Author: kevlo
Date: Sun May 22 14:31:20 2016
New Revision: 300423
URL: https://svnweb.freebsd.org/changeset/base/300423
Log:
arc4random() returns 0 to (2**32)−1, use an alternative to initialize
i_gen if it's zero rather than a divide by 2.
With inputs from delphij, mckusick, rmacklem
Reviewed by: mckusick
Modified:
head/sys/fs/ext2fs/ext2_alloc.c
head/sys/fs/ext2fs/ext2_vfsops.c
head/sys/ufs/ffs/ffs_alloc.c
head/sys/ufs/ffs/ffs_vfsops.c
Modified: head/sys/fs/ext2fs/ext2_alloc.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_alloc.c Sun May 22 14:13:20 2016
(r300422)
+++ head/sys/fs/ext2fs/ext2_alloc.c Sun May 22 14:31:20 2016
(r300423)
@@ -408,7 +408,8 @@ ext2_valloc(struct vnode *pvp, int mode,
/*
* Set up a new generation number for this inode.
*/
- ip->i_gen = arc4random();
+ while (ip->i_gen == 0 || ++ip->i_gen == 0)
+ ip->i_gen = arc4random();
vfs_timestamp(&ts);
ip->i_birthtime = ts.tv_sec;
Modified: head/sys/fs/ext2fs/ext2_vfsops.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_vfsops.c Sun May 22 14:13:20 2016
(r300422)
+++ head/sys/fs/ext2fs/ext2_vfsops.c Sun May 22 14:31:20 2016
(r300423)
@@ -998,7 +998,8 @@ ext2_vget(struct mount *mp, ino_t ino, i
* already have one. This should only happen on old filesystems.
*/
if (ip->i_gen == 0) {
- ip->i_gen = random() + 1;
+ while (ip->i_gen == 0)
+ ip->i_gen = arc4random();
if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0)
ip->i_flag |= IN_MODIFIED;
}
Modified: head/sys/ufs/ffs/ffs_alloc.c
==============================================================================
--- head/sys/ufs/ffs/ffs_alloc.c Sun May 22 14:13:20 2016
(r300422)
+++ head/sys/ufs/ffs/ffs_alloc.c Sun May 22 14:31:20 2016
(r300423)
@@ -1102,8 +1102,8 @@ dup_alloc:
/*
* Set up a new generation number for this inode.
*/
- if (ip->i_gen == 0 || ++ip->i_gen == 0)
- ip->i_gen = arc4random() / 2 + 1;
+ while (ip->i_gen == 0 || ++ip->i_gen == 0)
+ ip->i_gen = arc4random();
DIP_SET(ip, i_gen, ip->i_gen);
if (fs->fs_magic == FS_UFS2_MAGIC) {
vfs_timestamp(&ts);
@@ -2080,7 +2080,8 @@ gotit:
bzero(ibp->b_data, (int)fs->fs_bsize);
dp2 = (struct ufs2_dinode *)(ibp->b_data);
for (i = 0; i < INOPB(fs); i++) {
- dp2->di_gen = arc4random() / 2 + 1;
+ while (dp2->di_gen == 0)
+ dp2->di_gen = arc4random();
dp2++;
}
/*
Modified: head/sys/ufs/ffs/ffs_vfsops.c
==============================================================================
--- head/sys/ufs/ffs/ffs_vfsops.c Sun May 22 14:13:20 2016
(r300422)
+++ head/sys/ufs/ffs/ffs_vfsops.c Sun May 22 14:31:20 2016
(r300423)
@@ -1768,7 +1768,8 @@ ffs_vgetf(mp, ino, flags, vpp, ffs_flags
* already have one. This should only happen on old filesystems.
*/
if (ip->i_gen == 0) {
- ip->i_gen = arc4random() / 2 + 1;
+ while (ip->i_gen == 0)
+ ip->i_gen = arc4random();
if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
ip->i_flag |= IN_MODIFIED;
DIP_SET(ip, i_gen, ip->i_gen);
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