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kernfs: implement "trusted.*" xattr support

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kernfs inherited "security.*" xattr support from sysfs.  This patch
extends xattr support to "trusted.*" using simple_xattr_*().  As
trusted xattrs are restricted to CAP_SYS_ADMIN, simple_xattr_*() which
uses kernel memory for storage shouldn't be problematic.

Note that the existing "security.*" support doesn't implement
get/remove/list and the this patch only implements those ops for
"trusted.*".  We probably want to extend those ops to include support
for "security.*".

This patch will allow using kernfs from cgroup which requires
"trusted.*" xattr support.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David P. Quigley <dpquigl@tycho.nsa.gov>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tejun Heo
2013-11-23 17:40:02 -05:00
committed by Greg Kroah-Hartman
parent 9a8049affd
commit 2322392b02
4 changed files with 74 additions and 11 deletions
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63
fs/kernfs/inode.c
View File

@@ -35,6 +35,9 @@ static const struct inode_operations sysfs_inode_operations = {
.setattr = sysfs_setattr,
.getattr = sysfs_getattr,
.setxattr = sysfs_setxattr,
.removexattr = sysfs_removexattr,
.getxattr = sysfs_getxattr,
.listxattr = sysfs_listxattr,
};
void __init sysfs_inode_init(void)
@@ -61,6 +64,8 @@ static struct sysfs_inode_attrs *sysfs_inode_attrs(struct sysfs_dirent *sd)
iattrs->ia_gid = GLOBAL_ROOT_GID;
iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
simple_xattrs_init(&sd->s_iattr->xattrs);
return sd->s_iattr;
}
@@ -162,23 +167,25 @@ int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags)
{
struct sysfs_dirent *sd = dentry->d_fsdata;
struct sysfs_inode_attrs *attrs;
void *secdata;
int error;
u32 secdata_len = 0;
if (!sd)
return -EINVAL;
attrs = sysfs_inode_attrs(sd);
if (!attrs)
return -ENOMEM;
if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
error = security_inode_setsecurity(dentry->d_inode, suffix,
value, size, flags);
if (error)
goto out;
return error;
error = security_inode_getsecctx(dentry->d_inode,
&secdata, &secdata_len);
if (error)
goto out;
return error;
mutex_lock(&sysfs_mutex);
error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len);
@@ -186,10 +193,50 @@ int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
if (secdata)
security_release_secctx(secdata, secdata_len);
} else
return -EINVAL;
out:
return error;
return error;
} else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
return simple_xattr_set(&attrs->xattrs, name, value, size,
flags);
}
return -EINVAL;
}
int sysfs_removexattr(struct dentry *dentry, const char *name)
{
struct sysfs_dirent *sd = dentry->d_fsdata;
struct sysfs_inode_attrs *attrs;
attrs = sysfs_inode_attrs(sd);
if (!attrs)
return -ENOMEM;
return simple_xattr_remove(&attrs->xattrs, name);
}
ssize_t sysfs_getxattr(struct dentry *dentry, const char *name, void *buf,
size_t size)
{
struct sysfs_dirent *sd = dentry->d_fsdata;
struct sysfs_inode_attrs *attrs;
attrs = sysfs_inode_attrs(sd);
if (!attrs)
return -ENOMEM;
return simple_xattr_get(&attrs->xattrs, name, buf, size);
}
ssize_t sysfs_listxattr(struct dentry *dentry, char *buf, size_t size)
{
struct sysfs_dirent *sd = dentry->d_fsdata;
struct sysfs_inode_attrs *attrs;
attrs = sysfs_inode_attrs(sd);
if (!attrs)
return -ENOMEM;
return simple_xattr_list(&attrs->xattrs, buf, size);
}
static inline void set_default_inode_attr(struct inode *inode, umode_t mode)