revoke_pty: use killpg() not kill() to send HUP to the process group

millert · millert · commit fb208d383af2 · 2025-07-14T17:00:17.000-06:00
Also make sure we never call killpg(-1, SIGHUP), which would send SIGHUP to process 1 (init). It is possible for cmnd_pid to be -1 in certain error conditions where sudo killed the command itself. This may explain GitHub issue #458.
diff --git a/src/exec_pty.c b/src/exec_pty.c
@@ -358,9 +358,11 @@ revoke_pty(struct exec_closure *ec)
 	    pgrp = tcpgrp;
 	close(io_fds[SFD_LEADER]);
     }
-    sudo_debug_printf(SUDO_DEBUG_NOTICE, "%s: killpg(%d, SIGHUP)",
-	__func__, (int)pgrp);
-    kill(pgrp, SIGHUP);
+    if (pgrp != -1) {
+	sudo_debug_printf(SUDO_DEBUG_NOTICE, "%s: killpg(%d, SIGHUP)",
+	    __func__, (int)pgrp);
+	killpg(pgrp, SIGHUP);
+    }
 }
 
 /*

Original file line number	Diff line number	Diff line change
`@@ -358,9 +358,11 @@ revoke_pty(struct exec_closure *ec)`
`358`	`358`	`pgrp = tcpgrp;`
`359`	`359`	`close(io_fds[SFD_LEADER]);`
`360`	`360`	`}`
`361`		`- sudo_debug_printf(SUDO_DEBUG_NOTICE, "%s: killpg(%d, SIGHUP)",`
`362`		`- __func__, (int)pgrp);`
`363`		`- kill(pgrp, SIGHUP);`
	`361`	`+ if (pgrp != -1) {`
	`362`	`+ sudo_debug_printf(SUDO_DEBUG_NOTICE, "%s: killpg(%d, SIGHUP)",`
	`363`	`+ __func__, (int)pgrp);`
	`364`	`+ killpg(pgrp, SIGHUP);`
	`365`	`+ }`
`364`	`366`	`}`
`365`	`367`
`366`	`368`	`/*`