cd61f66935
and add some explanation for why there is use of linux namespaces in coolwsd itself Signed-off-by: Caolán McNamara <caolan.mcnamara@collabora.com> Change-Id: I5d5687cf095de1b7d5d978dcb6ad6a97f6e9c642
136 lines
2.9 KiB
C
136 lines
2.9 KiB
C
/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
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/*
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* Copyright the Collabora Online contributors.
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*
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* SPDX-License-Identifier: MPL-2.0
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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/*
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* Place for simple security-related code.
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*/
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#pragma once
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#ifdef __linux__
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#include <sys/capability.h>
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#endif
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#include <sys/types.h>
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#include <pwd.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdio.h>
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#ifndef COOL_USER_ID
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# error "include config.h for user id";
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#endif
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/*WARNING: PRIVILEGED CODE CHECKING START */
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inline int hasUID(const char *userId)
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{
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struct passwd *pw = getpwuid(getuid());
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if (pw && pw->pw_name && !strcmp(pw->pw_name, userId))
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return 1;
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return 0;
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}
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inline int isInContainer()
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{
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#ifdef __linux__
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FILE *cgroup;
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char line[80];
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const char *docker = ":/docker/";
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cgroup = fopen("/proc/self/cgroup", "r");
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if(!cgroup)
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{
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fprintf(stderr, "Error: cannot open /proc/self/cgroup\n");
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return 0;
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}
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while (fgets(line, sizeof(line), cgroup) != NULL)
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{
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if (strstr(line, docker) != NULL)
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{
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fclose(cgroup);
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return 1;
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}
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}
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fclose(cgroup);
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#endif
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return 0;
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}
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inline int hasCorrectUID([[maybe_unused]] const char* appName)
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{
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#if ENABLE_DEBUG
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return 1; // insecure but easy to use.
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#else
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if (hasUID(COOL_USER_ID))
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return 1;
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else {
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fprintf(stderr, "Security: %s incorrect user-name, other than '" COOL_USER_ID "'\n", appName);
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return 0;
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}
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#endif
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}
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/** Return 0 if no capability is set on the current binary. Positive number gives the bitfield of caps that are set, negative an error. */
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inline int hasAnyCapability()
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{
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#ifdef __linux__
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cap_t caps = cap_get_proc();
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if (caps == nullptr)
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{
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fprintf(stderr, "Error: cap_get_proc() failed.\n");
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return -1;
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}
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cap_t caps_none = cap_init();
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if (caps_none == nullptr)
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{
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fprintf(stderr, "Error: cap_init() failed.\n");
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cap_free(caps);
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return -1;
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}
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// 0 = caps of this process equal to no caps
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int result = cap_compare(caps, caps_none);
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cap_free(caps_none);
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cap_free(caps);
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return result;
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#else
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return 0;
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#endif
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}
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/** Drop all capabilities. return zero on success, negative on error. */
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inline int dropAllCapabilities()
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{
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#ifdef __linux__
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cap_t caps = cap_init();
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if (caps == nullptr)
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{
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fprintf(stderr, "Error: cap_init() failed.\n");
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return -1;
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}
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if (cap_set_proc(caps) == -1)
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{
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fprintf(stderr, "Error: cap_set_proc() failed.\n");
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return -1;
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}
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cap_free(caps);
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#endif
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return 0;
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}
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/*WARNING: PRIVILEGED CODE CHECKING END */
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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