In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
xfrm: Check for underflow in xfrm_state_mtu<\/p>\n
Leo Lin reported OOB write issue in esp component:<\/p>\n
xfrm_state_mtu() returns u32 but performs its arithmetic in unsigned
\n modulo-2^32 space using an attacker-influenced “header_len + authsize +
\n net_adj” subtracted from a small “mtu” argument. A nobody user can
\n install an IPv4 ESP tunnel SA with a large authentication key
\n (XFRMA_ALG_AUTH_TRUNC, e.g. hmac(sha512), 64-byte key, 64-byte trunc),
\n configure a small interface MTU (68 bytes), and set XFRMA_TFCPAD to a
\n large value. When a single UDP datagram is then sent through the
\n tunnel, xfrm_state_mtu() underflows to a near-2^32 value, and
\n esp_output() consumes it as a signed int via:<\/p>\n
padto = min(x->tfcpad, xfrm_state_mtu(x, mtu_cached))
\n esp.tfclen = padto – skb->len (assigned to int)<\/p>\n
esp.tfclen ends up negative (e.g. -207). It is sign-extended to size_t
\n when passed to memset() inside esp_output_fill_trailer(), producing a
\n ~16 EB write of zeroes at skb_tail_pointer(skb). KASAN logs it as
\n “Write of size 18446744073709551537 at addr ffff888…”.<\/p>\n
Check for underflow and return 1. This causes the sendmsg attempt to
\nfail with ENETUNREACH.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
xfrm: Check for underflow in xfrm_state_mtu<\/p>\n
Leo Lin reported OOB write issue in esp component:<\/p>\n
xfrm_state_mtu() returns u32 but<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-15008","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/15008","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=15008"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=15008"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=15008"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}