[PATCH v2 04/11] vfs: Distinguish between full xattr names and proper prefixes

From: Andreas Gruenbacher
Date: Wed Dec 02 2015 - 08:49:39 EST

Add an additional "name" field to struct xattr_handler. When the name
is set, the handler matches attributes with exactly that name. When the
prefix is set instead, the handler matches attributes with the given
prefix and with a non-empty suffix.

This patch should avoid bugs like the one fixed in commit c361016a in
the future.

Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Reviewed-by: James Morris <james.l.morris@xxxxxxxxxx>
---
fs/9p/acl.c | 16 +++++-----------
fs/9p/xattr.c | 4 ----
fs/ext2/xattr_security.c | 4 ----
fs/ext2/xattr_trusted.c | 4 ----
fs/ext2/xattr_user.c | 4 ----
fs/ext4/xattr_security.c | 4 ----
fs/ext4/xattr_trusted.c | 4 ----
fs/ext4/xattr_user.c | 4 ----
fs/f2fs/xattr.c | 20 ++++++--------------
fs/f2fs/xattr.h | 2 +-
fs/hfsplus/xattr.c | 12 ------------
fs/jffs2/security.c | 6 ------
fs/jffs2/xattr_trusted.c | 4 ----
fs/jffs2/xattr_user.c | 4 ----
fs/nfs/nfs4proc.c | 8 +-------
fs/ocfs2/xattr.c | 17 +----------------
fs/posix_acl.c | 10 +++-------
fs/reiserfs/xattr.c | 3 ++-
fs/squashfs/xattr.c | 3 ---
fs/xattr.c | 27 +++++++++++++++++----------
fs/xfs/xfs_xattr.c | 6 ------
include/linux/xattr.h | 11 +++++++++++
22 files changed, 47 insertions(+), 130 deletions(-)

diff --git a/fs/9p/acl.c b/fs/9p/acl.c
index 6ff30b1..9da967f 100644
--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -220,15 +220,12 @@ static int v9fs_xattr_get_acl(const struct xattr_handler *handler,
struct posix_acl *acl;
int error;

- if (strcmp(name, "") != 0)
- return -EINVAL;
-
v9ses = v9fs_dentry2v9ses(dentry);
/*
* We allow set/get/list of acl when access=client is not specified
*/
if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
- return v9fs_xattr_get(dentry, handler->prefix, buffer, size);
+ return v9fs_xattr_get(dentry, handler->name, buffer, size);

acl = v9fs_get_cached_acl(d_inode(dentry), handler->flags);
if (IS_ERR(acl))
@@ -250,16 +247,13 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
struct v9fs_session_info *v9ses;
struct inode *inode = d_inode(dentry);

- if (strcmp(name, "") != 0)
- return -EINVAL;
-
v9ses = v9fs_dentry2v9ses(dentry);
/*
* set the attribute on the remote. Without even looking at the
* xattr value. We leave it to the server to validate
*/
if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
- return v9fs_xattr_set(dentry, handler->prefix, value, size,
+ return v9fs_xattr_set(dentry, handler->name, value, size,
flags);

if (S_ISLNK(inode->i_mode))
@@ -319,7 +313,7 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
default:
BUG();
}
- retval = v9fs_xattr_set(dentry, handler->prefix, value, size, flags);
+ retval = v9fs_xattr_set(dentry, handler->name, value, size, flags);
if (!retval)
set_cached_acl(inode, handler->flags, acl);
err_out:
@@ -328,14 +322,14 @@ err_out:
}

const struct xattr_handler v9fs_xattr_acl_access_handler = {
- .prefix = XATTR_NAME_POSIX_ACL_ACCESS,
+ .name = XATTR_NAME_POSIX_ACL_ACCESS,
.flags = ACL_TYPE_ACCESS,
.get = v9fs_xattr_get_acl,
.set = v9fs_xattr_set_acl,
};

const struct xattr_handler v9fs_xattr_acl_default_handler = {
- .prefix = XATTR_NAME_POSIX_ACL_DEFAULT,
+ .name = XATTR_NAME_POSIX_ACL_DEFAULT,
.flags = ACL_TYPE_DEFAULT,
.get = v9fs_xattr_get_acl,
.set = v9fs_xattr_set_acl,
diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
index e3d026a..9dd9b47 100644
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -143,8 +143,6 @@ static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
{
const char *full_name = xattr_full_name(handler, name);

- if (strcmp(name, "") == 0)
- return -EINVAL;
return v9fs_xattr_get(dentry, full_name, buffer, size);
}

@@ -154,8 +152,6 @@ static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
{
const char *full_name = xattr_full_name(handler, name);

- if (strcmp(name, "") == 0)
- return -EINVAL;
return v9fs_xattr_set(dentry, full_name, value, size, flags);
}

diff --git a/fs/ext2/xattr_security.c b/fs/ext2/xattr_security.c
index dfb0875..118bf23 100644
--- a/fs/ext2/xattr_security.c
+++ b/fs/ext2/xattr_security.c
@@ -28,8 +28,6 @@ ext2_xattr_security_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ext2_xattr_get(d_inode(dentry), EXT2_XATTR_INDEX_SECURITY, name,
buffer, size);
}
@@ -39,8 +37,6 @@ ext2_xattr_security_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ext2_xattr_set(d_inode(dentry), EXT2_XATTR_INDEX_SECURITY, name,
value, size, flags);
}
diff --git a/fs/ext2/xattr_trusted.c b/fs/ext2/xattr_trusted.c
index 3150dd3..3f8f2bc 100644
--- a/fs/ext2/xattr_trusted.c
+++ b/fs/ext2/xattr_trusted.c
@@ -32,8 +32,6 @@ ext2_xattr_trusted_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ext2_xattr_get(d_inode(dentry), EXT2_XATTR_INDEX_TRUSTED, name,
buffer, size);
}
@@ -43,8 +41,6 @@ ext2_xattr_trusted_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ext2_xattr_set(d_inode(dentry), EXT2_XATTR_INDEX_TRUSTED, name,
value, size, flags);
}
diff --git a/fs/ext2/xattr_user.c b/fs/ext2/xattr_user.c
index 339a49b..afd45ab 100644
--- a/fs/ext2/xattr_user.c
+++ b/fs/ext2/xattr_user.c
@@ -34,8 +34,6 @@ ext2_xattr_user_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
if (!test_opt(dentry->d_sb, XATTR_USER))
return -EOPNOTSUPP;
return ext2_xattr_get(d_inode(dentry), EXT2_XATTR_INDEX_USER,
@@ -47,8 +45,6 @@ ext2_xattr_user_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
if (!test_opt(dentry->d_sb, XATTR_USER))
return -EOPNOTSUPP;

diff --git a/fs/ext4/xattr_security.c b/fs/ext4/xattr_security.c
index 36f4c1a..195abc4 100644
--- a/fs/ext4/xattr_security.c
+++ b/fs/ext4/xattr_security.c
@@ -33,8 +33,6 @@ ext4_xattr_security_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ext4_xattr_get(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
name, buffer, size);
}
@@ -44,8 +42,6 @@ ext4_xattr_security_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ext4_xattr_set(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
name, value, size, flags);
}
diff --git a/fs/ext4/xattr_trusted.c b/fs/ext4/xattr_trusted.c
index 4880890..121fdf9 100644
--- a/fs/ext4/xattr_trusted.c
+++ b/fs/ext4/xattr_trusted.c
@@ -36,8 +36,6 @@ ext4_xattr_trusted_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name, void *buffer,
size_t size)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ext4_xattr_get(d_inode(dentry), EXT4_XATTR_INDEX_TRUSTED,
name, buffer, size);
}
@@ -47,8 +45,6 @@ ext4_xattr_trusted_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ext4_xattr_set(d_inode(dentry), EXT4_XATTR_INDEX_TRUSTED,
name, value, size, flags);
}
diff --git a/fs/ext4/xattr_user.c b/fs/ext4/xattr_user.c
index d2dec33..577fc12 100644
--- a/fs/ext4/xattr_user.c
+++ b/fs/ext4/xattr_user.c
@@ -35,8 +35,6 @@ ext4_xattr_user_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
if (!test_opt(dentry->d_sb, XATTR_USER))
return -EOPNOTSUPP;
return ext4_xattr_get(d_inode(dentry), EXT4_XATTR_INDEX_USER,
@@ -48,8 +46,6 @@ ext4_xattr_user_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
if (!test_opt(dentry->d_sb, XATTR_USER))
return -EOPNOTSUPP;
return ext4_xattr_set(d_inode(dentry), EXT4_XATTR_INDEX_USER,
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index 862368a..21cfe51 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -30,6 +30,7 @@ static size_t f2fs_xattr_generic_list(const struct xattr_handler *handler,
const char *name, size_t len)
{
struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
+ const char *prefix;
int total_len, prefix_len;

switch (handler->flags) {
@@ -47,10 +48,11 @@ static size_t f2fs_xattr_generic_list(const struct xattr_handler *handler,
return -EINVAL;
}

