[PATCH 24/29] xfs: lift cursor copy in/out into xfs_ioc_attr_list

Christoph Hellwig
2020-01-14T08:16:27Z

Lift the common code to copy the cursor from and to user space into
xfs_ioc_attr_list. Note that this means we copy in twice now as
the cursor is in the middle of the conaining structure, but we never
touch the memory for the original copy. Doing so keeps the cursor
handling isolated in the common helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_ioctl.c | 36 +++++++++++++++---------------------
fs/xfs/xfs_ioctl.h | 2 +-
fs/xfs/xfs_ioctl32.c | 19 ++++---------------
3 files changed, 20 insertions(+), 37 deletions(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 8d7b8ad21d9e..899a3b41fa91 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -356,9 +356,10 @@ xfs_ioc_attr_list(
void __user *ubuf,
int bufsize,
int flags,
- struct attrlist_cursor_kern *cursor)
+ struct xfs_attrlist_cursor __user *ucursor)
{
struct xfs_attr_list_context context;
+ struct attrlist_cursor_kern cursor;
struct xfs_attrlist *alist;
void *buffer;
int error;
@@ -376,10 +377,12 @@ xfs_ioc_attr_list(
/*
* Validate the cursor.
*/
- if (cursor->pad1 || cursor->pad2)
+ if (copy_from_user(&cursor, ucursor, sizeof(cursor)))
+ return -EFAULT;
+ if (cursor.pad1 || cursor.pad2)
return -EINVAL;
- if ((cursor->initted == 0) &&
- (cursor->hashval || cursor->blkno || cursor->offset))
+ if ((cursor.initted == 0) &&
+ (cursor.hashval || cursor.blkno || cursor.offset))
return -EINVAL;

buffer = kmem_zalloc_large(bufsize, 0);
@@ -391,7 +394,7 @@ xfs_ioc_attr_list(
*/
memset(&context, 0, sizeof(context));
context.dp = dp;
- context.cursor = cursor;
+ context.cursor = &cursor;
context.resynch = 1;
context.flags = flags;
context.buffer = buffer;
@@ -408,7 +411,8 @@ xfs_ioc_attr_list(
if (error)
goto out_free;

- if (copy_to_user(ubuf, buffer, bufsize))
+ if (copy_to_user(ubuf, buffer, bufsize) ||
+ copy_to_user(ucursor, &cursor, sizeof(cursor)))
error = -EFAULT;
out_free:
kmem_free(buffer);
@@ -418,33 +422,23 @@ xfs_ioc_attr_list(
STATIC int
xfs_attrlist_by_handle(
struct file *parfilp,
- void __user *arg)
+ struct xfs_fsop_attrlist_handlereq __user *p)
{
- int error = -ENOMEM;
- attrlist_cursor_kern_t *cursor;
- struct xfs_fsop_attrlist_handlereq __user *p = arg;
- xfs_fsop_attrlist_handlereq_t al_hreq;
+ struct xfs_fsop_attrlist_handlereq al_hreq;
struct dentry *dentry;
+ int error = -ENOMEM;

if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (copy_from_user(&al_hreq, arg, sizeof(xfs_fsop_attrlist_handlereq_t)))
+ if (copy_from_user(&al_hreq, p, sizeof(al_hreq)))
return -EFAULT;

dentry = xfs_handlereq_to_dentry(parfilp, &al_hreq.hreq);
if (IS_ERR(dentry))
return PTR_ERR(dentry);

- cursor = (attrlist_cursor_kern_t *)&al_hreq.pos;
error = xfs_ioc_attr_list(XFS_I(d_inode(dentry)), al_hreq.buffer,
- al_hreq.buflen, al_hreq.flags, cursor);
- if (error)
- goto out_dput;
-
- if (copy_to_user(&p->pos, cursor, sizeof(attrlist_cursor_kern_t)))
- error = -EFAULT;
-
-out_dput:
+ al_hreq.buflen, al_hreq.flags, &p->pos);
dput(dentry);
return error;
}
diff --git a/fs/xfs/xfs_ioctl.h b/fs/xfs/xfs_ioctl.h
index ec6448b259fb..d6e8000ad825 100644
--- a/fs/xfs/xfs_ioctl.h
+++ b/fs/xfs/xfs_ioctl.h
@@ -40,7 +40,7 @@ int xfs_ioc_attrmulti_one(struct file *parfilp, struct inode *inode,
uint32_t opcode, void __user *uname, void __user *value,
uint32_t *len, uint32_t flags);
int xfs_ioc_attr_list(struct xfs_inode *dp, void __user *ubuf, int bufsize,
- int flags, struct attrlist_cursor_kern *cursor);
+ int flags, struct xfs_attrlist_cursor __user *ucursor);

extern struct dentry *
xfs_handle_to_dentry(
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index 17e14916757b..c1771e728117 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -352,35 +352,24 @@ xfs_compat_handlereq_to_dentry(
STATIC int
xfs_compat_attrlist_by_handle(
struct file *parfilp,
- void __user *arg)
+ compat_xfs_fsop_attrlist_handlereq_t __user *p)
{
- int error;
- attrlist_cursor_kern_t *cursor;
- compat_xfs_fsop_attrlist_handlereq_t __user *p = arg;
compat_xfs_fsop_attrlist_handlereq_t al_hreq;
struct dentry *dentry;
+ int error;

if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (copy_from_user(&al_hreq, arg,
- sizeof(compat_xfs_fsop_attrlist_handlereq_t)))
+ if (copy_from_user(&al_hreq, p, sizeof(al_hreq)))
return -EFAULT;

dentry = xfs_compat_handlereq_to_dentry(parfilp, &al_hreq.hreq);
if (IS_ERR(dentry))
return PTR_ERR(dentry);

- cursor = (attrlist_cursor_kern_t *)&al_hreq.pos;
error = xfs_ioc_attr_list(XFS_I(d_inode(dentry)),
compat_ptr(al_hreq.buffer), al_hreq.buflen,
- al_hreq.flags, cursor);
- if (error)
- goto out_dput;
-
- if (copy_to_user(&p->pos, cursor, sizeof(attrlist_cursor_kern_t)))
- error = -EFAULT;
-
-out_dput:
+ al_hreq.flags, &p->pos);
dput(dentry);
return error;
}
--
2.24.1