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@@ -0,0 +1,277 @@
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+ From 5a9a2f53ff44b1bd25a6de7c4ba91c709b63b0ba Mon Sep 17 00:00:00 2001
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+ From: Alexey Tikhonov <atikhono@redhat.com>
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+ Date: Fri, 18 Jun 2021 13:17:19 +0200
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+ Subject: [PATCH] TOOLS: replace system() with execvp() to avoid execution of
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+ user supplied command
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+
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+ A flaw was found in SSSD, where the sssctl command was vulnerable
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+ to shell command injection via the logs-fetch and cache-expire
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+ subcommands. This flaw allows an attacker to trick the root user
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+ into running a specially crafted sssctl command, such as via sudo,
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+ to gain root access. The highest threat from this vulnerability is
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+ to confidentiality, integrity, as well as system availability.
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+
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+ :fixes: CVE-2021-3621
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+ ---
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+ src/tools/sssctl/sssctl.c | 39 ++++++++++++++++-------
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+ src/tools/sssctl/sssctl.h | 2 +-
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+ src/tools/sssctl/sssctl_data.c | 57 +++++++++++-----------------------
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+ src/tools/sssctl/sssctl_logs.c | 32 +++++++++++++++----
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+ 4 files changed, 73 insertions(+), 57 deletions(-)
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+
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+ diff --git a/src/tools/sssctl/sssctl.c b/src/tools/sssctl/sssctl.c
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+ index 2997dbf968acdd0b9821f726414f8ae1cf34b5d8..8adaf30910e13ea9e7c8ab8b151920c4f307427b 100644
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+ --- a/src/tools/sssctl/sssctl.c
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+ +++ b/src/tools/sssctl/sssctl.c
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+ @@ -97,22 +97,36 @@ sssctl_prompt(const char *message,
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+ return SSSCTL_PROMPT_ERROR;
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+ }
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+
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+ -errno_t sssctl_run_command(const char *command)
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+ +errno_t sssctl_run_command(const char *const argv[])
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+ {
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+ int ret;
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+ + int wstatus;
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+
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+ - DEBUG(SSSDBG_TRACE_FUNC, "Running %s\n", command);
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+ + DEBUG(SSSDBG_TRACE_FUNC, "Running '%s'\n", argv[0]);
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+
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+ - ret = system(command);
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+ + ret = fork();
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+ if (ret == -1) {
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+ - DEBUG(SSSDBG_CRIT_FAILURE, "Unable to execute %s\n", command);
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+ ERROR("Error while executing external command\n");
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+ return EFAULT;
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+ - } else if (WEXITSTATUS(ret) != 0) {
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+ - DEBUG(SSSDBG_CRIT_FAILURE, "Command %s failed with [%d]\n",
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+ - command, WEXITSTATUS(ret));
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+ + }
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+ +
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+ + if (ret == 0) {
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+ + /* cast is safe - see
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+ + https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html
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+ + "The statement about argv[] and envp[] being constants ... "
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+ + */
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+ + execvp(argv[0], discard_const_p(char * const, argv));
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+ ERROR("Error while executing external command\n");
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+ - return EIO;
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+ + _exit(1);
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+ + } else {
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+ + if (waitpid(ret, &wstatus, 0) == -1) {
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+ + ERROR("Error while executing external command '%s'\n", argv[0]);
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+ + return EFAULT;
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+ + } else if (WEXITSTATUS(wstatus) != 0) {
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+ + ERROR("Command '%s' failed with [%d]\n",
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+ + argv[0], WEXITSTATUS(wstatus));
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+ + return EIO;
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+ + }
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+ }
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+
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+ return EOK;
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+ @@ -132,11 +146,14 @@ static errno_t sssctl_manage_service(enum sssctl_svc_action action)
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+ #elif defined(HAVE_SERVICE)
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+ switch (action) {
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+ case SSSCTL_SVC_START:
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+ - return sssctl_run_command(SERVICE_PATH" sssd start");
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+ + return sssctl_run_command(
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+ + (const char *[]){SERVICE_PATH, "sssd", "start", NULL});
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+ case SSSCTL_SVC_STOP:
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+ - return sssctl_run_command(SERVICE_PATH" sssd stop");
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+ + return sssctl_run_command(
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+ + (const char *[]){SERVICE_PATH, "sssd", "stop", NULL});
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+ case SSSCTL_SVC_RESTART:
