Continuing efforts to provide hardening of FFS. This change adds a

check hash to the filesystem inodes. Access attempts to files
associated with an inode with an invalid check hash will fail with
EINVAL (Invalid argument). Access is reestablished after an fsck
is run to find and validate the inodes with invalid check-hashes.
This check avoids a class of filesystem panics related to corrupted
inodes. The hash is done using crc32c.

Note this check-hash is for the inode itself and not any of its
indirect blocks. Check-hash validation may be extended to also
cover indirect block pointers, but that will be a separate (and
more costly) feature.

Check hashes are added only to UFS2 and not to UFS1 as UFS1 is
primarily used in embedded systems with small memories and low-powered
processors which need as light-weight a filesystem as possible.

Reviewed by:  kib
Tested by:    Peter Holm
Sponsored by: Netflix

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/sys/param.h b/sys/sys/param.h
index 64aa65bef7b0..a28bc884d25c 100644
--- a/sys/sys/param.h
+++ b/sys/sys/param.h
@@ -60,7 +60,7 @@
  *		in the range 5 to 9.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1300004	/* Master, propagated to newvers */
+#define __FreeBSD_version 1300005	/* Master, propagated to newvers */
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
@@ -89,6 +89,7 @@
 #define	P_OSREL_CK_CYLGRP		1200046
 #define	P_OSREL_VMTOTAL64		1200054
 #define	P_OSREL_CK_SUPERBLOCK		1300000
+#define	P_OSREL_CK_INODE		1300005
 
 #define	P_OSREL_MAJOR(x)		((x) / 100000)
 #endif