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Commit 78833dd7 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  nd->inode is not set on the second attempt in path_walk()
  unfuck proc_sysctl ->d_compare()
  minimal fix for do_filp_open() race
parents a5abba98 b306419a

fs/namei.c

+11 −3
Original line number Diff line number Diff line
@@ -1546,6 +1546,7 @@ static int path_walk(const char *name, struct nameidata *nd) 
		/* nd->path had been dropped */

		current->total_link_count = 0;

		nd->path = save;

		nd->inode = save.dentry->d_inode;

		path_get(&nd->path);

		nd->flags |= LOOKUP_REVAL;

		result = link_path_walk(name, nd);
@@ -2455,22 +2456,29 @@ struct file *do_filp_open(int dfd, const char *pathname, 
	/* !O_CREAT, simple open */

	error = do_path_lookup(dfd, pathname, flags, &nd);

	if (unlikely(error))

		goto out_filp;

		goto out_filp2;

	error = -ELOOP;

	if (!(nd.flags & LOOKUP_FOLLOW)) {

		if (nd.inode->i_op->follow_link)

			goto out_path;

			goto out_path2;

	}

	error = -ENOTDIR;

	if (nd.flags & LOOKUP_DIRECTORY) {

		if (!nd.inode->i_op->lookup)

			goto out_path;

			goto out_path2;

	}

	audit_inode(pathname, nd.path.dentry);

	filp = finish_open(&nd, open_flag, acc_mode);

out2:

	release_open_intent(&nd);

	return filp;



out_path2:

	path_put(&nd.path);

out_filp2:

	filp = ERR_PTR(error);

	goto out2;



creat:

	/* OK, have to create the file. Find the parent. */

	error = path_init_rcu(dfd, pathname,

fs/proc/inode.c

+6 −2
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
static void proc_evict_inode(struct inode *inode)

{

	struct proc_dir_entry *de;

	struct ctl_table_header *head;



	truncate_inode_pages(&inode->i_data, 0);

	end_writeback(inode);
@@ -38,8 +39,11 @@ static void proc_evict_inode(struct inode *inode) 
	de = PROC_I(inode)->pde;

	if (de)

		pde_put(de);

	if (PROC_I(inode)->sysctl)

		sysctl_head_put(PROC_I(inode)->sysctl);

	head = PROC_I(inode)->sysctl;

	if (head) {

		rcu_assign_pointer(PROC_I(inode)->sysctl, NULL);

		sysctl_head_put(head);

	}

}



struct vfsmount *proc_mnt;

fs/proc/proc_sysctl.c

+5 −2
Original line number Diff line number Diff line
@@ -408,15 +408,18 @@ static int proc_sys_compare(const struct dentry *parent, 
		const struct dentry *dentry, const struct inode *inode,

		unsigned int len, const char *str, const struct qstr *name)

{

	struct ctl_table_header *head;

	/* Although proc doesn't have negative dentries, rcu-walk means

	 * that inode here can be NULL */

	/* AV: can it, indeed? */

	if (!inode)

		return 0;

		return 1;

	if (name->len != len)

		return 1;

	if (memcmp(name->name, str, len))

		return 1;

	return !sysctl_is_seen(PROC_I(inode)->sysctl);

	head = rcu_dereference(PROC_I(inode)->sysctl);

	return !head || !sysctl_is_seen(head);

}



static const struct dentry_operations proc_sys_dentry_operations = {

include/linux/sysctl.h

+10 −4
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/kernel.h>

#include <linux/types.h>

#include <linux/compiler.h>

#include <linux/rcupdate.h>



struct completion;
@@ -1037,10 +1038,15 @@ struct ctl_table_root { 
   struct ctl_table trees. */

struct ctl_table_header

{

	union {

		struct {

			struct ctl_table *ctl_table;

			struct list_head ctl_entry;

			int used;

			int count;

		};

		struct rcu_head rcu;

	};

	struct completion *unregistering;

	struct ctl_table *ctl_table_arg;

	struct ctl_table_root *root;

kernel/sysctl.c

+10 −5
Original line number Diff line number Diff line
@@ -194,9 +194,9 @@ static int sysrq_sysctl_handler(ctl_table *table, int write, 
static struct ctl_table root_table[];

static struct ctl_table_root sysctl_table_root;

static struct ctl_table_header root_table_header = {

	.count = 1,

	{{.count = 1,

	.ctl_table = root_table,

	.ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),

	.ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},

	.root = &sysctl_table_root,

	.set = &sysctl_table_root.default_set,

};
@@ -1567,11 +1567,16 @@ void sysctl_head_get(struct ctl_table_header *head) 
	spin_unlock(&sysctl_lock);

}



static void free_head(struct rcu_head *rcu)

{

	kfree(container_of(rcu, struct ctl_table_header, rcu));

}



void sysctl_head_put(struct ctl_table_header *head)

{

	spin_lock(&sysctl_lock);

	if (!--head->count)

		kfree(head);

		call_rcu(&head->rcu, free_head);

	spin_unlock(&sysctl_lock);

}
@@ -1948,10 +1953,10 @@ void unregister_sysctl_table(struct ctl_table_header * header) 
	start_unregistering(header);

	if (!--header->parent->count) {

		WARN_ON(1);

		kfree(header->parent);

		call_rcu(&header->parent->rcu, free_head);

	}

	if (!--header->count)

		kfree(header);

		call_rcu(&header->rcu, free_head);

	spin_unlock(&sysctl_lock);

}