[PATCH] signal: adjust si_code restriction in pidfd_send_signal()

[Oleg Nesterov]

Since we now allow specifying PIDFD_SEND_PROCESS_GROUP for
pidfd_send_signal() to send signals to process groups we need to adjust
the check restricting si_code emulation by userspace to account for
PIDTYPE_PGID.

Reported-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240214123655.GB16265@xxxxxxxxxx
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
 kernel/signal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index cf6539a6b1cb..5f5620c81d3a 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3956,7 +3956,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
 
 		/* Only allow sending arbitrary signals to yourself. */
 		ret = -EPERM;
-		if ((task_pid(current) != pid) &&
+		if (((task_pid(current) != pid) || type > PIDTYPE_TGID) &&
 		    (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
 			goto err;
 	} else {
-- 
2.43.0


--ovt7oib6ffqntnud--