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authorMiklos Szeredi <mszeredi@redhat.com>2016-09-16 14:12:11 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2016-09-16 14:12:11 +0200
commit2b6bc7f48d34a6043915beddbf53b981603737c8 (patch)
treeab544e0b8c1c33dba94d79edeb0be310a51499ca /fs/overlayfs
parent8b326c61de08f5ca4bc454a168f19e7e43c4cc2a (diff)
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ovl: lookup: do getxattr with mounter's permission
The getxattr() in ovl_is_opaquedir() was missed when converting all operations on underlying fs to be done under mounter's permission. This patch fixes this by moving the ovl_override_creds()/revert_creds() out from ovl_lookup_real() to ovl_lookup(). Also convert to using vfs_getxattr() instead of directly calling i_op->getxattr(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/super.c20
1 files changed, 9 insertions, 11 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index e2a94a26767b..8ccebaf64c5b 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -273,12 +273,11 @@ static bool ovl_is_opaquedir(struct dentry *dentry)
{
int res;
char val;
- struct inode *inode = dentry->d_inode;
- if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr)
+ if (!d_is_dir(dentry))
return false;
- res = inode->i_op->getxattr(dentry, inode, OVL_XATTR_OPAQUE, &val, 1);
+ res = vfs_getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1);
if (res == 1 && val == 'y')
return true;
@@ -419,16 +418,12 @@ static bool ovl_dentry_weird(struct dentry *dentry)
DCACHE_OP_COMPARE);
}
-static inline struct dentry *ovl_lookup_real(struct super_block *ovl_sb,
- struct dentry *dir,
+static inline struct dentry *ovl_lookup_real(struct dentry *dir,
const struct qstr *name)
{
- const struct cred *old_cred;
struct dentry *dentry;
- old_cred = ovl_override_creds(ovl_sb);
dentry = lookup_one_len_unlocked(name->name, dir, name->len);
- revert_creds(old_cred);
if (IS_ERR(dentry)) {
if (PTR_ERR(dentry) == -ENOENT)
@@ -469,6 +464,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct ovl_entry *oe;
+ const struct cred *old_cred;
struct ovl_entry *poe = dentry->d_parent->d_fsdata;
struct path *stack = NULL;
struct dentry *upperdir, *upperdentry = NULL;
@@ -479,9 +475,10 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int i;
int err;
+ old_cred = ovl_override_creds(dentry->d_sb);
upperdir = ovl_upperdentry_dereference(poe);
if (upperdir) {
- this = ovl_lookup_real(dentry->d_sb, upperdir, &dentry->d_name);
+ this = ovl_lookup_real(upperdir, &dentry->d_name);
err = PTR_ERR(this);
if (IS_ERR(this))
goto out;
@@ -514,8 +511,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
bool opaque = false;
struct path lowerpath = poe->lowerstack[i];
- this = ovl_lookup_real(dentry->d_sb,
- lowerpath.dentry, &dentry->d_name);
+ this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name);
err = PTR_ERR(this);
if (IS_ERR(this)) {
/*
@@ -588,6 +584,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
ovl_copyattr(realdentry->d_inode, inode);
}
+ revert_creds(old_cred);
oe->opaque = upperopaque;
oe->__upperdentry = upperdentry;
memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
@@ -606,6 +603,7 @@ out_put:
out_put_upper:
dput(upperdentry);
out:
+ revert_creds(old_cred);
return ERR_PTR(err);
}