CVE-2022-48819 — tcp: take care of mixed splice()/sendmsg(MSG_ZEROCOPY) case
In the Linux kernel, the following vulnerability has been resolved: tcp: take care of mixed splice()/sendmsg(MSG_ZEROCOPY) case syzbot found that mixing sendpage() and sendmsg…
Published: 2024-07-16 · CVSS: Unscored
In the Linux kernel, the following vulnerability has been resolved: tcp: take care of mixed splice()/sendmsg(MSG_ZEROCOPY) case syzbot found that mixing sendpage() and sendmsg(MSG_ZEROCOPY) calls over the same TCP socket would again trigger the infamous warning in inet_sock_destruct() WARN_ON(sk_forward_alloc_get(sk)); While Talal took into account a mix of regular copied data and MSG_ZEROCOPY one in the same skb, the sendpage() path has been forgotten. We want the charging to happen for sendpage(), because pages could be coming from a pipe. What is missing is the downgrading of pure zerocopy status to make sure sk_forward_alloc will stay synced. Add tcp_downgrade_zcopy_pure() helper so that we can use it from the two callers.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7