qemu

FORK: QEMU emulator
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9p-xattr-user.c (2995B)

      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 namespace
     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 namespace
     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 namespace
     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 namespace
     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 };