tun: read vnet_hdr_sz once

When IFF_VNET_HDR is enabled, a virtio_net header must precede data.
Data length is verified to be greater than or equal to expected header
length tun->vnet_hdr_sz before copying.

Read this value once and cache locally, as it can be updated between
the test and use (TOCTOU).

Signed-off-by: Willem de Bruijn <willemb@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
CC: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c

path: root/tools/lib/subcmd/sigchain.h

#ifndef __SUBCMD_SIGCHAIN_H
#define __SUBCMD_SIGCHAIN_H

typedef void (*sigchain_fun)(int);

int sigchain_pop(int sig);

void sigchain_push_common(sigchain_fun f);

#endif /* __SUBCMD_SIGCHAIN_H */