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xfs: use strndup_user in XFS_IOC_ATTRMULTI_BY_HANDLE

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Simplify the user copy code by using strndup_user.  This means that we
now do one memory allocation per operation instead of one per ioctl,
but memory allocations are cheap compared to the actual file system
operations.  Also the error for an invalid path is now EINVAL or EFAULT
instead of the previous odd and undocumented ERANGE.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Christoph Hellwig 2020-02-26 17:30:31 -08:00 committed by Darrick J. Wong
parent 6cc4f4fff1
commit 2282a9e651
2 changed files with 10 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
fs/xfs/xfs_ioctl.c
View File

@ -448,11 +448,6 @@ xfs_attrmulti_by_handle(
goto out_dput;
}
error = -ENOMEM;
attr_name = kmalloc(MAXNAMELEN, GFP_KERNEL);
if (!attr_name)
goto out_kfree_ops;
error = 0;
for (i = 0; i < am_hreq.opcount; i++) {
if ((ops[i].am_flags & ATTR_ROOT) &&
@ -462,12 +457,11 @@ xfs_attrmulti_by_handle(
}
ops[i].am_flags &= ~ATTR_KERNEL_FLAGS;
ops[i].am_error = strncpy_from_user((char *)attr_name,
ops[i].am_attrname, MAXNAMELEN);
if (ops[i].am_error == 0 || ops[i].am_error == MAXNAMELEN)
error = -ERANGE;
if (ops[i].am_error < 0)
attr_name = strndup_user(ops[i].am_attrname, MAXNAMELEN);
if (IS_ERR(attr_name)) {
ops[i].am_error = PTR_ERR(attr_name);
break;
}
switch (ops[i].am_opcode) {
case ATTR_OP_GET:
@ -498,13 +492,12 @@ xfs_attrmulti_by_handle(
default:
ops[i].am_error = -EINVAL;
}
kfree(attr_name);
}
if (copy_to_user(am_hreq.ops, ops, size))
error = -EFAULT;
kfree(attr_name);
out_kfree_ops:
kfree(ops);
out_dput:
dput(dentry);

17
fs/xfs/xfs_ioctl32.c
View File

@ -445,11 +445,6 @@ xfs_compat_attrmulti_by_handle(
goto out_dput;
}
error = -ENOMEM;
attr_name = kmalloc(MAXNAMELEN, GFP_KERNEL);
if (!attr_name)
goto out_kfree_ops;
error = 0;
for (i = 0; i < am_hreq.opcount; i++) {
if ((ops[i].am_flags & ATTR_ROOT) &&
@ -459,13 +454,12 @@ xfs_compat_attrmulti_by_handle(
}
ops[i].am_flags &= ~ATTR_KERNEL_FLAGS;
ops[i].am_error = strncpy_from_user((char *)attr_name,
compat_ptr(ops[i].am_attrname),
attr_name = strndup_user(compat_ptr(ops[i].am_attrname),
MAXNAMELEN);
if (ops[i].am_error == 0 || ops[i].am_error == MAXNAMELEN)
error = -ERANGE;
if (ops[i].am_error < 0)
if (IS_ERR(attr_name)) {
ops[i].am_error = PTR_ERR(attr_name);
break;
}
switch (ops[i].am_opcode) {
case ATTR_OP_GET:
@ -496,13 +490,12 @@ xfs_compat_attrmulti_by_handle(
default:
ops[i].am_error = -EINVAL;
}
kfree(attr_name);
}
if (copy_to_user(compat_ptr(am_hreq.ops), ops, size))
error = -EFAULT;
kfree(attr_name);
out_kfree_ops:
kfree(ops);
out_dput:
dput(dentry);