- prefix_len = strlen(handler->prefix);
+ prefix = xattr_prefix(handler);
+ prefix_len = strlen(prefix);
total_len = prefix_len + len + 1;
if (list && total_len <= list_size) {
- memcpy(list, handler->prefix, prefix_len);
+ memcpy(list, prefix, prefix_len);
memcpy(list + prefix_len, name, len);
list[prefix_len + len] = '\0';
}
@@ -77,8 +79,6 @@ static int f2fs_xattr_generic_get(const struct xattr_handler *handler,
default:
return -EINVAL;
}
- if (strcmp(name, "") == 0)
- return -EINVAL;
return f2fs_getxattr(d_inode(dentry), handler->flags, name,
buffer, size, NULL);
}
@@ -103,9 +103,6 @@ static int f2fs_xattr_generic_set(const struct xattr_handler *handler,
default:
return -EINVAL;
}
- if (strcmp(name, "") == 0)
- return -EINVAL;
-
return f2fs_setxattr(d_inode(dentry), handler->flags, name,
value, size, NULL, flags);
}
@@ -114,7 +111,7 @@ static size_t f2fs_xattr_advise_list(const struct xattr_handler *handler,
struct dentry *dentry, char *list, size_t list_size,
const char *name, size_t len)
{
- const char *xname = F2FS_SYSTEM_ADVISE_PREFIX;
+ const char *xname = F2FS_SYSTEM_ADVISE_NAME;
size_t size;

size = strlen(xname) + 1;
@@ -129,9 +126,6 @@ static int f2fs_xattr_advise_get(const struct xattr_handler *handler,
{
struct inode *inode = d_inode(dentry);

- if (strcmp(name, "") != 0)
- return -EINVAL;
-
if (buffer)
*((char *)buffer) = F2FS_I(inode)->i_advise;
return sizeof(char);
@@ -143,8 +137,6 @@ static int f2fs_xattr_advise_set(const struct xattr_handler *handler,
{
struct inode *inode = d_inode(dentry);

- if (strcmp(name, "") != 0)
- return -EINVAL;
if (!inode_owner_or_capable(inode))
return -EPERM;
if (value == NULL)
@@ -197,7 +189,7 @@ const struct xattr_handler f2fs_xattr_trusted_handler = {
};

const struct xattr_handler f2fs_xattr_advise_handler = {
- .prefix = F2FS_SYSTEM_ADVISE_PREFIX,
+ .name = F2FS_SYSTEM_ADVISE_NAME,
.flags = F2FS_XATTR_INDEX_ADVISE,
.list = f2fs_xattr_advise_list,
.get = f2fs_xattr_advise_get,
diff --git a/fs/f2fs/xattr.h b/fs/f2fs/xattr.h
index 71a7100..79dccc8 100644
--- a/fs/f2fs/xattr.h
+++ b/fs/f2fs/xattr.h
@@ -27,7 +27,7 @@
#define F2FS_XATTR_REFCOUNT_MAX 1024

/* Name indexes */
-#define F2FS_SYSTEM_ADVISE_PREFIX "system.advise"
+#define F2FS_SYSTEM_ADVISE_NAME "system.advise"
#define F2FS_XATTR_INDEX_USER 1
#define F2FS_XATTR_INDEX_POSIX_ACL_ACCESS 2
#define F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT 3
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index e41a010..ab01530 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -431,9 +431,6 @@ int hfsplus_setxattr(struct dentry *dentry, const char *name,
char *xattr_name;
int res;

- if (!strcmp(name, ""))
- return -EINVAL;
-
xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
GFP_KERNEL);
if (!xattr_name)
@@ -589,9 +586,6 @@ ssize_t hfsplus_getxattr(struct dentry *dentry, const char *name,
int res;
char *xattr_name;

