From a0879abae40625f586a0af5621e7a29f8b5a568f Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Sat, 7 Mar 2020 23:58:47 +0100
Subject: [PATCH] devproc: don't allow /proc/$pid/ctl to be opens for reading

---
 sys/src/9/port/devproc.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sys/src/9/port/devproc.c b/sys/src/9/port/devproc.c
index 01dcede44..b2f6ebf91 100644
--- a/sys/src/9/port/devproc.c
+++ b/sys/src/9/port/devproc.c
@@ -447,7 +447,6 @@ procopen(Chan *c, int omode0)
 	case Qnoteid:
 		if(omode == OREAD)
 			break;
-	case Qctl:
 	case Qnote:
 		if(p->kp)
 			error(Eperm);
@@ -459,6 +458,11 @@ procopen(Chan *c, int omode0)
 		pid = p->noteid;
 		break;
 
+	case Qctl:
+		if(p->kp || omode != OWRITE)
+			error(Eperm);
+		break;
+
 	case Qmem:
 	case Qregs:
 	case Qfpregs: