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https://gitlab.com/apparmor/apparmor.git
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98ee5a5741
When merging file entries in process_file_entries(), an error condition can leave the entries list in a bad state which can cause invalid reads and/or double frees when freeing the codomain and entries list memory. The problem comes from the need to sort the entries linked list. An array of pointers is created to represent the linked list, then the array is sorted, then the linked list and the array coexist while the entries are merged, then the linked list is reconstructed and the array is freed. While the entries are being merged, an error condition can occur and the function can return while the linked list is partially modified. The solution is to complete the sorting, reconstruct the linked list, and free the array immediately. Once the linked list is in a good state, the entries can be merged. Care is taken to adjust the linked list pointers as entries are merged. An error condition can occur but the linked list is always in a good state and proper cleanup can be performed without any memory access issues. Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Acked-by: Steve Beattie <steve@nxnw.org>
146 lines
3.4 KiB
C
146 lines
3.4 KiB
C
/*
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* Copyright (c) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
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* NOVELL (All rights reserved)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, contact Novell, Inc.
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*/
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#include <linux/unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <libintl.h>
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#define _(s) gettext(s)
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#include "parser.h"
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static int file_comp(const void *c1, const void *c2)
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{
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struct cod_entry **e1, **e2;
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e1 = (struct cod_entry **)c1;
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e2 = (struct cod_entry **)c2;
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int res = 0;
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//PERROR("strcmp %s %s\n", (*e1)->name, (*e2)->name);
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if ((*e1)->namespace) {
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if ((*e2)->namespace)
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res = strcmp((*e1)->namespace, (*e2)->namespace);
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else
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return 1;
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} else if ((*e2)->namespace) {
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return -1;
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}
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if (res)
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return res;
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if ((*e1)->link_name) {
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if ((*e2)->link_name)
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res = strcmp((*e1)->link_name, (*e2)->link_name);
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else
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return 1;
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} else if ((*e2)->link_name) {
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return -1;
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}
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if (res)
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return res;
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if ((*e1)->link_name)
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res = (*e2)->subset - (*e1)->subset;
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if (res)
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return res;
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if ((*e1)->deny != (*e2)->deny)
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return (*e1)->deny < (*e2)->deny ? -1 : 1;
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/* rules with ptrace and change_profile can only merge with
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* rules with exact same perm */
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if (((*e1)->mode & (AA_CHANGE_PROFILE | AA_PTRACE_PERMS)) !=
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((*e2)->mode & (AA_CHANGE_PROFILE | AA_PTRACE_PERMS)))
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return 1;
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return strcmp((*e1)->name, (*e2)->name);
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}
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static int process_file_entries(struct codomain *cod)
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{
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int n, count;
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struct cod_entry *flist, *cur, *next;
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struct cod_entry **table;
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for (flist = cod->entries, n = 0; flist; flist = flist->next)
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n++;
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count = n;
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if (count < 2)
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return 1;
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table = malloc(sizeof(struct cod_entry *) * (count + 1));
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if (!table) {
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PERROR(_("Couldn't merge entries. Out of Memory\n"));
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return 0;
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}
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n = 0;
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for (flist = cod->entries; flist; flist = flist->next) {
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table[n] = flist;
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n++;
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}
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qsort(table, count, sizeof(struct cod_entry *), file_comp);
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table[count] = NULL;
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for (n = 0; n < count; n++)
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table[n]->next = table[n + 1];
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cod->entries = table[0];
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free(table);
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/* walk the sorted table merging similar entries */
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for (cur = cod->entries, next = cur->next; next != NULL; next = cur->next) {
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if (file_comp(&cur, &next) == 0) {
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/* check for merged x consistency */
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if (!is_merged_x_consistent(cur->mode, next->mode)) {
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PERROR(_("profile %s: has merged rule %s with "
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"conflicting x modifiers\n"),
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cod->name, cur->name);
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return 0;
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}
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//if (next->audit)
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//fprintf(stderr, "warning: merging rule 0x%x %s\n", next->audit, next->name);
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cur->mode |= next->mode;
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cur->audit |= next->audit;
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cur->next = next->next;
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next->next = NULL;
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free_cod_entries(next);
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} else {
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cur = next;
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}
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}
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return 1;
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}
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int codomain_merge_rules(struct codomain *cod)
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{
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if (!process_file_entries(cod))
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goto fail;
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/* XXX return error from this */
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merge_hat_rules(cod);
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return 1;
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fail:
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return 0;
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}
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