Revision 9dfef3adaebb42163d691be73e05b12da440cbe5 authored by Yuval Mintz on 05 January 2014, 16:33:53 UTC, committed by David S. Miller on 06 January 2014, 01:22:25 UTC
There are 2 different (related) flows in the slowpath configuration that utilize the same pointer and cast it to different structs; This is obviously incorrect as the intended allocated memory is that of the smaller struct, possibly causing the flow utilizing the larger struct to corrupt other slowpath configuration. Since both flows are exclusive, set the allocated memory to be a union of both structs. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com> Signed-off-by: Ariel Elior <ariele@broadcom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 5b62291
anon_inodes.c
/*
* fs/anon_inodes.c
*
* Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org>
*
* Thanks to Arnd Bergmann for code review and suggestions.
* More changes for Thomas Gleixner suggestions.
*
*/
#include <linux/cred.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/magic.h>
#include <linux/anon_inodes.h>
#include <asm/uaccess.h>
static struct vfsmount *anon_inode_mnt __read_mostly;
static struct inode *anon_inode_inode;
/*
* anon_inodefs_dname() is called from d_path().
*/
static char *anon_inodefs_dname(struct dentry *dentry, char *buffer, int buflen)
{
return dynamic_dname(dentry, buffer, buflen, "anon_inode:%s",
dentry->d_name.name);
}
static const struct dentry_operations anon_inodefs_dentry_operations = {
.d_dname = anon_inodefs_dname,
};
static struct dentry *anon_inodefs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
struct dentry *root;
root = mount_pseudo(fs_type, "anon_inode:", NULL,
&anon_inodefs_dentry_operations, ANON_INODE_FS_MAGIC);
if (!IS_ERR(root)) {
struct super_block *s = root->d_sb;
anon_inode_inode = alloc_anon_inode(s);
if (IS_ERR(anon_inode_inode)) {
dput(root);
deactivate_locked_super(s);
root = ERR_CAST(anon_inode_inode);
}
}
return root;
}
static struct file_system_type anon_inode_fs_type = {
.name = "anon_inodefs",
.mount = anon_inodefs_mount,
.kill_sb = kill_anon_super,
};
/**
* anon_inode_getfile - creates a new file instance by hooking it up to an
* anonymous inode, and a dentry that describe the "class"
* of the file
*
* @name: [in] name of the "class" of the new file
* @fops: [in] file operations for the new file
* @priv: [in] private data for the new file (will be file's private_data)
* @flags: [in] flags
*
* Creates a new file by hooking it on a single inode. This is useful for files
* that do not need to have a full-fledged inode in order to operate correctly.
* All the files created with anon_inode_getfile() will share a single inode,
* hence saving memory and avoiding code duplication for the file/inode/dentry
* setup. Returns the newly created file* or an error pointer.
*/
struct file *anon_inode_getfile(const char *name,
const struct file_operations *fops,
void *priv, int flags)
{
struct qstr this;
struct path path;
struct file *file;
if (IS_ERR(anon_inode_inode))
return ERR_PTR(-ENODEV);
if (fops->owner && !try_module_get(fops->owner))
return ERR_PTR(-ENOENT);
/*
* Link the inode to a directory entry by creating a unique name
* using the inode sequence number.
*/
file = ERR_PTR(-ENOMEM);
this.name = name;
this.len = strlen(name);
this.hash = 0;
path.dentry = d_alloc_pseudo(anon_inode_mnt->mnt_sb, &this);
if (!path.dentry)
goto err_module;
path.mnt = mntget(anon_inode_mnt);
/*
* We know the anon_inode inode count is always greater than zero,
* so ihold() is safe.
*/
ihold(anon_inode_inode);
d_instantiate(path.dentry, anon_inode_inode);
file = alloc_file(&path, OPEN_FMODE(flags), fops);
if (IS_ERR(file))
goto err_dput;
file->f_mapping = anon_inode_inode->i_mapping;
file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);
file->private_data = priv;
return file;
err_dput:
path_put(&path);
err_module:
module_put(fops->owner);
return file;
}
EXPORT_SYMBOL_GPL(anon_inode_getfile);
/**
* anon_inode_getfd - creates a new file instance by hooking it up to an
* anonymous inode, and a dentry that describe the "class"
* of the file
*
* @name: [in] name of the "class" of the new file
* @fops: [in] file operations for the new file
* @priv: [in] private data for the new file (will be file's private_data)
* @flags: [in] flags
*
* Creates a new file by hooking it on a single inode. This is useful for files
* that do not need to have a full-fledged inode in order to operate correctly.
* All the files created with anon_inode_getfd() will share a single inode,
* hence saving memory and avoiding code duplication for the file/inode/dentry
* setup. Returns new descriptor or an error code.
*/
int anon_inode_getfd(const char *name, const struct file_operations *fops,
void *priv, int flags)
{
int error, fd;
struct file *file;
error = get_unused_fd_flags(flags);
if (error < 0)
return error;
fd = error;
file = anon_inode_getfile(name, fops, priv, flags);
if (IS_ERR(file)) {
error = PTR_ERR(file);
goto err_put_unused_fd;
}
fd_install(fd, file);
return fd;
err_put_unused_fd:
put_unused_fd(fd);
return error;
}
EXPORT_SYMBOL_GPL(anon_inode_getfd);
static int __init anon_inode_init(void)
{
int error;
error = register_filesystem(&anon_inode_fs_type);
if (error)
goto err_exit;
anon_inode_mnt = kern_mount(&anon_inode_fs_type);
if (IS_ERR(anon_inode_mnt)) {
error = PTR_ERR(anon_inode_mnt);
goto err_unregister_filesystem;
}
return 0;
err_unregister_filesystem:
unregister_filesystem(&anon_inode_fs_type);
err_exit:
panic(KERN_ERR "anon_inode_init() failed (%d)\n", error);
}
fs_initcall(anon_inode_init);
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