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net/xfrm/compat: Copy xfrm_spdattr_type_t atributes

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The attribute-translator has to take in mind maxtype, that is
xfrm_link::nla_max. When it is set, attributes are not of xfrm_attr_type_t.
Currently, they can be only XFRMA_SPD_MAX (message XFRM_MSG_NEWSPDINFO),
their UABI is the same for 64/32-bit, so just copy them.

Thanks to YueHaibing for reporting this:
In xfrm_user_rcv_msg_compat() if maxtype is not zero and less than
XFRMA_MAX, nlmsg_parse_deprecated() do not initialize attrs array fully.
xfrm_xlate32() will access uninit 'attrs[i]' while iterating all attrs
array.

KASAN: probably user-memory-access in range [0x0000000041b58ab0-0x0000000041b58ab7]
CPU: 0 PID: 15799 Comm: syz-executor.2 Tainted: G        W         5.14.0-rc1-syzkaller #0
RIP: 0010:nla_type include/net/netlink.h:1130 [inline]
RIP: 0010:xfrm_xlate32_attr net/xfrm/xfrm_compat.c:410 [inline]
RIP: 0010:xfrm_xlate32 net/xfrm/xfrm_compat.c:532 [inline]
RIP: 0010:xfrm_user_rcv_msg_compat+0x5e5/0x1070 net/xfrm/xfrm_compat.c:577
[...]
Call Trace:
 xfrm_user_rcv_msg+0x556/0x8b0 net/xfrm/xfrm_user.c:2774
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
 xfrm_netlink_rcv+0x6b/0x90 net/xfrm/xfrm_user.c:2824
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:702 [inline]

Fixes: 5106f4a8ac ("xfrm/compat: Add 32=>64-bit messages translator")
Cc: <stable@kernel.org>
Reported-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Dmitry Safonov 2021-07-17 16:02:21 +01:00 committed by Steffen Klassert
parent 2580d3f400
commit 4e9505064f
1 changed files with 44 additions and 5 deletions
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49
net/xfrm/xfrm_compat.c
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@ -298,8 +298,16 @@ static int xfrm_xlate64(struct sk_buff *dst, const struct nlmsghdr *nlh_src)
len = nlmsg_attrlen(nlh_src, xfrm_msg_min[type]);
nla_for_each_attr(nla, attrs, len, remaining) {
int err = xfrm_xlate64_attr(dst, nla);
int err;
switch (type) {
case XFRM_MSG_NEWSPDINFO:
err = xfrm_nla_cpy(dst, nla, nla_len(nla));
break;
default:
err = xfrm_xlate64_attr(dst, nla);
break;
}
if (err)
return err;
}
@ -341,7 +349,8 @@ static int xfrm_alloc_compat(struct sk_buff *skb, const struct nlmsghdr *nlh_src
/* 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])
struct nlattr *attrs[XFRMA_MAX + 1],
int maxtype)
{
size_t len = nlmsg_len(src);
@ -358,10 +367,20 @@ static size_t xfrm_user_rcv_calculate_len64(const struct nlmsghdr *src,
case XFRM_MSG_POLEXPIRE:
len += 8;
break;
case XFRM_MSG_NEWSPDINFO:
/* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */
return len;
default:
break;
}
/* Unexpected for anything, but XFRM_MSG_NEWSPDINFO, please
* correct both 64=>32-bit and 32=>64-bit translators to copy
* new attributes.
*/
if (WARN_ON_ONCE(maxtype))
return len;
if (attrs[XFRMA_SA])
len += 4;
if (attrs[XFRMA_POLICY])
@ -440,7 +459,8 @@ static int xfrm_xlate32_attr(void *dst, const struct nlattr *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 size, u8 type, int maxtype,
struct netlink_ext_ack *extack)
{
size_t pos;
int i;
@ -520,6 +540,25 @@ static int xfrm_xlate32(struct nlmsghdr *dst, const struct nlmsghdr *src,
}
pos = dst->nlmsg_len;
if (maxtype) {
/* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */
WARN_ON_ONCE(src->nlmsg_type != XFRM_MSG_NEWSPDINFO);
for (i = 1; i <= maxtype; i++) {
int err;
if (!attrs[i])
continue;
/* just copy - no need for translation */
err = xfrm_attr_cpy32(dst, &pos, attrs[i], size,
nla_len(attrs[i]), nla_len(attrs[i]));
if (err)
return err;
}
return 0;
}
for (i = 1; i < XFRMA_MAX + 1; i++) {
int err;
@ -564,7 +603,7 @@ static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32,
if (err < 0)
return ERR_PTR(err);
len = xfrm_user_rcv_calculate_len64(h32, attrs);
len = xfrm_user_rcv_calculate_len64(h32, attrs, maxtype);
/* The message doesn't need translation */
if (len == nlmsg_len(h32))
return NULL;
@ -574,7 +613,7 @@ static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32,
if (!h64)
return ERR_PTR(-ENOMEM);
err = xfrm_xlate32(h64, h32, attrs, len, type, extack);
err = xfrm_xlate32(h64, h32, attrs, len, type, maxtype, extack);
if (err < 0) {
kvfree(h64);
return ERR_PTR(err);