In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
Bluetooth: MSFT: validate evt_prefix_len against the response length<\/p>\n
read_supported_features() only checks that the response covers the fixed
\npart of struct msft_rp_read_supported_features, which is 11 bytes:<\/p>\n
\tif (skb->len evt_prefix_len is an
\nunvalidated u8 taken straight out of that response, so<\/p>\n
\tmsft->evt_prefix = kmemdup(rp->evt_prefix, rp->evt_prefix_len,
\n\t\t\t\t GFP_KERNEL);<\/p>\n
copies up to 255 bytes from a reply that may have carried none of them.
\nWhat is copied is data the controller never sent, and it is then used to
\nmatch incoming vendor events in msft_vendor_evt().<\/p>\n
This is not an out-of-bounds access. An skb data allocation always has
\nat least SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) bytes past the
\npayload, which is more than the 255 byte maximum, so the read stays
\ninside the allocation and KASAN does not report it. It is still a read
\nof bytes the host was never given, with the length fully controlled by
\nthe controller.<\/p>\n
Reject a response that is too short for the prefix it declares.<\/p>\n
Verified with an emulated controller over \/dev\/vhci on a KASAN kernel,
\nwith vhci made to advertise an MSFT opcode the way btintel, btqca, btmtk
\nand btrtl do unconditionally. A reply of exactly 11 bytes declaring
\nevt_prefix_len = 255 reaches kmemdup and copies 255 bytes
\n(“skb->len=11 evt_prefix_len=255”, with the copied buffer dumped); since
\nthe reply ends at the fixed part, all 255 come from past the end of the
\nresponse. No KASAN report is produced, as expected from the allocation
\nslack described above. With this patch the response is rejected with
\n“MSFT event prefix length mismatch” and msft->evt_prefix is left unset.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
Bluetooth: MSFT: validate evt_prefix_len against the response length<\/p>\n
read_supported_features() only checks that the response cover<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-25660","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/25660","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=25660"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25660"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25660"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}