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
  25 static 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
  39 static 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
  72 static 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
  86 static 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
 100 XattrOperations 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
 108 XattrOperations passthrough_user_xattr = {
 109     .name = "user.",
 110     .getxattr = pt_getxattr,
 111     .setxattr = pt_setxattr,
 112     .listxattr = pt_listxattr,
 113     .removexattr = pt_removexattr,
 114 };