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authorDavid Howells <dhowells@redhat.com>2017-12-01 14:40:43 +0300
committerDavid Howells <dhowells@redhat.com>2017-12-01 14:51:24 +0300
commitf8de483e7440b0d23ce6372b3ef8358841c8827b (patch)
tree7c1f01841c8171313af72a3f378393f916493032 /fs/afs
parent1bcab12521d9b23dbaa22ac71184778dcc43e2f6 (diff)
downloadlinux-f8de483e7440b0d23ce6372b3ef8358841c8827b.tar.xz
afs: Properly reset afs_vnode (inode) fields
When an AFS inode is allocated by afs_alloc_inode(), the allocated afs_vnode struct isn't necessarily reset from the last time it was used as an inode because the slab constructor is only invoked once when the memory is obtained from the page allocator. This means that information can leak from one inode to the next because we're not calling kmem_cache_zalloc(). Some of the information isn't reset, in particular the permit cache pointer. Bring the clearances up to date. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marc Dionne <marc.dionne@auristor.com>
Diffstat (limited to 'fs/afs')
-rw-r--r--fs/afs/internal.h5
-rw-r--r--fs/afs/super.c14
2 files changed, 17 insertions, 2 deletions
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index e03910cebdd4..804d1f905622 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -441,7 +441,10 @@ enum afs_lock_state {
};
/*
- * AFS inode private data
+ * AFS inode private data.
+ *
+ * Note that afs_alloc_inode() *must* reset anything that could incorrectly
+ * leak from one inode to another.
*/
struct afs_vnode {
struct inode vfs_inode; /* the VFS's inode record */
diff --git a/fs/afs/super.c b/fs/afs/super.c
index d3f97da61bdf..1037dd41a622 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -536,7 +536,9 @@ static void afs_kill_super(struct super_block *sb)
}
/*
- * initialise an inode cache slab element prior to any use
+ * Initialise an inode cache slab element prior to any use. Note that
+ * afs_alloc_inode() *must* reset anything that could incorrectly leak from one
+ * inode to another.
*/
static void afs_i_init_once(void *_vnode)
{
@@ -568,11 +570,21 @@ static struct inode *afs_alloc_inode(struct super_block *sb)
atomic_inc(&afs_count_active_inodes);
+ /* Reset anything that shouldn't leak from one inode to the next. */
memset(&vnode->fid, 0, sizeof(vnode->fid));
memset(&vnode->status, 0, sizeof(vnode->status));
vnode->volume = NULL;
+ vnode->lock_key = NULL;
+ vnode->permit_cache = NULL;
+ vnode->cb_interest = NULL;
+#ifdef CONFIG_AFS_FSCACHE
+ vnode->cache = NULL;
+#endif
+
vnode->flags = 1 << AFS_VNODE_UNSET;
+ vnode->cb_type = 0;
+ vnode->lock_state = AFS_VNODE_LOCK_NONE;
_leave(" = %p", &vnode->vfs_inode);
return &vnode->vfs_inode;