| Backport patch to fix CVE-2021-3621. |
| |
| Upstream-Status: Backport [https://github.com/SSSD/sssd/commit/7ab83f9] |
| CVE: CVE-2021-3621 |
| |
| Signed-off-by: Kai Kang <kai.kang@windriver.com> |
| |
| From 7ab83f97e1cbefb78ece17232185bdd2985f0bbe Mon Sep 17 00:00:00 2001 |
| From: Alexey Tikhonov <atikhono@redhat.com> |
| Date: Fri, 18 Jun 2021 13:17:19 +0200 |
| Subject: [PATCH] TOOLS: replace system() with execvp() to avoid execution of |
| user supplied command |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| :relnote: A flaw was found in SSSD, where the sssctl command was |
| vulnerable to shell command injection via the logs-fetch and |
| cache-expire subcommands. This flaw allows an attacker to trick |
| the root user into running a specially crafted sssctl command, |
| such as via sudo, to gain root access. The highest threat from this |
| vulnerability is to confidentiality, integrity, as well as system |
| availability. |
| This patch fixes a flaw by replacing system() with execvp(). |
| |
| :fixes: CVE-2021-3621 |
| |
| Reviewed-by: Pavel Březina <pbrezina@redhat.com> |
| --- |
| src/tools/sssctl/sssctl.c | 39 ++++++++++++++++------- |
| src/tools/sssctl/sssctl.h | 2 +- |
| src/tools/sssctl/sssctl_data.c | 57 +++++++++++----------------------- |
| src/tools/sssctl/sssctl_logs.c | 32 +++++++++++++++---- |
| 4 files changed, 73 insertions(+), 57 deletions(-) |
| |
| diff --git a/src/tools/sssctl/sssctl.c b/src/tools/sssctl/sssctl.c |
| index 2997dbf968..8adaf30910 100644 |
| --- a/src/tools/sssctl/sssctl.c |
| +++ b/src/tools/sssctl/sssctl.c |
| @@ -97,22 +97,36 @@ sssctl_prompt(const char *message, |
| return SSSCTL_PROMPT_ERROR; |
| } |
| |
| -errno_t sssctl_run_command(const char *command) |
| +errno_t sssctl_run_command(const char *const argv[]) |
| { |
| int ret; |
| + int wstatus; |
| |
| - DEBUG(SSSDBG_TRACE_FUNC, "Running %s\n", command); |
| + DEBUG(SSSDBG_TRACE_FUNC, "Running '%s'\n", argv[0]); |
| |
| - ret = system(command); |
| + ret = fork(); |
| if (ret == -1) { |
| - DEBUG(SSSDBG_CRIT_FAILURE, "Unable to execute %s\n", command); |
| ERROR("Error while executing external command\n"); |
| return EFAULT; |
| - } else if (WEXITSTATUS(ret) != 0) { |
| - DEBUG(SSSDBG_CRIT_FAILURE, "Command %s failed with [%d]\n", |
| - command, WEXITSTATUS(ret)); |
| + } |
| + |
| + if (ret == 0) { |
| + /* cast is safe - see |
| + https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html |
| + "The statement about argv[] and envp[] being constants ... " |
| + */ |
| + execvp(argv[0], discard_const_p(char * const, argv)); |
| ERROR("Error while executing external command\n"); |
| - return EIO; |
| + _exit(1); |
| + } else { |
| + if (waitpid(ret, &wstatus, 0) == -1) { |
| + ERROR("Error while executing external command '%s'\n", argv[0]); |
| + return EFAULT; |
| + } else if (WEXITSTATUS(wstatus) != 0) { |
| + ERROR("Command '%s' failed with [%d]\n", |
| + argv[0], WEXITSTATUS(wstatus)); |
| + return EIO; |
| + } |
| } |
| |
| return EOK; |
| @@ -132,11 +146,14 @@ static errno_t sssctl_manage_service(enum sssctl_svc_action action) |
| #elif defined(HAVE_SERVICE) |
| switch (action) { |
| case SSSCTL_SVC_START: |
| - return sssctl_run_command(SERVICE_PATH" sssd start"); |
| + return sssctl_run_command( |
| + (const char *[]){SERVICE_PATH, "sssd", "start", NULL}); |
| case SSSCTL_SVC_STOP: |
