From: François LEGAL <[email protected]> The RTNET sendmsg/recvmsg protocol handlers used to call copy_to/from_user on the struct user_msghdr argument. The syscall entry code already does this copy, so calling again the copy_to/from_user in handlers triggers SPECTRE mitigation protection. This patch removes the calls in the handlers
This patch has been tested with 4.4.x kernel Signed-off-by: François LEGAL <[email protected]> --- kernel/drivers/net/stack/packet/af_packet.c | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-) diff --git a/kernel/drivers/net/stack/packet/af_packet.c b/kernel/drivers/net/stack/packet/af_packet.c index b8de8a0..cc74873 100644 --- a/kernel/drivers/net/stack/packet/af_packet.c +++ b/kernel/drivers/net/stack/packet/af_packet.c @@ -294,7 +294,7 @@ static int rt_packet_ioctl(struct rtdm_fd *fd, unsigned int request, /*** * rt_packet_recvmsg */ -static ssize_t rt_packet_recvmsg(struct rtdm_fd *fd, struct user_msghdr *u_msg, +static ssize_t rt_packet_recvmsg(struct rtdm_fd *fd, struct user_msghdr *msg, int msg_flags) { struct rtsocket *sock = rtdm_fd_to_private(fd); @@ -304,14 +304,9 @@ static ssize_t rt_packet_recvmsg(struct rtdm_fd *fd, struct user_msghdr *u_msg, struct sockaddr_ll sll; int ret, flags; nanosecs_rel_t timeout = sock->timeout; - struct user_msghdr _msg, *msg; socklen_t namelen; struct iovec iov_fast[RTDM_IOV_FASTMAX], *iov; - msg = rtnet_get_arg(fd, &_msg, u_msg, sizeof(_msg)); - if (IS_ERR(msg)) - return PTR_ERR(msg); - if (msg->msg_iovlen < 0) return -EINVAL; @@ -359,7 +354,7 @@ static ssize_t rt_packet_recvmsg(struct rtdm_fd *fd, struct user_msghdr *u_msg, goto fail; namelen = sizeof(sll); - ret = rtnet_put_arg(fd, &u_msg->msg_namelen, &namelen, + ret = rtnet_put_arg(fd, &msg->msg_namelen, &namelen, sizeof(namelen)); if (ret) goto fail; @@ -380,7 +375,7 @@ static ssize_t rt_packet_recvmsg(struct rtdm_fd *fd, struct user_msghdr *u_msg, if (copy_len > len) { copy_len = len; flags = msg->msg_flags | MSG_TRUNC; - ret = rtnet_put_arg(fd, &u_msg->msg_flags, &flags, + ret = rtnet_put_arg(fd, &msg->msg_flags, &flags, sizeof(flags)); if (ret) goto fail; @@ -419,7 +414,6 @@ static ssize_t rt_packet_sendmsg(struct rtdm_fd *fd, unsigned char *addr; int ifindex; ssize_t ret; - struct user_msghdr _msg; struct iovec iov_fast[RTDM_IOV_FASTMAX], *iov; if (msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */ @@ -427,10 +421,6 @@ static ssize_t rt_packet_sendmsg(struct rtdm_fd *fd, if (msg_flags & ~MSG_DONTWAIT) return -EINVAL; - msg = rtnet_get_arg(fd, &_msg, msg, sizeof(*msg)); - if (IS_ERR(msg)) - return PTR_ERR(msg); - if (msg->msg_iovlen < 0) return -EINVAL;
