net: validate SO_TXTIME clockid coming from userspace

Currently there are no strict checks while setting SO_TXTIME
from userspace. With the recent development in skb->tstamp_type
clockid with unsupported clocks results in warn_on_once, which causes
unnecessary aborts in some systems which enables panic on warns.

Add validation in setsockopt to support only CLOCK_REALTIME,
CLOCK_MONOTONIC and CLOCK_TAI to be set from userspace.

Link: https://lore.kernel.org/netdev/bc037db4-58bb-4861-ac31-a361a93841d3@linux.dev/
Link: https://lore.kernel.org/lkml/6bdba7b6-fd22-4ea5-a356-12268674def1@quicinc.com/
Fixes: 1693c5db6ab8 ("net: Add additional bit to support clockid_t timestamp type")
Reported-by: syzbot+d7b227731ec589e7f4f0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d7b227731ec589e7f4f0
Reported-by: syzbot+30a35a2e9c5067cc43fa@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=30a35a2e9c5067cc43fa
Signed-off-by: Abhishek Chauhan <quic_abchauha@quicinc.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240529183130.1717083-1-quic_abchauha@quicinc.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/sock.c b/net/core/sock.c
index 521e637..69baddc 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1083,6 +1083,17 @@ bool sockopt_capable(int cap)
 }
 EXPORT_SYMBOL(sockopt_capable);
 
+static int sockopt_validate_clockid(__kernel_clockid_t value)
+{
+       switch (value) {
+       case CLOCK_REALTIME:
+       case CLOCK_MONOTONIC:
+       case CLOCK_TAI:
+               return 0;
+       }
+       return -EINVAL;
+}
+
 /*
  *     This is meant for all protocols to use and covers goings on
  *     at the socket level. Everything here is generic.
@@ -1497,6 +1508,11 @@ set_sndbuf:
                        ret = -EPERM;
                        break;
                }
+
+               ret = sockopt_validate_clockid(sk_txtime.clockid);
+               if (ret)
+                       break;
+
                sock_valbool_flag(sk, SOCK_TXTIME, true);
                sk->sk_clockid = sk_txtime.clockid;
                sk->sk_txtime_deadline_mode =