hw/9pfs/9p-posix-acl.c

   1 /*
   2  * 9p system.posix* 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 "qemu/xattr.h"
  21 #include "9p.h"
  22 #include "fsdev/file-op-9p.h"
  23 #include "9p-xattr.h"
  24
  25 #define MAP_ACL_ACCESS "user.virtfs.system.posix_acl_access"
  26 #define MAP_ACL_DEFAULT "user.virtfs.system.posix_acl_default"
  27 #define ACL_ACCESS "system.posix_acl_access"
  28 #define ACL_DEFAULT "system.posix_acl_default"
  29
  30 static ssize_t mp_pacl_getxattr(FsContext *ctx, const char *path,
  31                                 const char *name, void *value, size_t size)
  32 {
  33     return local_getxattr_nofollow(ctx, path, MAP_ACL_ACCESS, value, size);
  34 }
  35
  36 static ssize_t mp_pacl_listxattr(FsContext *ctx, const char *path,
  37                                  char *name, void *value, size_t osize)
  38 {
  39     ssize_t len = sizeof(ACL_ACCESS);
  40
  41     if (!value) {
  42         return len;
  43     }
  44
  45     if (osize < len) {
  46         errno = ERANGE;
  47         return -1;
  48     }
  49
  50     /* len includes the trailing NUL */
  51     memcpy(value, ACL_ACCESS, len);
  52     return 0;
  53 }
  54
  55 static int mp_pacl_setxattr(FsContext *ctx, const char *path, const char *name,
  56                             void *value, size_t size, int flags)
  57 {
  58     return local_setxattr_nofollow(ctx, path, MAP_ACL_ACCESS, value, size,
  59                                    flags);
  60 }
  61
  62 static int mp_pacl_removexattr(FsContext *ctx,
  63                                const char *path, const char *name)
  64 {
  65     int ret;
  66
  67     ret = local_removexattr_nofollow(ctx, path, MAP_ACL_ACCESS);
  68     if (ret == -1 && errno == ENODATA) {
  69         /*
  70          * We don't get ENODATA error when trying to remove a
  71          * posix acl that is not present. So don't throw the error
  72          * even in case of mapped security model
  73          */
  74         errno = 0;
  75         ret = 0;
  76     }
  77     return ret;
  78 }
  79
  80 static ssize_t mp_dacl_getxattr(FsContext *ctx, const char *path,
  81                                 const char *name, void *value, size_t size)
  82 {
  83     return local_getxattr_nofollow(ctx, path, MAP_ACL_DEFAULT, value, size);
  84 }
  85
  86 static ssize_t mp_dacl_listxattr(FsContext *ctx, const char *path,
  87                                  char *name, void *value, size_t osize)
  88 {
  89     ssize_t len = sizeof(ACL_DEFAULT);
  90
  91     if (!value) {
  92         return len;
  93     }
  94
  95     if (osize < len) {
  96         errno = ERANGE;
  97         return -1;
  98     }
  99
 100     /* len includes the trailing NUL */
 101     memcpy(value, ACL_DEFAULT, len);
 102     return 0;
 103 }
 104
 105 static int mp_dacl_setxattr(FsContext *ctx, const char *path, const char *name,
 106                             void *value, size_t size, int flags)
 107 {
 108     return local_setxattr_nofollow(ctx, path, MAP_ACL_DEFAULT, value, size,
 109                                    flags);
 110 }
 111
 112 static int mp_dacl_removexattr(FsContext *ctx,
 113                                const char *path, const char *name)
 114 {
 115     int ret;
 116
 117     ret = local_removexattr_nofollow(ctx, path, MAP_ACL_DEFAULT);
 118     if (ret == -1 && errno == ENODATA) {
 119         /*
 120          * We don't get ENODATA error when trying to remove a
 121          * posix acl that is not present. So don't throw the error
 122          * even in case of mapped security model
 123          */
 124         errno = 0;
 125         ret = 0;
 126     }
 127     return ret;
 128 }
 129
 130
 131 XattrOperations mapped_pacl_xattr = {
 132     .name = "system.posix_acl_access",
 133     .getxattr = mp_pacl_getxattr,
 134     .setxattr = mp_pacl_setxattr,
 135     .listxattr = mp_pacl_listxattr,
 136     .removexattr = mp_pacl_removexattr,
 137 };
 138
 139 XattrOperations mapped_dacl_xattr = {
 140     .name = "system.posix_acl_default",
 141     .getxattr = mp_dacl_getxattr,
 142     .setxattr = mp_dacl_setxattr,
 143     .listxattr = mp_dacl_listxattr,
 144     .removexattr = mp_dacl_removexattr,
 145 };
 146
 147 XattrOperations passthrough_acl_xattr = {
 148     .name = "system.posix_acl_",
 149     .getxattr = pt_getxattr,
 150     .setxattr = pt_setxattr,
 151     .listxattr = pt_listxattr,
 152     .removexattr = pt_removexattr,
 153 };
 154
 155 XattrOperations none_acl_xattr = {
 156     .name = "system.posix_acl_",
 157     .getxattr = notsup_getxattr,
 158     .setxattr = notsup_setxattr,
 159     .listxattr = notsup_listxattr,
 160     .removexattr = notsup_removexattr,
 161 };