- if (!strcmp(name, ""))
- return -EINVAL;
-
xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
GFP_KERNEL);
if (!xattr_name)
@@ -853,9 +847,6 @@ static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (!strcmp(name, ""))
- return -EINVAL;
-
/*
* Don't allow retrieving properly prefixed attributes
* by prepending them with "osx."
@@ -876,9 +867,6 @@ static int hfsplus_osx_setxattr(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *buffer, size_t size, int flags)
{
- if (!strcmp(name, ""))
- return -EINVAL;
-
/*
* Don't allow setting properly prefixed attributes
* by prepending them with "osx."
diff --git a/fs/jffs2/security.c b/fs/jffs2/security.c
index bf12fe5..ea79932 100644
--- a/fs/jffs2/security.c
+++ b/fs/jffs2/security.c
@@ -52,9 +52,6 @@ static int jffs2_security_getxattr(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (!strcmp(name, ""))
- return -EINVAL;
-
return do_jffs2_getxattr(d_inode(dentry), JFFS2_XPREFIX_SECURITY,
name, buffer, size);
}
@@ -63,9 +60,6 @@ static int jffs2_security_setxattr(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *buffer, size_t size, int flags)
{
- if (!strcmp(name, ""))
- return -EINVAL;
-
return do_jffs2_setxattr(d_inode(dentry), JFFS2_XPREFIX_SECURITY,
name, buffer, size, flags);
}
diff --git a/fs/jffs2/xattr_trusted.c b/fs/jffs2/xattr_trusted.c
index a562da0..8b55fe4 100644
--- a/fs/jffs2/xattr_trusted.c
+++ b/fs/jffs2/xattr_trusted.c
@@ -20,8 +20,6 @@ static int jffs2_trusted_getxattr(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (!strcmp(name, ""))
- return -EINVAL;
return do_jffs2_getxattr(d_inode(dentry), JFFS2_XPREFIX_TRUSTED,
name, buffer, size);
}
@@ -30,8 +28,6 @@ static int jffs2_trusted_setxattr(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *buffer, size_t size, int flags)
{
- if (!strcmp(name, ""))
- return -EINVAL;
return do_jffs2_setxattr(d_inode(dentry), JFFS2_XPREFIX_TRUSTED,
name, buffer, size, flags);
}
diff --git a/fs/jffs2/xattr_user.c b/fs/jffs2/xattr_user.c
index cbc0472..b04335b 100644
--- a/fs/jffs2/xattr_user.c
+++ b/fs/jffs2/xattr_user.c
@@ -20,8 +20,6 @@ static int jffs2_user_getxattr(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (!strcmp(name, ""))
- return -EINVAL;
return do_jffs2_getxattr(d_inode(dentry), JFFS2_XPREFIX_USER,
name, buffer, size);
}
@@ -30,8 +28,6 @@ static int jffs2_user_setxattr(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *buffer, size_t size, int flags)
{
- if (!strcmp(name, ""))
- return -EINVAL;
return do_jffs2_setxattr(d_inode(dentry), JFFS2_XPREFIX_USER,
name, buffer, size, flags);
}
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 8981803..f6f40aa 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6253,9 +6253,6 @@ static int nfs4_xattr_set_nfs4_acl(const struct xattr_handler *handler,
const void *buf, size_t buflen,
int flags)
{
- if (strcmp(key, "") != 0)
- return -EINVAL;
-
return nfs4_proc_set_acl(d_inode(dentry), buf, buflen);
}

@@ -6263,9 +6260,6 @@ static int nfs4_xattr_get_nfs4_acl(const struct xattr_handler *handler,
struct dentry *dentry, const char *key,
void *buf, size_t buflen)
{
- if (strcmp(key, "") != 0)
- return -EINVAL;
-
return nfs4_proc_get_acl(d_inode(dentry), buf, buflen);
}

@@ -8834,7 +8828,7 @@ const struct nfs_rpc_ops nfs_v4_clientops = {
};

static const struct xattr_handler nfs4_xattr_nfs4_acl_handler = {
- .prefix = XATTR_NAME_NFSV4_ACL,
+ .name = XATTR_NAME_NFSV4_ACL,
.list = nfs4_xattr_list_nfs4_acl,
.get = nfs4_xattr_get_nfs4_acl,
.set = nfs4_xattr_set_nfs4_acl,
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index e9164f0..5823f98 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -544,8 +544,7 @@ static inline const char *ocfs2_xattr_prefix(int name_index)

if (name_index > 0 && name_index < OCFS2_XATTR_MAX)
handler = ocfs2_xattr_handler_map[name_index];
-
- return handler ? handler->prefix : NULL;
+ return handler ? xattr_prefix(handler) : NULL;
}

