Module Name:    src
Committed By:   riastradh
Date:           Sat Apr 29 08:15:13 UTC 2023

Modified Files:
        src/sys/fs/tmpfs: tmpfs_subr.c

Log Message:
tmpfs: Assert no arithmetic overflow in directory node tn_size.

Need >2^57 directory entries before this is a problem.  If we created
a million per second, this would take over 4000 years.


To generate a diff of this commit:
cvs rdiff -u -r1.116 -r1.117 src/sys/fs/tmpfs/tmpfs_subr.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/fs/tmpfs/tmpfs_subr.c
diff -u src/sys/fs/tmpfs/tmpfs_subr.c:1.116 src/sys/fs/tmpfs/tmpfs_subr.c:1.117
--- src/sys/fs/tmpfs/tmpfs_subr.c:1.116	Sat Apr 29 08:13:27 2023
+++ src/sys/fs/tmpfs/tmpfs_subr.c	Sat Apr 29 08:15:13 2023
@@ -1,4 +1,4 @@
-/*	$NetBSD: tmpfs_subr.c,v 1.116 2023/04/29 08:13:27 riastradh Exp $	*/
+/*	$NetBSD: tmpfs_subr.c,v 1.117 2023/04/29 08:15:13 riastradh Exp $	*/
 
 /*
  * Copyright (c) 2005-2020 The NetBSD Foundation, Inc.
@@ -73,7 +73,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tmpfs_subr.c,v 1.116 2023/04/29 08:13:27 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tmpfs_subr.c,v 1.117 2023/04/29 08:15:13 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/cprng.h>
@@ -522,6 +522,7 @@ tmpfs_dir_attach(tmpfs_node_t *dnode, tm
 
 	/* Insert the entry to the directory (parent of inode). */
 	TAILQ_INSERT_TAIL(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries);
+	KASSERT(dnode->tn_size <= __type_max(off_t) - sizeof(tmpfs_dirent_t));
 	dnode->tn_size += sizeof(tmpfs_dirent_t);
 	uvm_vnp_setsize(dvp, dnode->tn_size);
 
@@ -580,6 +581,7 @@ tmpfs_dir_detach(tmpfs_node_t *dnode, tm
 		dnode->tn_spec.tn_dir.tn_readdir_lastp = NULL;
 	}
 	TAILQ_REMOVE(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries);
+	KASSERT(dnode->tn_size >= sizeof(tmpfs_dirent_t));
 	dnode->tn_size -= sizeof(tmpfs_dirent_t);
 	tmpfs_dir_putseq(dnode, de);
 

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