In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
rxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg<\/p>\n
This improves the fix for CVE-2026-43500.<\/p>\n
Fix the pagecache corruption from in-place decryption of a DATA packet
\ntransmitted locally by splice() by getting rid of the packet sharing in the
\nI\/O thread and unconditionally extracting the packet content into a bounce
\nbuffer in which the buffer is decrypted. recvmsg() (or the kernel
\nequivalent) then copies the data from the bounce buffer to the destination
\nbuffer. The sk_buff then remains unmodified.<\/p>\n
This has an additional advantage in that the packet is then arranged in the
\nbuffer with the correct alignment required for the crypto algorithms to
\nprocess directly. The performance of the crypto does seem to be a little
\nfaster and, surprisingly, the unencrypted performance doesn’t seem to
\nchange much – possibly due to removing complexity from the I\/O thread.<\/p>\n
Yet another advantage is that the I\/O thread doesn’t have to copy packets
\nwhich would slow down packet distribution, ACK generation, etc..<\/p>\n
The buffer belongs to the call and is allocated initially at 2K,
\nsufficiently large to hold a whole jumbo subpacket, but the buffer will be
\nincreased in size if needed. However, to take this work, MSG_PEEK may
\ncause a later packet to be decrypted into the buffer, in which case the
\nearlier one will need re-decrypting for a subsequent recvmsg().<\/p>\n
Note that rx_pkt_offset may legitimately see 0 as a valid offset now, so
\nswitch to using USHRT_MAX to indicate an invalid offset.<\/p>\n
Note also that I would generally prefer to replace the buffers of the
\ncurrent sk_buff with a new kmalloc’d buffer of the right size, ditching the
\nold data and frags as this makes the handling of MSG_PEEK easier and
\nremoves the re-decryption issue, but this looks like quite a complicated
\nthing to achieve. skb_morph() looks half way to what I want, but I don’t
\nwant to have to allocate a new sk_buff.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
rxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg<\/p>\n
This improves the fix for CVE-2026-43500.<\/p>\n
Fix the pageca<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-15019","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/15019","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=15019"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=15019"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=15019"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}