ffs: Correct the input size check in sysctl_ffs_fsck()

Make sure we return an error if no input was specified, since
SYSCTL_IN() will report success in that case.

Reported by:	KMSAN
Reviewed by:	mckusick
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D30586

diff --git a/sys/ufs/ffs/ffs_alloc.c b/sys/ufs/ffs/ffs_alloc.c
index c7a1e2dec15e07127d718fd704f77f135586b69e..c895c8c7bf07714f1dd9fb2dcfc6b9e04e1c61b3 100644 (file)
--- a/sys/ufs/ffs/ffs_alloc.c
+++ b/sys/ufs/ffs/ffs_alloc.c
@@ -3211,9 +3211,9 @@ sysctl_ffs_fsck(SYSCTL_HANDLER_ARGS)
        cap_rights_t rights;
        int filetype, error;
 
-       if (req->newlen > sizeof cmd)
+       if (req->newptr == NULL || req->newlen > sizeof(cmd))
                return (EBADRPC);
-       if ((error = SYSCTL_IN(req, &cmd, sizeof cmd)) != 0)
+       if ((error = SYSCTL_IN(req, &cmd, sizeof(cmd))) != 0)
                return (error);
        if (cmd.version != FFS_CMD_VERSION)
                return (ERPCMISMATCH);