static u32 ocfs2_xattr_name_hash(struct inode *inode,
@@ -7249,8 +7248,6 @@ static int ocfs2_xattr_security_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ocfs2_xattr_get(d_inode(dentry), OCFS2_XATTR_INDEX_SECURITY,
name, buffer, size);
}
@@ -7259,9 +7256,6 @@ static int ocfs2_xattr_security_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
-
return ocfs2_xattr_set(d_inode(dentry), OCFS2_XATTR_INDEX_SECURITY,
name, value, size, flags);
}
@@ -7345,8 +7339,6 @@ static int ocfs2_xattr_trusted_get(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
return ocfs2_xattr_get(d_inode(dentry), OCFS2_XATTR_INDEX_TRUSTED,
name, buffer, size);
}
@@ -7355,9 +7347,6 @@ static int ocfs2_xattr_trusted_set(const struct xattr_handler *handler,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
- if (strcmp(name, "") == 0)
- return -EINVAL;
-
return ocfs2_xattr_set(d_inode(dentry), OCFS2_XATTR_INDEX_TRUSTED,
name, value, size, flags);
}
@@ -7398,8 +7387,6 @@ static int ocfs2_xattr_user_get(const struct xattr_handler *handler,
{
struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);

- if (strcmp(name, "") == 0)
- return -EINVAL;
if (osb->s_mount_opt & OCFS2_MOUNT_NOUSERXATTR)
return -EOPNOTSUPP;
return ocfs2_xattr_get(d_inode(dentry), OCFS2_XATTR_INDEX_USER, name,
@@ -7412,8 +7399,6 @@ static int ocfs2_xattr_user_set(const struct xattr_handler *handler,
{
struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);

- if (strcmp(name, "") == 0)
- return -EINVAL;
if (osb->s_mount_opt & OCFS2_MOUNT_NOUSERXATTR)
return -EOPNOTSUPP;

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 571465d..17efd76 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -769,8 +769,6 @@ posix_acl_xattr_get(const struct xattr_handler *handler,
struct posix_acl *acl;
int error;

- if (strcmp(name, "") != 0)
- return -EINVAL;
if (!IS_POSIXACL(d_backing_inode(dentry)))
return -EOPNOTSUPP;
if (d_is_symlink(dentry))
@@ -797,8 +795,6 @@ posix_acl_xattr_set(const struct xattr_handler *handler,
struct posix_acl *acl = NULL;
int ret;

- if (strcmp(name, "") != 0)
- return -EINVAL;
if (!IS_POSIXACL(inode))
return -EOPNOTSUPP;
if (!inode->i_op->set_acl)
@@ -832,7 +828,7 @@ posix_acl_xattr_list(const struct xattr_handler *handler,
struct dentry *dentry, char *list, size_t list_size,
const char *name, size_t name_len)
{
- const char *xname = handler->prefix;
+ const char *xname = handler->name;
size_t size;

if (!IS_POSIXACL(d_backing_inode(dentry)))
@@ -845,7 +841,7 @@ posix_acl_xattr_list(const struct xattr_handler *handler,
}

const struct xattr_handler posix_acl_access_xattr_handler = {
- .prefix = XATTR_NAME_POSIX_ACL_ACCESS,
+ .name = XATTR_NAME_POSIX_ACL_ACCESS,
.flags = ACL_TYPE_ACCESS,
.list = posix_acl_xattr_list,
.get = posix_acl_xattr_get,
@@ -854,7 +850,7 @@ const struct xattr_handler posix_acl_access_xattr_handler = {
EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);

const struct xattr_handler posix_acl_default_xattr_handler = {
- .prefix = XATTR_NAME_POSIX_ACL_DEFAULT,
+ .name = XATTR_NAME_POSIX_ACL_DEFAULT,
.flags = ACL_TYPE_DEFAULT,
.list = posix_acl_xattr_list,
.get = posix_acl_xattr_get,
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 66b26fd..efe2ed3 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -756,7 +756,8 @@ find_xattr_handler_prefix(const struct xattr_handler **handlers,
return NULL;

for_each_xattr_handler(handlers, xah) {
- if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0)
+ const char *prefix = xattr_prefix(xah);
+ if (strncmp(prefix, name, strlen(prefix)) == 0)
break;
}

