In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net: ipv6: keep room for the mac header in dst_dev_overhead()<\/p>\n
The seg6, ioam6 and rpl lwtunnels size their skb_cow_head() request as
\nthe length they are about to push plus dst_dev_overhead(), then push the
\nnew headers and rebuild the mac header below them with
\nskb_mac_header_rebuild(). That rebuild needs skb->mac_len of headroom,
\nbut dst_dev_overhead() leaves LL_RESERVED_SPACE() of the egress device,
\n16 bytes for plain Ethernet.<\/p>\n
Where the mac header is longer than that, as it is on ingress through a
\nVLAN device with reorder_hdr off, the rebuild runs out of room:
\nskb_set_mac_header(skb, -skb->mac_len) computes a negative offset,
\nstores it unchecked in the u16 skb->mac_header, and the memmove that
\nfollows writes skb->mac_len bytes about 64 KB past skb->head.
\nForwarding plain ping6 traffic through such a device reproduces it on
\nall five seg6 encapsulation modes and on the rpl and ioam6 inline paths;
\nskb->mac_header comes back as 65534 on a 704-byte head.<\/p>\n
Return the larger of the two. The helper already returns skb->mac_len
\nwhen it has no dst, so this only makes the other branch agree, and it
\ncovers every caller rather than each call site in turn.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net: ipv6: keep room for the mac header in dst_dev_overhead()<\/p>\n
The seg6, ioam6 and rpl lwtunnels size their skb_cow_head() request <\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-41042","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/41042","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=41042"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41042"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41042"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}