| - return sssctl_run_command(SERVICE_PATH" sssd stop"); |
| + return sssctl_run_command( |
| + (const char *[]){SERVICE_PATH, "sssd", "stop", NULL}); |
| case SSSCTL_SVC_RESTART: |
| - return sssctl_run_command(SERVICE_PATH" sssd restart"); |
| + return sssctl_run_command( |
| + (const char *[]){SERVICE_PATH, "sssd", "restart", NULL}); |
| } |
| #endif |
| |
| diff --git a/src/tools/sssctl/sssctl.h b/src/tools/sssctl/sssctl.h |
| index 0115b2457c..599ef65196 100644 |
| --- a/src/tools/sssctl/sssctl.h |
| +++ b/src/tools/sssctl/sssctl.h |
| @@ -47,7 +47,7 @@ enum sssctl_prompt_result |
| sssctl_prompt(const char *message, |
| enum sssctl_prompt_result defval); |
| |
| -errno_t sssctl_run_command(const char *command); |
| +errno_t sssctl_run_command(const char *const argv[]); /* argv[0] - command */ |
| bool sssctl_start_sssd(bool force); |
| bool sssctl_stop_sssd(bool force); |
| bool sssctl_restart_sssd(bool force); |
| diff --git a/src/tools/sssctl/sssctl_data.c b/src/tools/sssctl/sssctl_data.c |
| index 8d79b977fd..bf22913416 100644 |
| --- a/src/tools/sssctl/sssctl_data.c |
| +++ b/src/tools/sssctl/sssctl_data.c |
| @@ -105,15 +105,15 @@ static errno_t sssctl_backup(bool force) |
| } |
| } |
| |
| - ret = sssctl_run_command("sss_override user-export " |
| - SSS_BACKUP_USER_OVERRIDES); |
| + ret = sssctl_run_command((const char *[]){"sss_override", "user-export", |
| + SSS_BACKUP_USER_OVERRIDES, NULL}); |
| if (ret != EOK) { |
| ERROR("Unable to export user overrides\n"); |
| return ret; |
| } |
| |
| - ret = sssctl_run_command("sss_override group-export " |
| - SSS_BACKUP_GROUP_OVERRIDES); |
| + ret = sssctl_run_command((const char *[]){"sss_override", "group-export", |
| + SSS_BACKUP_GROUP_OVERRIDES, NULL}); |
| if (ret != EOK) { |
| ERROR("Unable to export group overrides\n"); |
| return ret; |
| @@ -158,8 +158,8 @@ static errno_t sssctl_restore(bool force_start, bool force_restart) |
| } |
| |
| if (sssctl_backup_file_exists(SSS_BACKUP_USER_OVERRIDES)) { |
| - ret = sssctl_run_command("sss_override user-import " |
| - SSS_BACKUP_USER_OVERRIDES); |
| + ret = sssctl_run_command((const char *[]){"sss_override", "user-import", |
| + SSS_BACKUP_USER_OVERRIDES, NULL}); |
| if (ret != EOK) { |
| ERROR("Unable to import user overrides\n"); |
| return ret; |
| @@ -167,8 +167,8 @@ static errno_t sssctl_restore(bool force_start, bool force_restart) |
| } |
| |
| if (sssctl_backup_file_exists(SSS_BACKUP_USER_OVERRIDES)) { |
| - ret = sssctl_run_command("sss_override group-import " |
| - SSS_BACKUP_GROUP_OVERRIDES); |
| + ret = sssctl_run_command((const char *[]){"sss_override", "group-import", |
| + SSS_BACKUP_GROUP_OVERRIDES, NULL}); |
| if (ret != EOK) { |
| ERROR("Unable to import group overrides\n"); |
| return ret; |
| @@ -296,40 +296,19 @@ errno_t sssctl_cache_expire(struct sss_cmdline *cmdline, |
| void *pvt) |
| { |
| errno_t ret; |
| - char *cmd_args = NULL; |
| - const char *cachecmd = SSS_CACHE; |
| - char *cmd = NULL; |
| - int i; |
| - |
| - if (cmdline->argc == 0) { |
| - ret = sssctl_run_command(cachecmd); |
| - goto done; |
| - } |
| |
| - cmd_args = talloc_strdup(tool_ctx, ""); |
| - if (cmd_args == NULL) { |
| - ret = ENOMEM; |
| - goto done; |
| + const char **args = talloc_array_size(tool_ctx, |
| + sizeof(char *), |
| + cmdline->argc + 2); |
| + if (!args) { |
| + return ENOMEM; |
| } |
