cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
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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
     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};