On 7/15/25 10:11 AM, Pranav Tyagi wrote: > A NULL page from sg_page() in sk_msg_recvmsg() can reach > __kmap_local_page_prot() and crash the kernel. Add a check for the page > before calling copy_page_to_iter() and fail early with -EFAULT to > prevent the crash. Interesting. I thought the sge in this case are build from the kernel, I did not expect a null page to be possible. Can you describe in the commit message how such bad sges are created? > > Reported-by: syzbot+b18872ea9631b5dcef3b@xxxxxxxxxxxxxxxxxxxxxxxxx > Closes: https://syzkaller.appspot.com/bug?extid=b18872ea9631b5dcef3b > Fixes: 2bc793e3272a ("skmsg: Extract __tcp_bpf_recvmsg() and tcp_bpf_wait_data()") > Signed-off-by: Pranav Tyagi <pranav.tyagi03@xxxxxxxxx> Does not apply to net. Please rebase and resend, adding the target tree in the subj prefix and specifying a revision number. Thanks, Paolo