diff --git a/fs/squashfs/xattr.c b/fs/squashfs/xattr.c
index 6a4cc34..2f0ccba 100644
--- a/fs/squashfs/xattr.c
+++ b/fs/squashfs/xattr.c
@@ -228,9 +228,6 @@ static int squashfs_xattr_handler_get(const struct xattr_handler *handler,
struct dentry *d, const char *name,
void *buffer, size_t size)
{
- if (name[0] == '\0')
- return -EINVAL;
-
return squashfs_xattr_get(d_inode(d), handler->flags, name,
buffer, size);
}
diff --git a/fs/xattr.c b/fs/xattr.c
index 58bdabc..418ad69 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -681,13 +681,20 @@ xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
return NULL;

for_each_xattr_handler(handlers, handler) {
- const char *n = strcmp_prefix(*name, handler->prefix);
+ const char *n;
+
+ n = strcmp_prefix(*name, xattr_prefix(handler));
if (n) {
+ if (!handler->prefix ^ !*n) {
+ if (*n)
+ continue;
+ return ERR_PTR(-EINVAL);
+ }
*name = n;
- break;
+ return handler;
}
}
- return handler;
+ return ERR_PTR(-EOPNOTSUPP);
}

/*
@@ -699,8 +706,8 @@ generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t s
const struct xattr_handler *handler;

handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
- if (!handler)
- return -EOPNOTSUPP;
+ if (IS_ERR(handler))
+ return PTR_ERR(handler);
return handler->get(handler, dentry, name, buffer, size);
}

@@ -746,8 +753,8 @@ generic_setxattr(struct dentry *dentry, const char *name, const void *value, siz
if (size == 0)
value = ""; /* empty EA, do not remove */
handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
- if (!handler)
- return -EOPNOTSUPP;
+ if (IS_ERR(handler))
+ return PTR_ERR(handler);
return handler->set(handler, dentry, name, value, size, flags);
}

@@ -761,8 +768,8 @@ generic_removexattr(struct dentry *dentry, const char *name)
const struct xattr_handler *handler;

handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
- if (!handler)
- return -EOPNOTSUPP;
+ if (IS_ERR(handler))
+ return PTR_ERR(handler);
return handler->set(handler, dentry, name, NULL, 0, XATTR_REPLACE);
}

@@ -789,7 +796,7 @@ EXPORT_SYMBOL(generic_removexattr);
const char *xattr_full_name(const struct xattr_handler *handler,
const char *name)
{
- size_t prefix_len = strlen(handler->prefix);
+ size_t prefix_len = strlen(xattr_prefix(handler));

return name - prefix_len;
}
diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
index 7288795..36a4385 100644
--- a/fs/xfs/xfs_xattr.c
+++ b/fs/xfs/xfs_xattr.c
@@ -39,9 +39,6 @@ xfs_xattr_get(const struct xattr_handler *handler, struct dentry *dentry,
struct xfs_inode *ip = XFS_I(d_inode(dentry));
int error, asize = size;

- if (strcmp(name, "") == 0)
- return -EINVAL;
-
/* Convert Linux syscall to XFS internal ATTR flags */
if (!size) {
xflags |= ATTR_KERNOVAL;
@@ -84,9 +81,6 @@ xfs_xattr_set(const struct xattr_handler *handler, struct dentry *dentry,
struct xfs_inode *ip = XFS_I(d_inode(dentry));
int error;

- if (strcmp(name, "") == 0)
- return -EINVAL;
-
/* Convert Linux syscall to XFS internal ATTR flags */
if (flags & XATTR_CREATE)
xflags |= ATTR_CREATE;
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index 45fa345..2d2d911 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -19,7 +19,13 @@
struct inode;
struct dentry;

+/*
+ * struct xattr_handler: When @name is set, match attributes with exactly that
+ * name. When @prefix is set instead, match attributes with that prefix and
+ * with a non-empty suffix.
+ */
struct xattr_handler {
+ const char *name;
const char *prefix;
int flags; /* fs private flags */
size_t (*list)(const struct xattr_handler *, struct dentry *dentry,
@@ -54,6 +60,11 @@ int generic_removexattr(struct dentry *dentry, const char *name);
ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
char **xattr_value, size_t size, gfp_t flags);

+static const char *xattr_prefix(const struct xattr_handler *handler)
+{
+ return handler->prefix ?: handler->name;
+}
+
struct simple_xattrs {
struct list_head head;
spinlock_t lock;
--
2.5.0

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