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From: Stefan Roesch <[email protected]>
To: <[email protected]>, <[email protected]>,
	<[email protected]>, <[email protected]>,
	<[email protected]>
Cc: <[email protected]>, <[email protected]>, <[email protected]>,
	<[email protected]>, <[email protected]>,
	Christoph Hellwig <[email protected]>
Subject: [PATCH v7 08/15] fs: add __remove_file_privs() with flags parameter
Date: Wed, 1 Jun 2022 14:01:34 -0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

This adds the function __remove_file_privs, which allows the caller to
pass the kiocb flags parameter.

No intended functional changes in this patch.

Signed-off-by: Stefan Roesch <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
 fs/inode.c | 57 +++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 37 insertions(+), 20 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 9d9b422504d1..ac1cf5aa78c8 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2010,36 +2010,43 @@ static int __remove_privs(struct user_namespace *mnt_userns,
 	return notify_change(mnt_userns, dentry, &newattrs, NULL);
 }
 
-/*
- * Remove special file priviledges (suid, capabilities) when file is written
- * to or truncated.
- */
-int file_remove_privs(struct file *file)
+static int __file_remove_privs(struct file *file, unsigned int flags)
 {
 	struct dentry *dentry = file_dentry(file);
 	struct inode *inode = file_inode(file);
+	int error;
 	int kill;
-	int error = 0;
 
-	/*
-	 * Fast path for nothing security related.
-	 * As well for non-regular files, e.g. blkdev inodes.
-	 * For example, blkdev_write_iter() might get here
-	 * trying to remove privs which it is not allowed to.
-	 */
 	if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode))
 		return 0;
 
 	kill = dentry_needs_remove_privs(dentry);
-	if (kill < 0)
+	if (kill <= 0)
 		return kill;
-	if (kill)
-		error = __remove_privs(file_mnt_user_ns(file), dentry, kill);
+
+	if (flags & IOCB_NOWAIT)
+		return -EAGAIN;
+
+	error = __remove_privs(file_mnt_user_ns(file), dentry, kill);
 	if (!error)
 		inode_has_no_xattr(inode);
 
 	return error;
 }
+
+/**
+ * file_remove_privs - remove special file privileges (suid, capabilities)
+ * @file: file to remove privileges from
+ *
+ * When file is modified by a write or truncation ensure that special
+ * file privileges are removed.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int file_remove_privs(struct file *file)
+{
+	return __file_remove_privs(file, 0);
+}
 EXPORT_SYMBOL(file_remove_privs);
 
 /**
@@ -2090,18 +2097,28 @@ int file_update_time(struct file *file)
 }
 EXPORT_SYMBOL(file_update_time);
 
-/* Caller must hold the file's inode lock */
+/**
+ * file_modified - handle mandated vfs changes when modifying a file
+ * @file: file that was modified
+ *
+ * When file has been modified ensure that special
+ * file privileges are removed and time settings are updated.
+ *
+ * Context: Caller must hold the file's inode lock.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
 int file_modified(struct file *file)
 {
-	int err;
+	int ret;
 
 	/*
 	 * Clear the security bits if the process is not being run by root.
 	 * This keeps people from modifying setuid and setgid binaries.
 	 */
-	err = file_remove_privs(file);
-	if (err)
-		return err;
+	ret = __file_remove_privs(file, 0);
+	if (ret)
+		return ret;
 
 	if (unlikely(file->f_mode & FMODE_NOCMTIME))
 		return 0;
-- 
2.30.2


  parent reply	other threads:[~2022-06-01 21:07 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-01 21:01 [PATCH v7 00/15] io-uring/xfs: support async buffered writes Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 01/15] mm: Move starting of background writeback into the main balancing loop Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 02/15] mm: Move updates of dirty_exceeded into one place Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 03/15] mm: Add balance_dirty_pages_ratelimited_flags() function Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 04/15] iomap: Add flags parameter to iomap_page_create() Stefan Roesch
2022-06-02 16:26   ` Darrick J. Wong
2022-06-01 21:01 ` [PATCH v7 05/15] iomap: Add async buffered write support Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 06/15] iomap: Return error code from iomap_write_iter() Stefan Roesch
2022-06-02 12:38   ` Matthew Wilcox
2022-06-02 17:08     ` Stefan Roesch
2022-06-06 16:39     ` Stefan Roesch
2022-06-06 19:18       ` Matthew Wilcox
2022-06-06 19:21         ` Stefan Roesch
2022-06-06 19:25           ` Matthew Wilcox
2022-06-06 19:28             ` Stefan Roesch
2022-06-06 20:30               ` Matthew Wilcox
2022-06-06 20:34                 ` Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 07/15] fs: Add check for async buffered writes to generic_write_checks Stefan Roesch
2022-06-01 21:01 ` Stefan Roesch [this message]
2022-06-02  9:04   ` [PATCH v7 08/15] fs: add __remove_file_privs() with flags parameter Jan Kara
2022-06-01 21:01 ` [PATCH v7 09/15] fs: Split off inode_needs_update_time and __file_update_time Stefan Roesch
2022-06-02  8:44   ` Jan Kara
2022-06-02 12:57   ` Matthew Wilcox
2022-06-02 21:04     ` Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 10/15] fs: Add async write file modification handling Stefan Roesch
2022-06-02  8:44   ` Jan Kara
2022-06-02  9:06   ` Jan Kara
2022-06-02 21:00     ` Stefan Roesch
2022-06-03 10:12       ` Jan Kara
2022-06-06 16:35         ` Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 11/15] fs: Optimization for concurrent file time updates Stefan Roesch
2022-06-02  8:59   ` Jan Kara
2022-06-02 21:06     ` Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 12/15] io_uring: Add support for async buffered writes Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 13/15] io_uring: Add tracepoint for short writes Stefan Roesch
2022-06-01 21:01 ` [PATCH v7 14/15] xfs: Specify lockmode when calling xfs_ilock_for_iomap() Stefan Roesch
2022-06-02 16:25   ` Darrick J. Wong
2022-06-01 21:01 ` [PATCH v7 15/15] xfs: Add async buffered write support Stefan Roesch
2022-07-01  4:39   ` Al Viro
2022-07-01 14:19     ` Jens Axboe
2022-07-01 14:30       ` Jens Axboe
2022-07-01 14:38         ` Jens Axboe
2022-07-01 18:05           ` Darrick J. Wong
2022-07-01 18:14             ` Jens Axboe
2022-07-05 13:47               ` Josef Bacik
2022-07-05 14:23                 ` Goldwyn Rodrigues
2022-07-05 16:11                 ` Christoph Hellwig
2022-06-02  8:09 ` [PATCH v7 00/15] io-uring/xfs: support async buffered writes Jens Axboe
2022-06-03  2:43   ` Dave Chinner
2022-06-03 13:04     ` Jens Axboe
2022-06-07 16:41       ` Stefan Roesch

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