[PATCH v14 07/14] fixup: Sanity check passt-repair reply message

[David Gibson <david@gibson.dropbear.id.au>]

At the moment we discard the reply message; the fact that it exists is the
only thing we check.  Check it has the expected value to be a bit more
thorough.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 repair.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/repair.c b/repair.c
index f473e1f4..d2886173 100644
--- a/repair.c
+++ b/repair.c
@@ -150,6 +150,7 @@ int repair_flush(struct ctx *c)
 	     __attribute__ ((aligned(__alignof__(struct cmsghdr))));
 	struct cmsghdr *cmsg;
 	struct msghdr msg;
+	int8_t reply;
 
 	if (!repair_nfds)
 		return 0;
@@ -172,13 +173,19 @@ int repair_flush(struct ctx *c)
 		return ret;
 	}
 
-	if (recv(c->fd_repair, &((int8_t){ 0 }), 1, 0) < 0) {
+	if (recv(c->fd_repair, &reply, sizeof(reply), 0) < 0) {
 		int ret = -errno;
 		err_perror("Failed to receive reply from TCP_REPAIR helper");
 		repair_close(c);
 		return ret;
 	}
 
+	if (reply != repair_cmd) {
+		err("Unexpected reply from TCP_REPAIR helper: %d", reply);
+		repair_close(c);
+		return -ENXIO;
+	}
+
 	return 0;
 }
 
-- 
@@ -150,6 +150,7 @@ int repair_flush(struct ctx *c)
 	     __attribute__ ((aligned(__alignof__(struct cmsghdr))));
 	struct cmsghdr *cmsg;
 	struct msghdr msg;
+	int8_t reply;
 
 	if (!repair_nfds)
 		return 0;
@@ -172,13 +173,19 @@ int repair_flush(struct ctx *c)
 		return ret;
 	}
 
-	if (recv(c->fd_repair, &((int8_t){ 0 }), 1, 0) < 0) {
+	if (recv(c->fd_repair, &reply, sizeof(reply), 0) < 0) {
 		int ret = -errno;
 		err_perror("Failed to receive reply from TCP_REPAIR helper");
 		repair_close(c);
 		return ret;
 	}
 
+	if (reply != repair_cmd) {
+		err("Unexpected reply from TCP_REPAIR helper: %d", reply);
+		repair_close(c);
+		return -ENXIO;
+	}
+
 	return 0;
 }
 
-- 
2.48.1