LXR qemu/hw/9pfs/9p-xattr-user.c

   1/*
   2 * 9p user. xattr callback
   3 *
   4 * Copyright IBM, Corp. 2010
   5 *
   6 * Authors:
   7 * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2.  See
  10 * the COPYING file in the top-level directory.
  11 *
  12 */
  13
  14/*
  15 * Not so fast! You might want to read the 9p developer docs first:
  16 * https://wiki.qemu.org/Documentation/9p
  17 */
  18
  19#include "qemu/osdep.h"
  20#include "9p.h"
  21#include "fsdev/file-op-9p.h"
  22#include "9p-xattr.h"
  23
  24
  25static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
  26                                const char *name, void *value, size_t size)
  27{
  28    if (strncmp(name, "user.virtfs.", 12) == 0) {
  29        /*
  30         * Don't allow fetch of user.virtfs namesapce
  31         * in case of mapped security
  32         */
  33        errno = ENOATTR;
  34        return -1;
  35    }
  36    return local_getxattr_nofollow(ctx, path, name, value, size);
  37}
  38
  39static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
  40                                 char *name, void *value, size_t size)
  41{
  42    int name_size = strlen(name) + 1;
  43    if (strncmp(name, "user.virtfs.", 12) == 0) {
  44
  45        /*  check if it is a mapped posix acl */
  46        if (strncmp(name, "user.virtfs.system.posix_acl_", 29) == 0) {
  47            /* adjust the name and size */
  48            name += 12;
  49            name_size -= 12;
  50        } else {
  51            /*
  52             * Don't allow fetch of user.virtfs namesapce
  53             * in case of mapped security
  54             */
  55            return 0;
  56        }
  57    }
  58    if (!value) {
  59        return name_size;
  60    }
  61
  62    if (size < name_size) {
  63        errno = ERANGE;
  64        return -1;
  65    }
  66
  67    /* name_size includes the trailing NUL. */
  68    memcpy(value, name, name_size);
  69    return name_size;
  70}
  71
  72static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name,
  73                            void *value, size_t size, int flags)
  74{
  75    if (strncmp(name, "user.virtfs.", 12) == 0) {
  76        /*
  77         * Don't allow fetch of user.virtfs namesapce
  78         * in case of mapped security
  79         */
  80        errno = EACCES;
  81        return -1;
  82    }
  83    return local_setxattr_nofollow(ctx, path, name, value, size, flags);
  84}
  85
  86static int mp_user_removexattr(FsContext *ctx,
  87                               const char *path, const char *name)
  88{
  89    if (strncmp(name, "user.virtfs.", 12) == 0) {
  90        /*
  91         * Don't allow fetch of user.virtfs namesapce
  92         * in case of mapped security
  93         */
  94        errno = EACCES;
  95        return -1;
  96    }
  97    return local_removexattr_nofollow(ctx, path, name);
  98}
  99
 100XattrOperations mapped_user_xattr = {
 101    .name = "user.",
 102    .getxattr = mp_user_getxattr,
 103    .setxattr = mp_user_setxattr,
 104    .listxattr = mp_user_listxattr,
 105    .removexattr = mp_user_removexattr,
 106};
 107
 108XattrOperations passthrough_user_xattr = {
 109    .name = "user.",
 110    .getxattr = pt_getxattr,
 111    .setxattr = pt_setxattr,
 112    .listxattr = pt_listxattr,
 113    .removexattr = pt_removexattr,
 114};
 115