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 #include "qemu/osdep.h"
  15 #include "9p.h"
  16 #include "fsdev/file-op-9p.h"
  17 #include "9p-xattr.h"
  18
  19
  20 static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
  21                                 const char *name, void *value, size_t size)
  22 {
  23     if (strncmp(name, "user.virtfs.", 12) == 0) {
  24         /*
  25          * Don't allow fetch of user.virtfs namesapce
  26          * in case of mapped security
  27          */
  28         errno = ENOATTR;
  29         return -1;
  30     }
  31     return local_getxattr_nofollow(ctx, path, name, value, size);
  32 }
  33
  34 static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
  35                                  char *name, void *value, size_t size)
  36 {
  37     int name_size = strlen(name) + 1;
  38     if (strncmp(name, "user.virtfs.", 12) == 0) {
  39
  40         /*  check if it is a mapped posix acl */
  41         if (strncmp(name, "user.virtfs.system.posix_acl_", 29) == 0) {
  42             /* adjust the name and size */
  43             name += 12;
  44             name_size -= 12;
  45         } else {
  46             /*
  47              * Don't allow fetch of user.virtfs namesapce
  48              * in case of mapped security
  49              */
  50             return 0;
  51         }
  52     }
  53     if (!value) {
  54         return name_size;
  55     }
  56
  57     if (size < name_size) {
  58         errno = ERANGE;
  59         return -1;
  60     }
  61
  62     /* name_size includes the trailing NUL. */
  63     memcpy(value, name, name_size);
  64     return name_size;
  65 }
  66
  67 static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name,
  68                             void *value, size_t size, int flags)
  69 {
  70     if (strncmp(name, "user.virtfs.", 12) == 0) {
  71         /*
  72          * Don't allow fetch of user.virtfs namesapce
  73          * in case of mapped security
  74          */
  75         errno = EACCES;
  76         return -1;
  77     }
  78     return local_setxattr_nofollow(ctx, path, name, value, size, flags);
  79 }
  80
  81 static int mp_user_removexattr(FsContext *ctx,
  82                                const char *path, const char *name)
  83 {
  84     if (strncmp(name, "user.virtfs.", 12) == 0) {
  85         /*
  86          * Don't allow fetch of user.virtfs namesapce
  87          * in case of mapped security
  88          */
  89         errno = EACCES;
  90         return -1;
  91     }
  92     return local_removexattr_nofollow(ctx, path, name);
  93 }
  94
  95 XattrOperations mapped_user_xattr = {
  96     .name = "user.",
  97     .getxattr = mp_user_getxattr,
  98     .setxattr = mp_user_setxattr,
  99     .listxattr = mp_user_listxattr,
 100     .removexattr = mp_user_removexattr,
 101 };
 102
 103 XattrOperations passthrough_user_xattr = {
 104     .name = "user.",
 105     .getxattr = pt_getxattr,
 106     .setxattr = pt_setxattr,
 107     .listxattr = pt_listxattr,
 108     .removexattr = pt_removexattr,
 109 };