xattr_security.c

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#include "reiserfs.h"
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/slab.h>
#include "xattr.h"
#include <linux/security.h>
#include <asm/uaccess.h>

static int
security_get(struct dentry *dentry, const char *name, void *buffer, size_t size,
        int handler_flags)
{
    if (strlen(name) < sizeof(XATTR_SECURITY_PREFIX))
        return -EINVAL;

    if (IS_PRIVATE(dentry->d_inode))
        return -EPERM;

    return reiserfs_xattr_get(dentry->d_inode, name, buffer, size);
}

static int
security_set(struct dentry *dentry, const char *name, const void *buffer,
         size_t size, int flags, int handler_flags)
{
    if (strlen(name) < sizeof(XATTR_SECURITY_PREFIX))
        return -EINVAL;

    if (IS_PRIVATE(dentry->d_inode))
        return -EPERM;

    return reiserfs_xattr_set(dentry->d_inode, name, buffer, size, flags);
}

static size_t security_list(struct dentry *dentry, char *list, size_t list_len,
                const char *name, size_t namelen, int handler_flags)
{
    const size_t len = namelen + 1;

    if (IS_PRIVATE(dentry->d_inode))
        return 0;

    if (list && len <= list_len) {
        memcpy(list, name, namelen);
        list[namelen] = '\0';
    }

    return len;
}

/* Initializes the security context for a new inode and returns the number
 * of blocks needed for the transaction. If successful, reiserfs_security
 * must be released using reiserfs_security_free when the caller is done. */
int reiserfs_security_init(struct inode *dir, struct inode *inode,
               const struct qstr *qstr,
               struct reiserfs_security_handle *sec)
{
    int blocks = 0;
    int error;

    sec->name = NULL;

    /* Don't add selinux attributes on xattrs - they'll never get used */
    if (IS_PRIVATE(dir))
        return 0;

    error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
                         &sec->value, &sec->length);
    if (error) {
        if (error == -EOPNOTSUPP)
            error = 0;

        sec->name = NULL;
        sec->value = NULL;
        sec->length = 0;
        return error;
    }

    if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
        blocks = reiserfs_xattr_jcreate_nblocks(inode) +
             reiserfs_xattr_nblocks(inode, sec->length);
        /* We don't want to count the directories twice if we have
         * a default ACL. */
        REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
    }
    return blocks;
}

int reiserfs_security_write(struct reiserfs_transaction_handle *th,
                struct inode *inode,
                struct reiserfs_security_handle *sec)
{
    int error;
    if (strlen(sec->name) < sizeof(XATTR_SECURITY_PREFIX))
        return -EINVAL;

    error = reiserfs_xattr_set_handle(th, inode, sec->name, sec->value,
                      sec->length, XATTR_CREATE);
    if (error == -ENODATA || error == -EOPNOTSUPP)
        error = 0;

    return error;
}

void reiserfs_security_free(struct reiserfs_security_handle *sec)
{
    kfree(sec->name);
    kfree(sec->value);
    sec->name = NULL;
    sec->value = NULL;
}

const struct xattr_handler reiserfs_xattr_security_handler = {
    .prefix = XATTR_SECURITY_PREFIX,
    .get = security_get,
    .set = security_set,
    .list = security_list,
};