linux-kernel - [PATCH 3.18.y 3/5] security_d_instantiate(): move to the point prior to attaching dentry to inode

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Date:   Thu,  9 Aug 2018 18:53:42 +0900
From:   Seung-Woo Kim <sw0312.kim@...sung.com>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        gregkh@...uxfoundation.org
Cc:     viro@...iv.linux.org.uk, akpm@...ux-foundation.org,
        torvalds@...ux-foundation.org, jslaby@...e.cz,
        sw0312.kim@...sung.com
Subject: [PATCH 3.18.y 3/5] security_d_instantiate(): move to the point
 prior to attaching dentry to inode

From: Al Viro <viro@...iv.linux.org.uk>

commit b96809173e94ea2fa8c19c2e40e8545a1821bf57 upstream.

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>

[sw0312.kim: backport to 3.18]
Signed-off-by: Seung-Woo Kim <sw0312.kim@...sung.com>
---
 fs/dcache.c |   18 +++++++-----------
 1 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index a34d401..6a4290a 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1729,12 +1729,12 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode)
 void d_instantiate(struct dentry *entry, struct inode * inode)
 {
 	BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
+	security_d_instantiate(entry, inode);
 	if (inode)
 		spin_lock(&inode->i_lock);
 	__d_instantiate(entry, inode);
 	if (inode)
 		spin_unlock(&inode->i_lock);
-	security_d_instantiate(entry, inode);
 }
 EXPORT_SYMBOL(d_instantiate);
 
@@ -1795,16 +1795,15 @@ struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
 
 	BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
 
+	security_d_instantiate(entry, inode);
 	if (inode)
 		spin_lock(&inode->i_lock);
 	result = __d_instantiate_unique(entry, inode);
 	if (inode)
 		spin_unlock(&inode->i_lock);
 
-	if (!result) {
-		security_d_instantiate(entry, inode);
+	if (!result)
 		return NULL;
-	}
 
 	BUG_ON(!d_unhashed(result));
 	iput(inode);
@@ -1826,6 +1825,7 @@ int d_instantiate_no_diralias(struct dentry *entry, struct inode *inode)
 {
 	BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
 
+	security_d_instantiate(entry, inode);
 	spin_lock(&inode->i_lock);
 	if (S_ISDIR(inode->i_mode) && !hlist_empty(&inode->i_dentry)) {
 		spin_unlock(&inode->i_lock);
@@ -1834,7 +1834,6 @@ int d_instantiate_no_diralias(struct dentry *entry, struct inode *inode)
 	}
 	__d_instantiate(entry, inode);
 	spin_unlock(&inode->i_lock);
-	security_d_instantiate(entry, inode);
 
 	return 0;
 }
@@ -1930,6 +1929,7 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
 		goto out_iput;
 	}
 
+	security_d_instantiate(tmp, inode);
 	spin_lock(&inode->i_lock);
 	res = __d_find_any_alias(inode);
 	if (res) {
@@ -1953,13 +1953,10 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
 	hlist_bl_unlock(&tmp->d_sb->s_anon);
 	spin_unlock(&tmp->d_lock);
 	spin_unlock(&inode->i_lock);
-	security_d_instantiate(tmp, inode);
 
 	return tmp;
 
  out_iput:
-	if (res && !IS_ERR(res))
-		security_d_instantiate(res, inode);
 	iput(inode);
 	return res;
 }
@@ -2817,6 +2814,7 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
 		return ERR_CAST(inode);
 
 	if (inode && S_ISDIR(inode->i_mode)) {
+		security_d_instantiate(dentry, inode);
 		spin_lock(&inode->i_lock);
 		new = __d_find_any_alias(inode);
 		if (new) {
@@ -2836,13 +2834,11 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
 			__d_move(new, dentry, false);
 			write_sequnlock(&rename_lock);
 			spin_unlock(&inode->i_lock);
-			security_d_instantiate(new, inode);
 			iput(inode);
 		} else {
 			/* already taking inode->i_lock, so d_add() by hand */
 			__d_instantiate(dentry, inode);
 			spin_unlock(&inode->i_lock);
-			security_d_instantiate(dentry, inode);
 			d_rehash(dentry);
 		}
 	} else {
@@ -2876,6 +2872,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
 		goto out_nolock;
 	}
 
+	security_d_instantiate(dentry, inode);
 	spin_lock(&inode->i_lock);
 
 	if (S_ISDIR(inode->i_mode)) {
@@ -2927,7 +2924,6 @@ found:
 	spin_unlock(&inode->i_lock);
 out_nolock:
 	if (actual == dentry) {
-		security_d_instantiate(dentry, inode);
 		return NULL;
 	}
 
-- 
1.7.4.1