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From: Christoph Hellwig <hch@lst.de>
To: linux-xfs@vger.kernel.org
Cc: Allison Collins <allison.henderson@oracle.com>,
	Chandan Rajendra <chandanrlinux@gmail.com>,
	"Darrick J . Wong" <darrick.wong@oracle.com>
Subject: [PATCH 05/31] xfs: use strndup_user in XFS_IOC_ATTRMULTI_BY_HANDLE
Date: Mon, 17 Feb 2020 13:59:31 +0100	[thread overview]
Message-ID: <20200217125957.263434-6-hch@lst.de> (raw)
In-Reply-To: <20200217125957.263434-1-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>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 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 b806003caacd..bb490a954c0b 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -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);
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index e085f304e539..936c2f62fb6c 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -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);
-- 
2.24.1


  parent reply	other threads:[~2020-02-17 13:00 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-17 12:59 clean up the attr interface v4 Christoph Hellwig
2020-02-17 12:59 ` [PATCH 01/31] xfs: reject invalid flags combinations in XFS_IOC_ATTRLIST_BY_HANDLE Christoph Hellwig
2020-02-17 21:48   ` Dave Chinner
2020-02-19  0:49     ` Darrick J. Wong
2020-02-17 12:59 ` [PATCH 02/31] xfs: remove the ATTR_INCOMPLETE flag Christoph Hellwig
2020-02-17 21:51   ` Dave Chinner
2020-02-18 15:19     ` Christoph Hellwig
2020-02-17 12:59 ` [PATCH 03/31] xfs: merge xfs_attr_remove into xfs_attr_set Christoph Hellwig
2020-02-17 22:02   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 04/31] xfs: merge xfs_attrmulti_attr_remove into xfs_attrmulti_attr_set Christoph Hellwig
2020-02-17 22:04   ` Dave Chinner
2020-02-17 12:59 ` Christoph Hellwig [this message]
2020-02-17 22:15   ` [PATCH 05/31] xfs: use strndup_user in XFS_IOC_ATTRMULTI_BY_HANDLE Dave Chinner
2020-02-18 15:24     ` Christoph Hellwig
2020-02-19  0:38       ` Darrick J. Wong
2020-02-19  4:03         ` Dave Chinner
2020-02-17 12:59 ` [PATCH 06/31] xfs: factor out a helper for a single XFS_IOC_ATTRMULTI_BY_HANDLE op Christoph Hellwig
2020-02-17 22:28   ` Dave Chinner
2020-02-18 15:28     ` Christoph Hellwig
2020-02-17 12:59 ` [PATCH 07/31] xfs: remove the name == NULL check from xfs_attr_args_init Christoph Hellwig
2020-02-17 22:29   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 08/31] xfs: remove the MAXNAMELEN " Christoph Hellwig
2020-02-17 22:29   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 09/31] xfs: move struct xfs_da_args to xfs_types.h Christoph Hellwig
2020-02-17 12:59 ` [PATCH 10/31] xfs: turn xfs_da_args.value into a void pointer Christoph Hellwig
2020-02-17 12:59 ` [PATCH 11/31] xfs: pass an initialized xfs_da_args structure to xfs_attr_set Christoph Hellwig
2020-02-17 12:59 ` [PATCH 12/31] xfs: pass an initialized xfs_da_args to xfs_attr_get Christoph Hellwig
2020-02-17 12:59 ` [PATCH 13/31] xfs: remove the xfs_inode argument to xfs_attr_get_ilocked Christoph Hellwig
2020-02-17 23:06   ` Dave Chinner
2020-02-18 15:30     ` Christoph Hellwig
2020-02-17 12:59 ` [PATCH 14/31] xfs: remove ATTR_KERNOVAL Christoph Hellwig
2020-02-17 23:06   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 15/31] xfs: remove ATTR_ALLOC and XFS_DA_OP_ALLOCVAL Christoph Hellwig
2020-02-17 23:09   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 16/31] xfs: replace ATTR_KERNOTIME with XFS_DA_OP_NOTIME Christoph Hellwig
2020-02-17 23:21   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 17/31] xfs: factor out a xfs_attr_match helper Christoph Hellwig
2020-02-17 23:23   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 18/31] xfs: cleanup struct xfs_attr_list_context Christoph Hellwig
2020-02-17 23:25   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 19/31] xfs: remove the unused ATTR_ENTRY macro Christoph Hellwig
2020-02-17 23:25   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 20/31] xfs: open code ATTR_ENTSIZE Christoph Hellwig
2020-02-17 23:32   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 21/31] xfs: move the legacy xfs_attr_list to xfs_ioctl.c Christoph Hellwig
2020-02-17 23:41   ` Dave Chinner
2020-02-18 15:38     ` Christoph Hellwig
2020-02-17 12:59 ` [PATCH 22/31] xfs: rename xfs_attr_list_int to xfs_attr_list Christoph Hellwig
2020-02-17 23:42   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 23/31] xfs: properly type the buffer field in struct xfs_fsop_attrlist_handlereq Christoph Hellwig
2020-02-17 23:53   ` Dave Chinner
2020-02-18 15:39     ` Christoph Hellwig
2020-02-19  0:58       ` Darrick J. Wong
2020-02-19  4:10         ` Dave Chinner
2020-02-17 12:59 ` [PATCH 24/31] xfs: lift common checks into xfs_ioc_attr_list Christoph Hellwig
2020-02-17 23:47   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 25/31] xfs: lift buffer allocation " Christoph Hellwig
2020-02-17 23:55   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 26/31] xfs: lift cursor copy in/out " Christoph Hellwig
2020-02-18  0:03   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 27/31] xfs: improve xfs_forget_acl Christoph Hellwig
2020-02-18  1:58   ` Dave Chinner
2020-02-17 12:59 ` [PATCH 28/31] xfs: clean up the ATTR_REPLACE checks Christoph Hellwig
2020-02-18  2:06   ` Dave Chinner
2020-02-18 15:41     ` Christoph Hellwig
2020-02-17 12:59 ` [PATCH 29/31] xfs: clean up the attr flag confusion Christoph Hellwig
2020-02-17 12:59 ` [PATCH 30/31] xfs: remove XFS_DA_OP_INCOMPLETE Christoph Hellwig
2020-02-18  2:23   ` Dave Chinner
2020-02-18 15:48     ` Christoph Hellwig
2020-02-19  0:47       ` Darrick J. Wong
2020-02-19  6:53         ` Dave Chinner
2020-02-17 12:59 ` [PATCH 31/31] xfs: embedded the attrlist cursor into struct xfs_attr_list_context Christoph Hellwig
2020-02-18  2:24   ` Dave Chinner
2020-02-19  0:48 ` clean up the attr interface v4 Darrick J. Wong
  -- strict thread matches above, loose matches on Subject: below --
2020-02-21 14:11 clean up the attr interface v5 Christoph Hellwig
2020-02-21 14:11 ` [PATCH 05/31] xfs: use strndup_user in XFS_IOC_ATTRMULTI_BY_HANDLE Christoph Hellwig

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