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Message-Id: <11887860591926-git-send-email-jsipek@cs.sunysb.edu>
Date: Sun, 2 Sep 2007 22:20:50 -0400
From: "Josef 'Jeff' Sipek" <jsipek@...sunysb.edu>
To: akpm@...ux-foundation.org
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
hch@...radead.org, viro@....linux.org.uk,
bharata@...ux.vnet.ibm.com, j.blunck@...harburg.de,
Erez Zadok <ezk@...sunysb.edu>,
"Josef 'Jeff' Sipek" <jsipek@...sunysb.edu>
Subject: [PATCH 27/32] Unionfs: extended attributes fixes
From: Erez Zadok <ezk@...sunysb.edu>
Signed-off-by: Erez Zadok <ezk@...sunysb.edu>
Signed-off-by: Josef 'Jeff' Sipek <jsipek@...sunysb.edu>
---
fs/unionfs/copyup.c | 43 +++++++++++++++++++++++++++++++------------
fs/unionfs/union.h | 6 ++++--
fs/unionfs/xattr.c | 16 ++--------------
3 files changed, 37 insertions(+), 28 deletions(-)
diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
index 4c45790..36f751e 100644
--- a/fs/unionfs/copyup.c
+++ b/fs/unionfs/copyup.c
@@ -32,27 +32,39 @@ static int copyup_xattrs(struct dentry *old_lower_dentry,
ssize_t list_size = -1;
char *name_list = NULL;
char *attr_value = NULL;
- char *name_list_orig = NULL;
+ char *name_list_buf = NULL;
+ /* query the actual size of the xattr list */
list_size = vfs_listxattr(old_lower_dentry, NULL, 0);
-
if (list_size <= 0) {
err = list_size;
goto out;
}
+ /* allocate space for the actual list */
name_list = unionfs_xattr_alloc(list_size + 1, XATTR_LIST_MAX);
if (!name_list || IS_ERR(name_list)) {
err = PTR_ERR(name_list);
goto out;
}
+
+ name_list_buf = name_list; /* save for kfree at end */
+
+ /* now get the actual xattr list of the source file */
list_size = vfs_listxattr(old_lower_dentry, name_list, list_size);
+ if (list_size <= 0) {
+ err = list_size;
+ goto out;
+ }
+
+ /* allocate space to hold each xattr's value */
attr_value = unionfs_xattr_alloc(XATTR_SIZE_MAX, XATTR_SIZE_MAX);
if (!attr_value || IS_ERR(attr_value)) {
err = PTR_ERR(name_list);
goto out;
}
- name_list_orig = name_list;
+
+ /* in a loop, get and set each xattr from src to dst file */
while (*name_list) {
ssize_t size;
@@ -65,7 +77,6 @@ static int copyup_xattrs(struct dentry *old_lower_dentry,
err = size;
goto out;
}
-
if (size > XATTR_SIZE_MAX) {
err = -E2BIG;
goto out;
@@ -73,19 +84,27 @@ static int copyup_xattrs(struct dentry *old_lower_dentry,
/* Don't lock here since vfs_setxattr does it for us. */
err = vfs_setxattr(new_lower_dentry, name_list, attr_value,
size, 0);
-
+ /*
+ * Selinux depends on "security.*" xattrs, so to maintain
+ * the security of copied-up files, if Selinux is active,
+ * then we must copy these xattrs as well. So we need to
+ * temporarily get FOWNER privileges.
+ * XXX: move entire copyup code to SIOQ.
+ */
+ if (err == -EPERM && !capable(CAP_FOWNER)) {
+ cap_raise(current->cap_effective, CAP_FOWNER);
+ err = vfs_setxattr(new_lower_dentry, name_list,
+ attr_value, size, 0);
+ cap_lower(current->cap_effective, CAP_FOWNER);
+ }
if (err < 0)
goto out;
name_list += strlen(name_list) + 1;
}
out:
- name_list = name_list_orig;
-
- if (name_list)
- unionfs_xattr_free(name_list, list_size + 1);
- if (attr_value)
- unionfs_xattr_free(attr_value, XATTR_SIZE_MAX);
- /* It is no big deal if this fails, we just roll with the punches. */
+ unionfs_xattr_kfree(name_list_buf);
+ unionfs_xattr_kfree(attr_value);
+ /* Ignore if xattr isn't supported */
if (err == -ENOTSUPP || err == -EOPNOTSUPP)
err = 0;
return err;
diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
index 26d886e..d1232ac 100644
--- a/fs/unionfs/union.h
+++ b/fs/unionfs/union.h
@@ -341,8 +341,10 @@ extern struct dentry *unionfs_interpose(struct dentry *this_dentry,
#ifdef CONFIG_UNION_FS_XATTR
/* Extended attribute functions. */
extern void *unionfs_xattr_alloc(size_t size, size_t limit);
-extern void unionfs_xattr_free(void *ptr, size_t size);
-
+static inline void unionfs_xattr_kfree(const void *p)
+{
+ kfree(p);
+}
extern ssize_t unionfs_getxattr(struct dentry *dentry, const char *name,
void *value, size_t size);
extern int unionfs_removexattr(struct dentry *dentry, const char *name);
diff --git a/fs/unionfs/xattr.c b/fs/unionfs/xattr.c
index 46f3d4e..6ab92f3 100644
--- a/fs/unionfs/xattr.c
+++ b/fs/unionfs/xattr.c
@@ -28,25 +28,13 @@ void *unionfs_xattr_alloc(size_t size, size_t limit)
if (!size) /* size request, no buffer is needed */
return NULL;
- else if (size <= PAGE_SIZE)
- ptr = kmalloc(size, GFP_KERNEL);
- else
- ptr = vmalloc(size);
+
+ ptr = kmalloc(size, GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
return ptr;
}
-void unionfs_xattr_free(void *ptr, size_t size)
-{
- if (!size) /* size request, no buffer was needed */
- return;
- else if (size <= PAGE_SIZE)
- kfree(ptr);
- else
- vfree(ptr);
-}
-
/*
* BKL held by caller.
* dentry->d_inode->i_mutex locked
--
1.5.2.2.238.g7cbf2f2
-
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