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From: Christoph Hellwig <hch@lst.de>
To: linux-xfs@vger.kernel.org
Cc: Allison Collins <allison.henderson@oracle.com>
Subject: [PATCH 08/33] xfs: use strndup_user in XFS_IOC_ATTRMULTI_BY_HANDLE
Date: Thu, 12 Dec 2019 11:54:08 +0100	[thread overview]
Message-ID: <20191212105433.1692-9-hch@lst.de> (raw)
In-Reply-To: <20191212105433.1692-1-hch@lst.de>

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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_ioctl.c   | 17 +++++------------
 fs/xfs/xfs_ioctl32.c | 17 +++++------------
 2 files changed, 10 insertions(+), 24 deletions(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 7f3cd5648e7a..2e81d354b37d 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -441,11 +441,6 @@ 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) &&
@@ -455,12 +450,11 @@ 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:
@@ -491,13 +485,12 @@ 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);
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index 76b1382c2214..ffcf175efc48 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -443,11 +443,6 @@ 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) &&
@@ -457,13 +452,12 @@ 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:
@@ -494,13 +488,12 @@ 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);
-- 
2.20.1


  parent reply	other threads:[~2019-12-12 10:54 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-12 10:54 clean up the attr interface Christoph Hellwig
2019-12-12 10:54 ` [PATCH 01/33] xfs: clear kernel only flags in XFS_IOC_ATTRMULTI_BY_HANDLE Christoph Hellwig
2019-12-18 21:26   ` Darrick J. Wong
2019-12-24 11:56     ` Christoph Hellwig
2019-12-12 10:54 ` [PATCH 02/33] xfs: reject invalid flags combinations " Christoph Hellwig
2019-12-18 21:29   ` Darrick J. Wong
2019-12-24 11:56     ` Christoph Hellwig
2019-12-12 10:54 ` [PATCH 03/33] xfs: also remove cached ACLs when removing the underlying attr Christoph Hellwig
2019-12-18 21:31   ` Darrick J. Wong
2019-12-24 11:57     ` Christoph Hellwig
2019-12-12 10:54 ` [PATCH 04/33] xfs: fix misuse of the XFS_ATTR_INCOMPLETE flag Christoph Hellwig
2019-12-18 21:33   ` Darrick J. Wong
2019-12-12 10:54 ` [PATCH 05/33] xfs: remove the ATTR_INCOMPLETE flag Christoph Hellwig
2019-12-18 21:43   ` Darrick J. Wong
2019-12-24 11:59     ` Christoph Hellwig
2019-12-12 10:54 ` [PATCH 06/33] xfs: merge xfs_attr_remove into xfs_attr_set Christoph Hellwig
2019-12-12 10:54 ` [PATCH 07/33] xfs: merge xfs_attrmulti_attr_remove into xfs_attrmulti_attr_set Christoph Hellwig
2019-12-12 10:54 ` Christoph Hellwig [this message]
2019-12-12 10:54 ` [PATCH 09/33] xfs: factour out a helper for a single XFS_IOC_ATTRMULTI_BY_HANDLE op Christoph Hellwig
2019-12-12 10:54 ` [PATCH 10/33] xfs: remove the name == NULL check from xfs_attr_args_init Christoph Hellwig
2019-12-12 10:54 ` [PATCH 11/33] xfs: remove the MAXNAMELEN " Christoph Hellwig
2019-12-12 10:54 ` [PATCH 12/33] xfs: move struct xfs_da_args to xfs_types.h Christoph Hellwig
2019-12-12 10:54 ` [PATCH 13/33] xfs: turn xfs_da_args.value into a void pointer Christoph Hellwig
2019-12-12 10:54 ` [PATCH 14/33] xfs: pass an initialized xfs_da_args structure to xfs_attr_set Christoph Hellwig
2019-12-12 10:54 ` [PATCH 15/33] xfs: pass an initialized xfs_da_args to xfs_attr_get Christoph Hellwig
2019-12-12 10:54 ` [PATCH 16/33] xfs: remove the xfs_inode argument to xfs_attr_get_ilocked Christoph Hellwig
2019-12-12 10:54 ` [PATCH 17/33] xfs: remove ATTR_KERNOVAL Christoph Hellwig
2019-12-12 10:54 ` [PATCH 18/33] xfs: remove ATTR_ALLOC and XFS_DA_OP_ALLOCVAL Christoph Hellwig
2019-12-12 10:54 ` [PATCH 19/33] xfs: replace ATTR_KERNOTIME with XFS_DA_OP_NOTIME Christoph Hellwig
2019-12-12 10:54 ` [PATCH 20/33] xfs: factor out a xfs_attr_match helper Christoph Hellwig
2019-12-12 10:54 ` [PATCH 21/33] xfs: cleanup xfs_attr_list_context Christoph Hellwig
2019-12-12 10:54 ` [PATCH 22/33] xfs: remove the unused ATTR_ENTRY macro Christoph Hellwig
2019-12-12 10:54 ` [PATCH 23/33] xfs: replace ATTR_ENTBASESIZE with offsetoff Christoph Hellwig
2019-12-12 10:54 ` [PATCH 24/33] xfs: move the legacy xfs_attr_list to xfs_ioctl.c Christoph Hellwig
2019-12-12 10:54 ` [PATCH 25/33] xfs: rename xfs_attr_list_int to xfs_attr_list Christoph Hellwig
2019-12-12 10:54 ` [PATCH 26/33] xfs: lift common check into xfs_ioc_attr_list Christoph Hellwig
2019-12-12 10:54 ` [PATCH 27/33] xfs: lift buffer allocation " Christoph Hellwig
2019-12-12 10:54 ` [PATCH 28/33] xfs: lift cursor copy in/out " Christoph Hellwig
2019-12-12 10:54 ` [PATCH 29/33] xfs: improve xfs_forget_acl Christoph Hellwig
2019-12-12 10:54 ` [PATCH 30/33] xfs: clean up the ATTR_REPLACE checks Christoph Hellwig
2019-12-12 10:54 ` [PATCH 31/33] xfs: clean up the attr flag confusion Christoph Hellwig
2019-12-12 10:54 ` [PATCH 32/33] xfs: remove XFS_DA_OP_INCOMPLETE Christoph Hellwig
2019-12-12 10:54 ` [PATCH 33/33] xfs: embedded the attrlist cursor into struct xfs_attr_list_context Christoph Hellwig

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