| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Wed, 9 Jan 2008 21:16:31 -0500
From: Erez Zadok <ezk@...sunysb.edu>
To: akpm@...ux-foundation.org
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
viro@....linux.org.uk, hch@...radead.org,
Erez Zadok <ezk@...sunysb.edu>
Subject: [PATCH 3/4] Unionfs: branch-management related locking fixes
Add necessary locking to dentry/inode branch-configuration, so we get
consistent values during branch-management actions. In d_revalidate_chain,
->permission, and ->create, also lock parent dentry.
Signed-off-by: Erez Zadok <ezk@...sunysb.edu>
---
fs/unionfs/commonfops.c | 6 ++++++
fs/unionfs/dentry.c | 6 +++++-
fs/unionfs/inode.c | 17 +++++++++++++++++
3 files changed, 28 insertions(+), 1 deletions(-)
diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
index 2c32ada..f37192f 100644
--- a/fs/unionfs/commonfops.c
+++ b/fs/unionfs/commonfops.c
@@ -318,6 +318,7 @@ int unionfs_file_revalidate(struct file *file, bool willwrite)
* First revalidate the dentry inside struct file,
* but not unhashed dentries.
*/
+reval_dentry:
if (unlikely(!d_deleted(dentry) &&
!__unionfs_d_revalidate_chain(dentry, NULL, willwrite))) {
err = -ESTALE;
@@ -328,6 +329,11 @@ int unionfs_file_revalidate(struct file *file, bool willwrite)
dgen = atomic_read(&UNIONFS_D(dentry)->generation);
fgen = atomic_read(&UNIONFS_F(file)->generation);
+ if (unlikely(sbgen > dgen)) {
+ pr_debug("unionfs: retry dentry revalidation\n");
+ schedule();
+ goto reval_dentry;
+ }
BUG_ON(sbgen > dgen);
/*
diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c
index 7646828..d969640 100644
--- a/fs/unionfs/dentry.c
+++ b/fs/unionfs/dentry.c
@@ -203,7 +203,7 @@ bool is_newer_lower(const struct dentry *dentry)
if (!dentry || !UNIONFS_D(dentry))
return false;
inode = dentry->d_inode;
- if (!inode || !UNIONFS_I(inode) ||
+ if (!inode || !UNIONFS_I(inode)->lower_inodes ||
ibstart(inode) < 0 || ibend(inode) < 0)
return false;
@@ -295,6 +295,8 @@ bool __unionfs_d_revalidate_chain(struct dentry *dentry, struct nameidata *nd,
chain_len = 0;
sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation);
dtmp = dentry->d_parent;
+ if (dentry != dtmp)
+ unionfs_lock_dentry(dtmp, UNIONFS_DMUTEX_REVAL_PARENT);
dgen = atomic_read(&UNIONFS_D(dtmp)->generation);
/* XXX: should we check if is_newer_lower all the way up? */
if (unlikely(is_newer_lower(dtmp))) {
@@ -315,6 +317,8 @@ bool __unionfs_d_revalidate_chain(struct dentry *dentry, struct nameidata *nd,
}
purge_inode_data(dtmp->d_inode);
}
+ if (dentry != dtmp)
+ unionfs_unlock_dentry(dtmp);
while (sbgen != dgen) {
/* The root entry should always be valid */
BUG_ON(IS_ROOT(dtmp));
diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c
index 6095c4f..e15ddb9 100644
--- a/fs/unionfs/inode.c
+++ b/fs/unionfs/inode.c
@@ -30,6 +30,13 @@ static int unionfs_create(struct inode *parent, struct dentry *dentry,
struct nameidata lower_nd;
unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
+ unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT);
+ valid = __unionfs_d_revalidate_chain(dentry->d_parent, nd, false);
+ unionfs_unlock_dentry(dentry->d_parent);
+ if (unlikely(!valid)) {
+ err = -ESTALE; /* same as what real_lookup does */
+ goto out;
+ }
unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
valid = __unionfs_d_revalidate_chain(dentry, nd, false);
@@ -936,6 +943,14 @@ static int unionfs_permission(struct inode *inode, int mask,
const int is_file = !S_ISDIR(inode->i_mode);
const int write_mask = (mask & MAY_WRITE) && !(mask & MAY_READ);
+ if (nd)
+ unionfs_lock_dentry(nd->dentry, UNIONFS_DMUTEX_CHILD);
+
+ if (!UNIONFS_I(inode)->lower_inodes) {
+ if (is_file) /* dirs can be unlinked but chdir'ed to */
+ err = -ESTALE; /* force revalidate */
+ goto out;
+ }
bstart = ibstart(inode);
bend = ibend(inode);
if (unlikely(bstart < 0 || bend < 0)) {
@@ -1003,6 +1018,8 @@ static int unionfs_permission(struct inode *inode, int mask,
out:
unionfs_check_inode(inode);
unionfs_check_nd(nd);
+ if (nd)
+ unionfs_unlock_dentry(nd->dentry);
return err;
}
--
1.5.2.2
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists