[PATCH v3 06/11] SUNRPC: Capture CMSG metadata on client-side receive
From: Chuck Lever <cel@kernel.org>
Date: 2023-05-30 14:08:02
Subsystem:
kernel nfsd, sunrpc, and lockd servers, networking [general], nfs, sunrpc, and lockd clients, the rest · Maintainers:
Chuck Lever, Jeff Layton, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Trond Myklebust, Anna Schumaker, Linus Torvalds
From: Chuck Lever <chuck.lever@oracle.com> kTLS sockets use CMSG to report decryption errors and the need for session re-keying. For RPC-with-TLS, an "application data" message contains a ULP payload, and that is passed along to the RPC client. An "alert" message triggers connection reset. Everything else is discarded. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> --- net/sunrpc/xprtsock.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 47 insertions(+), 2 deletions(-)
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 37f608c2c0a0..6f2fc863b47e 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c@@ -47,6 +47,8 @@ #include <net/checksum.h> #include <net/udp.h> #include <net/tcp.h> +#include <net/tls.h> + #include <linux/bvec.h> #include <linux/highmem.h> #include <linux/uio.h>
@@ -342,13 +344,56 @@ xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp) return want; } +static int +xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg, + struct cmsghdr *cmsg, int ret) +{ + if (cmsg->cmsg_level == SOL_TLS && + cmsg->cmsg_type == TLS_GET_RECORD_TYPE) { + u8 content_type = *((u8 *)CMSG_DATA(cmsg)); + + switch (content_type) { + case TLS_RECORD_TYPE_DATA: + /* TLS sets EOR at the end of each application data + * record, even though there might be more frames + * waiting to be decrypted. + */ + msg->msg_flags &= ~MSG_EOR; + break; + case TLS_RECORD_TYPE_ALERT: + ret = -ENOTCONN; + break; + default: + ret = -EAGAIN; + } + } + return ret; +} + +static int +xs_sock_recv_cmsg(struct socket *sock, struct msghdr *msg, int flags) +{ + union { + struct cmsghdr cmsg; + u8 buf[CMSG_SPACE(sizeof(u8))]; + } u; + int ret; + + msg->msg_control = &u; + msg->msg_controllen = sizeof(u); + ret = sock_recvmsg(sock, msg, flags); + if (msg->msg_controllen != sizeof(u)) + ret = xs_sock_process_cmsg(sock, msg, &u.cmsg, ret); + return ret; +} + static ssize_t xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek) { ssize_t ret; if (seek != 0) iov_iter_advance(&msg->msg_iter, seek); - ret = sock_recvmsg(sock, msg, flags); + ret = xs_sock_recv_cmsg(sock, msg, flags); return ret > 0 ? ret + seek : ret; }
@@ -374,7 +419,7 @@ xs_read_discard(struct socket *sock, struct msghdr *msg, int flags, size_t count) { iov_iter_discard(&msg->msg_iter, ITER_DEST, count); - return sock_recvmsg(sock, msg, flags); + return xs_sock_recv_cmsg(sock, msg, flags); } #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE