eCryptfs: fix permission denied with ecryptfs_xattr mount option when create readonly file (d43388de) · Commits · 戴 / test

When the ecryptfs_xattr mount option is turned on, the ecryptfs metadata will be written to xattr via vfs_setxattr, which will check the WRITE permissions. However, this will cause denial of permission when creating a file withoug write permission. So fix this by calling __vfs_setxattr directly to skip permission check. Signed-off-by:

Robbie Ko <robbieko@synology.com> [tyhicks: Copy up lower inode attributes when successful] Signed-off-by:

Tyler Hicks <tyhicks@canonical.com>

fs/ecryptfs/crypto.c

+15 −2

Original line number	Diff line number	Diff line
		@@ -37,6 +37,7 @@
		#include <linux/slab.h>
		#include <asm/unaligned.h>
		#include <linux/kernel.h>
		#include <linux/xattr.h>
		#include "ecryptfs_kernel.h"

		#define DECRYPT 0
		@@ -1131,9 +1132,21 @@ ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
		char *page_virt, size_t size)
		{
		int rc;
		struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
		struct inode *lower_inode = d_inode(lower_dentry);

		rc = ecryptfs_setxattr(ecryptfs_dentry, ecryptfs_inode,
		ECRYPTFS_XATTR_NAME, page_virt, size, 0);
		if (!(lower_inode->i_opflags & IOP_XATTR)) {
		rc = -EOPNOTSUPP;
		goto out;
		}

		inode_lock(lower_inode);
		rc = __vfs_setxattr(lower_dentry, lower_inode, ECRYPTFS_XATTR_NAME,
		page_virt, size, 0);
		if (!rc && ecryptfs_inode)
		fsstack_copy_attr_all(ecryptfs_inode, lower_inode);
		inode_unlock(lower_inode);
		out:
		return rc;
		}

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