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alistair23-linux/fs/9p/fid.c
Kees Cook 6da2ec5605 treewide: kmalloc() -> kmalloc_array() 
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This
patch replaces cases of:

        kmalloc(a * b, gfp)

with:
        kmalloc_array(a * b, gfp)

as well as handling cases of:

        kmalloc(a * b * c, gfp)

with:

        kmalloc(array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        kmalloc_array(array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        kmalloc(4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The tools/ directory was manually excluded, since it has its own
implementation of kmalloc().

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  kmalloc(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  kmalloc(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  kmalloc(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kmalloc
+ kmalloc_array
  (
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  kmalloc(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  kmalloc(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  kmalloc(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  kmalloc(sizeof(THING) * C2, ...)
|
  kmalloc(sizeof(TYPE) * C2, ...)
|
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(C1 * C2, ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * E2
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	E1 * E2
+	E1, E2
  , ...)
)

Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-12 16:19:22 -07:00

283 lines
6.8 KiB
C
Raw Blame History

/*
* V9FS FID Management
*
* Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
* Copyright (C) 2005, 2006 by Eric Van Hensbergen <ericvh@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/idr.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
/**
* v9fs_fid_add - add a fid to a dentry
* @dentry: dentry that the fid is being added to
* @fid: fid to add
*
*/
static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
{
hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
}
void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
{
spin_lock(&dentry->d_lock);
__add_fid(dentry, fid);
spin_unlock(&dentry->d_lock);
}
/**
* v9fs_fid_find - retrieve a fid that belongs to the specified uid
* @dentry: dentry to look for fid in
* @uid: return fid that belongs to the specified user
* @any: if non-zero, return any fid associated with the dentry
*
*/
static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
{
struct p9_fid *fid, *ret;
p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p) uid %d any %d\n",
dentry, dentry, from_kuid(&init_user_ns, uid),
any);
ret = NULL;
/* we'll recheck under lock if there's anything to look in */
if (dentry->d_fsdata) {
struct hlist_head *h = (struct hlist_head *)&dentry->d_fsdata;
spin_lock(&dentry->d_lock);
hlist_for_each_entry(fid, h, dlist) {
if (any || uid_eq(fid->uid, uid)) {
ret = fid;
break;
}
}
spin_unlock(&dentry->d_lock);
}
return ret;
}
/*
* We need to hold v9ses->rename_sem as long as we hold references
* to returned path array. Array element contain pointers to
* dentry names.
*/
static int build_path_from_dentry(struct v9fs_session_info *v9ses,
struct dentry *dentry, const unsigned char ***names)
{
int n = 0, i;
const unsigned char **wnames;
struct dentry *ds;
for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
n++;
wnames = kmalloc_array(n, sizeof(char *), GFP_KERNEL);
if (!wnames)
goto err_out;
for (ds = dentry, i = (n-1); i >= 0; i--, ds = ds->d_parent)
wnames[i] = ds->d_name.name;
*names = wnames;
return n;
err_out:
return -ENOMEM;
}
static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
kuid_t uid, int any)
{
struct dentry *ds;
const unsigned char **wnames, *uname;
int i, n, l, clone, access;
struct v9fs_session_info *v9ses;
struct p9_fid *fid, *old_fid = NULL;
v9ses = v9fs_dentry2v9ses(dentry);
access = v9ses->flags & V9FS_ACCESS_MASK;
fid = v9fs_fid_find(dentry, uid, any);
if (fid)
return fid;
/*
* we don't have a matching fid. To do a TWALK we need
* parent fid. We need to prevent rename when we want to
* look at the parent.
*/
down_read(&v9ses->rename_sem);
ds = dentry->d_parent;
fid = v9fs_fid_find(ds, uid, any);
if (fid) {
/* Found the parent fid do a lookup with that */
fid = p9_client_walk(fid, 1, &dentry->d_name.name, 1);
goto fid_out;
}
up_read(&v9ses->rename_sem);
/* start from the root and try to do a lookup */
fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
if (!fid) {
/* the user is not attached to the fs yet */
if (access == V9FS_ACCESS_SINGLE)
return ERR_PTR(-EPERM);
if (v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses))
uname = NULL;
else
uname = v9ses->uname;
fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
v9ses->aname);
if (IS_ERR(fid))
return fid;
v9fs_fid_add(dentry->d_sb->s_root, fid);
}
/* If we are root ourself just return that */
if (dentry->d_sb->s_root == dentry)
return fid;
/*
* Do a multipath walk with attached root.
* When walking parent we need to make sure we
* don't have a parallel rename happening
*/
down_read(&v9ses->rename_sem);
n = build_path_from_dentry(v9ses, dentry, &wnames);
if (n < 0) {
fid = ERR_PTR(n);
goto err_out;
}
clone = 1;
i = 0;
while (i < n) {
l = min(n - i, P9_MAXWELEM);
/*
* We need to hold rename lock when doing a multipath
* walk to ensure none of the patch component change
*/
fid = p9_client_walk(fid, l, &wnames[i], clone);
if (IS_ERR(fid)) {
if (old_fid) {
/*
* If we fail, clunk fid which are mapping
* to path component and not the last component
* of the path.
*/
p9_client_clunk(old_fid);
}
kfree(wnames);
goto err_out;
}
old_fid = fid;
i += l;
clone = 0;
}
kfree(wnames);
fid_out:
if (!IS_ERR(fid)) {
spin_lock(&dentry->d_lock);
if (d_unhashed(dentry)) {
spin_unlock(&dentry->d_lock);
p9_client_clunk(fid);
fid = ERR_PTR(-ENOENT);
} else {
__add_fid(dentry, fid);
spin_unlock(&dentry->d_lock);
}
}
err_out:
up_read(&v9ses->rename_sem);
return fid;
}
/**
* v9fs_fid_lookup - lookup for a fid, try to walk if not found
* @dentry: dentry to look for fid in
*
* Look for a fid in the specified dentry for the current user.
* If no fid is found, try to create one walking from a fid from the parent
* dentry (if it has one), or the root dentry. If the user haven't accessed
* the fs yet, attach now and walk from the root.
*/
struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
{
kuid_t uid;
int any, access;
struct v9fs_session_info *v9ses;
v9ses = v9fs_dentry2v9ses(dentry);
access = v9ses->flags & V9FS_ACCESS_MASK;
switch (access) {
case V9FS_ACCESS_SINGLE:
case V9FS_ACCESS_USER:
case V9FS_ACCESS_CLIENT:
uid = current_fsuid();
any = 0;
break;
case V9FS_ACCESS_ANY:
uid = v9ses->uid;
any = 1;
break;
default:
uid = INVALID_UID;
any = 0;
break;
}
return v9fs_fid_lookup_with_uid(dentry, uid, any);
}
struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
{
int err;
struct p9_fid *fid;
fid = clone_fid(v9fs_fid_lookup_with_uid(dentry, GLOBAL_ROOT_UID, 0));
if (IS_ERR(fid))
goto error_out;
/*
* writeback fid will only be used to write back the
* dirty pages. We always request for the open fid in read-write
* mode so that a partial page write which result in page
* read can work.
*/
err = p9_client_open(fid, O_RDWR);
if (err < 0) {
p9_client_clunk(fid);
fid = ERR_PTR(err);
goto error_out;
}
error_out:
return fid;
}
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