From: Dmitry Safonov dima@arista.com
commit 4e9505064f58d1252805952f8547a5b7dbc5c111 upstream.
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: 5106f4a8acff ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/xfrm/xfrm_compat.c | 49 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 44 insertions(+), 5 deletions(-)
--- a/net/xfrm/xfrm_compat.c +++ b/net/xfrm/xfrm_compat.c @@ -298,8 +298,16 @@ static int xfrm_xlate64(struct sk_buff * 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_b
/* 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_le 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,
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 } 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_ms 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_ms 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);