff *dst, const struct nlmsghdr *nlh_src)
{
u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
const struct nlattr *nla, *attrs;
struct nlmsghdr *nlh_dst;
int len, remaining;
nlh_dst = xfrm_nlmsg_put_compat(dst, nlh_src, type);
if (IS_ERR(nlh_dst))
return PTR_ERR(nlh_dst);
attrs = nlmsg_attrdata(nlh_src, xfrm_msg_min[type]);
len = nlmsg_attrlen(nlh_src, xfrm_msg_min[type]);
nla_for_each_attr(nla, attrs, len, remaining) {
int err = xfrm_xlate64_attr(dst, nla);
if (err)
return err;
}
nlmsg_end(dst, nlh_dst);
return 0;
}
static int xfrm_alloc_compat(struct sk_buff *skb, const struct nlmsghdr *nlh_src)
{
u16 type = nlh_src->nlmsg_type - XFRM_MSG_BASE;
struct sk_buff *new = NULL;
int err;
if (WARN_ON_ONCE(type >= ARRAY_SIZE(xfrm_msg_min)))
return -EOPNOTSUPP;
if (skb_shinfo(skb)->frag_list == NULL) {
new = alloc_skb(skb->len + skb_tailroom(skb), GFP_ATOMIC);
if (!new)
return -ENOMEM;
skb_shinfo(skb)->frag_list = new;
}
err = xfrm_xlate64(skb_shinfo(skb)->frag_list, nlh_src);
if (err) {
if (new) {
kfree_skb(new);
skb_shinfo(skb)->frag_list = NULL;
}
return err;
}
return 0;
}
static struct xfrm_translator xfrm_translator = {
.owner = THIS_MODULE,
.alloc_compat = xfrm_alloc_compat,
};
static int __init xfrm_compat_init(void)

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@ -1083,12 +1083,24 @@ static inline int xfrm_nlmsg_multicast(struct net *net, struct sk_buff *skb,
u32 pid, unsigned int group)
{
struct sock *nlsk = rcu_dereference(net->xfrm.nlsk);
struct xfrm_translator *xtr;
if (!nlsk) {
kfree_skb(skb);
return -EPIPE;
}
xtr = xfrm_get_translator();
if (xtr) {
int err = xtr->alloc_compat(skb, nlmsg_hdr(skb));
xfrm_put_translator(xtr);
if (err) {
kfree_skb(skb);
return err;
}
}
return nlmsg_multicast(nlsk, skb, pid, group, GFP_ATOMIC);
}
@ -2533,7 +2545,7 @@ static int xfrm_send_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
#define XMSGSIZE(type) sizeof(struct type)
static const int xfrm_msg_min[XFRM_NR_MSGTYPES] = {
const int xfrm_msg_min[XFRM_NR_MSGTYPES] = {
[XFRM_MSG_NEWSA - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_info),
[XFRM_MSG_DELSA - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_id),
[XFRM_MSG_GETSA - XFRM_MSG_BASE] = XMSGSIZE(xfrm_usersa_id),
@ -2556,6 +2568,7 @@ static const int xfrm_msg_min[XFRM_NR_MSGTYPES] = {
[XFRM_MSG_NEWSPDINFO - XFRM_MSG_BASE] = sizeof(u32),
[XFRM_MSG_GETSPDINFO - XFRM_MSG_BASE] = sizeof(u32),
};
EXPORT_SYMBOL_GPL(xfrm_msg_min);
#undef XMSGSIZE