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bpf: reject invalid names right in ->lookup() 

... and other methods won't see them at all

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-03-25 12:06:51 -04:00
parent 798434bda3
commit 0c93b7d85d
1 changed files with 8 additions and 29 deletions
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37
kernel/bpf/inode.c
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@ -119,18 +119,10 @@ static int bpf_inode_type(const struct inode *inode, enum bpf_type *type)
return 0; return 0;
} }
static bool bpf_dname_reserved(const struct dentry *dentry)
{
return strchr(dentry->d_name.name, '.');
}
static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{ {
struct inode *inode; struct inode *inode;
if (bpf_dname_reserved(dentry))
return -EPERM;
inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR); inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR);
if (IS_ERR(inode)) if (IS_ERR(inode))
return PTR_ERR(inode); return PTR_ERR(inode);
@ -152,9 +144,6 @@ static int bpf_mkobj_ops(struct inode *dir, struct dentry *dentry,
{ {
struct inode *inode; struct inode *inode;
if (bpf_dname_reserved(dentry))
return -EPERM;
inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFREG); inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFREG);
if (IS_ERR(inode)) if (IS_ERR(inode))
return PTR_ERR(inode); return PTR_ERR(inode);
@ -187,31 +176,21 @@ static int bpf_mkobj(struct inode *dir, struct dentry *dentry, umode_t mode,
} }
} }
static int bpf_link(struct dentry *old_dentry, struct inode *dir, static struct dentry *
struct dentry *new_dentry) bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags)
{ {
if (bpf_dname_reserved(new_dentry)) if (strchr(dentry->d_name.name, '.'))
return -EPERM; return ERR_PTR(-EPERM);
return simple_lookup(dir, dentry, flags);
return simple_link(old_dentry, dir, new_dentry);
}
static int bpf_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
if (bpf_dname_reserved(new_dentry))
return -EPERM;
return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
} }
static const struct inode_operations bpf_dir_iops = { static const struct inode_operations bpf_dir_iops = {
.lookup = simple_lookup, .lookup = bpf_lookup,
.mknod = bpf_mkobj, .mknod = bpf_mkobj,
.mkdir = bpf_mkdir, .mkdir = bpf_mkdir,
.rmdir = simple_rmdir, .rmdir = simple_rmdir,
.rename = bpf_rename, .rename = simple_rename,
.link = bpf_link, .link = simple_link,
.unlink = simple_unlink, .unlink = simple_unlink,
}; };