| + memcpy(&args[1], cmdline->argv, sizeof(char *) * cmdline->argc); |
| + args[0] = SSS_CACHE; |
| + args[cmdline->argc + 1] = NULL; |
| |
| - for (i = 0; i < cmdline->argc; i++) { |
| - cmd_args = talloc_strdup_append(cmd_args, cmdline->argv[i]); |
| - if (i != cmdline->argc - 1) { |
| - cmd_args = talloc_strdup_append(cmd_args, " "); |
| - } |
| - } |
| - |
| - cmd = talloc_asprintf(tool_ctx, "%s %s", cachecmd, cmd_args); |
| - if (cmd == NULL) { |
| - ret = ENOMEM; |
| - goto done; |
| - } |
| - |
| - ret = sssctl_run_command(cmd); |
| - |
| -done: |
| - talloc_free(cmd_args); |
| - talloc_free(cmd); |
| + ret = sssctl_run_command(args); |
| |
| + talloc_free(args); |
| return ret; |
| } |
| diff --git a/src/tools/sssctl/sssctl_logs.c b/src/tools/sssctl/sssctl_logs.c |
| index 9ff2be05b6..ebb2c4571c 100644 |
| --- a/src/tools/sssctl/sssctl_logs.c |
| +++ b/src/tools/sssctl/sssctl_logs.c |
| @@ -31,6 +31,7 @@ |
| #include <ldb.h> |
| #include <popt.h> |
| #include <stdio.h> |
| +#include <glob.h> |
| |
| #include "util/util.h" |
| #include "tools/common/sss_process.h" |
| @@ -230,6 +231,7 @@ errno_t sssctl_logs_remove(struct sss_cmdline *cmdline, |
| { |
| struct sssctl_logs_opts opts = {0}; |
| errno_t ret; |
| + glob_t globbuf; |
| |
| /* Parse command line. */ |
| struct poptOption options[] = { |
| @@ -253,8 +255,20 @@ errno_t sssctl_logs_remove(struct sss_cmdline *cmdline, |
| |
| sss_signal(SIGHUP); |
| } else { |
| + globbuf.gl_offs = 4; |
| + ret = glob(LOG_PATH"/*.log", GLOB_ERR|GLOB_DOOFFS, NULL, &globbuf); |
| + if (ret != 0) { |
| + DEBUG(SSSDBG_CRIT_FAILURE, "Unable to expand log files list\n"); |
| + return ret; |
| + } |
| + globbuf.gl_pathv[0] = discard_const_p(char, "truncate"); |
| + globbuf.gl_pathv[1] = discard_const_p(char, "--no-create"); |
| + globbuf.gl_pathv[2] = discard_const_p(char, "--size"); |
| + globbuf.gl_pathv[3] = discard_const_p(char, "0"); |
| + |
| PRINT("Truncating log files...\n"); |
| - ret = sssctl_run_command("truncate --no-create --size 0 " LOG_FILES); |
| + ret = sssctl_run_command((const char * const*)globbuf.gl_pathv); |
| + globfree(&globbuf); |
| if (ret != EOK) { |
| ERROR("Unable to truncate log files\n"); |
| return ret; |
| @@ -269,8 +283,8 @@ errno_t sssctl_logs_fetch(struct sss_cmdline *cmdline, |
| void *pvt) |
| { |
| const char *file; |
| - const char *cmd; |
| errno_t ret; |
| + glob_t globbuf; |
| |
| /* Parse command line. */ |
| ret = sss_tool_popt_ex(cmdline, NULL, SSS_TOOL_OPT_OPTIONAL, NULL, NULL, |
| @@ -280,13 +294,19 @@ errno_t sssctl_logs_fetch(struct sss_cmdline *cmdline, |
| return ret; |
| } |
| |
| - cmd = talloc_asprintf(tool_ctx, "tar -czf %s %s", file, LOG_FILES); |
| - if (cmd == NULL) { |
| - ERROR("Out of memory!"); |
| + globbuf.gl_offs = 3; |
| + ret = glob(LOG_PATH"/*.log", GLOB_ERR|GLOB_DOOFFS, NULL, &globbuf); |
| + if (ret != 0) { |
| + DEBUG(SSSDBG_CRIT_FAILURE, "Unable to expand log files list\n"); |
| + return ret; |
| } |
| + globbuf.gl_pathv[0] = discard_const_p(char, "tar"); |
| + globbuf.gl_pathv[1] = discard_const_p(char, "-czf"); |
| + globbuf.gl_pathv[2] = discard_const_p(char, file); |
| |
| PRINT("Archiving log files into %s...\n", file); |
| - ret = sssctl_run_command(cmd); |
| + ret = sssctl_run_command((const char * const*)globbuf.gl_pathv); |
| + globfree(&globbuf); |
| if (ret != EOK) { |
| ERROR("Unable to archive log files\n"); |
| return ret; |