cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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procattr.c (3527B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * AppArmor security module
      4 *
      5 * This file contains AppArmor /proc/<pid>/attr/ interface functions
      6 *
      7 * Copyright (C) 1998-2008 Novell/SUSE
      8 * Copyright 2009-2010 Canonical Ltd.
      9 */
     10
     11#include "include/apparmor.h"
     12#include "include/cred.h"
     13#include "include/policy.h"
     14#include "include/policy_ns.h"
     15#include "include/domain.h"
     16#include "include/procattr.h"
     17
     18
     19/**
     20 * aa_getprocattr - Return the profile information for @profile
     21 * @profile: the profile to print profile info about  (NOT NULL)
     22 * @string: Returns - string containing the profile info (NOT NULL)
     23 *
     24 * Requires: profile != NULL
     25 *
     26 * Creates a string containing the namespace_name://profile_name for
     27 * @profile.
     28 *
     29 * Returns: size of string placed in @string else error code on failure
     30 */
     31int aa_getprocattr(struct aa_label *label, char **string)
     32{
     33	struct aa_ns *ns = labels_ns(label);
     34	struct aa_ns *current_ns = aa_get_current_ns();
     35	int len;
     36
     37	if (!aa_ns_visible(current_ns, ns, true)) {
     38		aa_put_ns(current_ns);
     39		return -EACCES;
     40	}
     41
     42	len = aa_label_snxprint(NULL, 0, current_ns, label,
     43				FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
     44				FLAG_HIDDEN_UNCONFINED);
     45	AA_BUG(len < 0);
     46
     47	*string = kmalloc(len + 2, GFP_KERNEL);
     48	if (!*string) {
     49		aa_put_ns(current_ns);
     50		return -ENOMEM;
     51	}
     52
     53	len = aa_label_snxprint(*string, len + 2, current_ns, label,
     54				FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
     55				FLAG_HIDDEN_UNCONFINED);
     56	if (len < 0) {
     57		aa_put_ns(current_ns);
     58		return len;
     59	}
     60
     61	(*string)[len] = '\n';
     62	(*string)[len + 1] = 0;
     63
     64	aa_put_ns(current_ns);
     65	return len + 1;
     66}
     67
     68/**
     69 * split_token_from_name - separate a string of form  <token>^<name>
     70 * @op: operation being checked
     71 * @args: string to parse  (NOT NULL)
     72 * @token: stores returned parsed token value  (NOT NULL)
     73 *
     74 * Returns: start position of name after token else NULL on failure
     75 */
     76static char *split_token_from_name(const char *op, char *args, u64 *token)
     77{
     78	char *name;
     79
     80	*token = simple_strtoull(args, &name, 16);
     81	if ((name == args) || *name != '^') {
     82		AA_ERROR("%s: Invalid input '%s'", op, args);
     83		return ERR_PTR(-EINVAL);
     84	}
     85
     86	name++;			/* skip ^ */
     87	if (!*name)
     88		name = NULL;
     89	return name;
     90}
     91
     92/**
     93 * aa_setprocattr_chagnehat - handle procattr interface to change_hat
     94 * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
     95 * @size: size of the args
     96 * @flags: set of flags governing behavior
     97 *
     98 * Returns: %0 or error code if change_hat fails
     99 */
    100int aa_setprocattr_changehat(char *args, size_t size, int flags)
    101{
    102	char *hat;
    103	u64 token;
    104	const char *hats[16];		/* current hard limit on # of names */
    105	int count = 0;
    106
    107	hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
    108	if (IS_ERR(hat))
    109		return PTR_ERR(hat);
    110
    111	if (!hat && !token) {
    112		AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
    113		return -EINVAL;
    114	}
    115
    116	if (hat) {
    117		/* set up hat name vector, args guaranteed null terminated
    118		 * at args[size] by setprocattr.
    119		 *
    120		 * If there are multiple hat names in the buffer each is
    121		 * separated by a \0.  Ie. userspace writes them pre tokenized
    122		 */
    123		char *end = args + size;
    124		for (count = 0; (hat < end) && count < 16; ++count) {
    125			char *next = hat + strlen(hat) + 1;
    126			hats[count] = hat;
    127			AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
    128				 , __func__, current->pid, token, count, hat);
    129			hat = next;
    130		}
    131	} else
    132		AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
    133			 __func__, current->pid, token, count, "<NULL>");
    134
    135	return aa_change_hat(hats, count, token, flags);
    136}