In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone<\/p>\n
kmalloc_flex() in metadata_dst_alloc() sets __counted_by for the
\nstructure to the options_len, which is then initialized to zero.
\nLater, we’re initializing the structure by copying the tunnel info
\ntogether with the options, and this triggers a warning for a potential
\nmemcpy overflow, since the compiler estimates that the options can’t
\nfit into the structure, even though the memory for them is actually
\nallocated.<\/p>\n
memcpy: detected buffer overflow: 104 byte write of buffer size 96
\n WARNING: CPU: X PID: Y at lib\/string_helpers.c:1036 __fortify_report
\n skb_tunnel_info_unclone+0x179\/0x190
\n geneve_xmit+0x7fe\/0xe00<\/p>\n
The issue is triggered when built with clang and source fortification.<\/p>\n
Fix that by doing the copy in two stages: first – the main data with
\nthe options_len, then the options. This way the correct length should
\nbe known at the time of the copy.<\/p>\n
It would be better if the options_len never changed after allocation,
\nbut the allocation code is a little separate from the initialization
\nand it would be awkward and potentially dangerous to return a struct
\nwith options_len set to a non-zero value from the metadata_dst_alloc().<\/p>\n
Another option would be to use ip_tunnel_info_opts_set(), but it is
\ndoing too many unnecessary operations for the use case here.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
net: dst_metadata: fix false-positive memcpy overflow in tun_dst_unclone<\/p>\n
kmalloc_flex() in metadata_dst_alloc() sets __counted_by <\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-12306","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/12306","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=12306"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12306"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12306"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}