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+ - return sssctl_run_command(SERVICE_PATH" sssd restart");
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+ + return sssctl_run_command(
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+ + (const char *[]){SERVICE_PATH, "sssd", "restart", NULL});
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+ }
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+ #endif
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+
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+ diff --git a/src/tools/sssctl/sssctl.h b/src/tools/sssctl/sssctl.h
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+ index 0115b2457c48bb0b8ad8ef8fd20d6fc81bdb58b4..599ef65196fcae6454cd5b46aa7a2cf6e7cbba73 100644
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+ --- a/src/tools/sssctl/sssctl.h
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+ +++ b/src/tools/sssctl/sssctl.h
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+ @@ -47,7 +47,7 @@ enum sssctl_prompt_result
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+ sssctl_prompt(const char *message,
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+ enum sssctl_prompt_result defval);
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+
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+ -errno_t sssctl_run_command(const char *command);
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+ +errno_t sssctl_run_command(const char *const argv[]); /* argv[0] - command */
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+ bool sssctl_start_sssd(bool force);
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+ bool sssctl_stop_sssd(bool force);
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+ bool sssctl_restart_sssd(bool force);
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+ diff --git a/src/tools/sssctl/sssctl_data.c b/src/tools/sssctl/sssctl_data.c
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+ index 8d79b977fdb63fd6c6c925538230bb4ca74a103b..bf2291341668590f4c600237593ea1fd8fe4e4dc 100644
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+ --- a/src/tools/sssctl/sssctl_data.c
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+ +++ b/src/tools/sssctl/sssctl_data.c
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+ @@ -105,15 +105,15 @@ static errno_t sssctl_backup(bool force)
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+ }
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+ }
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+
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+ - ret = sssctl_run_command("sss_override user-export "
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+ - SSS_BACKUP_USER_OVERRIDES);
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+ + ret = sssctl_run_command((const char *[]){"sss_override", "user-export",
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+ + SSS_BACKUP_USER_OVERRIDES, NULL});
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+ if (ret != EOK) {
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+ ERROR("Unable to export user overrides\n");
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+ return ret;
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+ }
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+
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+ - ret = sssctl_run_command("sss_override group-export "
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+ - SSS_BACKUP_GROUP_OVERRIDES);
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+ + ret = sssctl_run_command((const char *[]){"sss_override", "group-export",
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+ + SSS_BACKUP_GROUP_OVERRIDES, NULL});
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+ if (ret != EOK) {
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+ ERROR("Unable to export group overrides\n");
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+ return ret;
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+ @@ -158,8 +158,8 @@ static errno_t sssctl_restore(bool force_start, bool force_restart)
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+ }
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+
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+ if (sssctl_backup_file_exists(SSS_BACKUP_USER_OVERRIDES)) {
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+ - ret = sssctl_run_command("sss_override user-import "
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+ - SSS_BACKUP_USER_OVERRIDES);
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+ + ret = sssctl_run_command((const char *[]){"sss_override", "user-import",
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+ + SSS_BACKUP_USER_OVERRIDES, NULL});
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+ if (ret != EOK) {
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+ ERROR("Unable to import user overrides\n");
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+ return ret;
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+ @@ -167,8 +167,8 @@ static errno_t sssctl_restore(bool force_start, bool force_restart)
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+ }
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+
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+ if (sssctl_backup_file_exists(SSS_BACKUP_USER_OVERRIDES)) {
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+ - ret = sssctl_run_command("sss_override group-import "
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+ - SSS_BACKUP_GROUP_OVERRIDES);
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+ + ret = sssctl_run_command((const char *[]){"sss_override", "group-import",
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+ + SSS_BACKUP_GROUP_OVERRIDES, NULL});
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+ if (ret != EOK) {
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+ ERROR("Unable to import group overrides\n");
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+ return ret;
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+ @@ -296,40 +296,19 @@ errno_t sssctl_cache_expire(struct sss_cmdline *cmdline,
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+ void *pvt)
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+ {
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+ errno_t ret;
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+ - char *cmd_args = NULL;
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+ - const char *cachecmd = SSS_CACHE;
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+ - char *cmd = NULL;
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+ - int i;
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+
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+ - if (cmdline->argc == 0) {
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+ - ret = sssctl_run_command(cachecmd);
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+ - goto done;
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+ + const char **args = talloc_array_size(tool_ctx,
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+ + sizeof(char *),
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+ + cmdline->argc + 2);
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+ + if (!args) {
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+ + return ENOMEM;
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+ }
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+ + memcpy(&args[1], cmdline->argv, sizeof(char *) * cmdline->argc);
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+ + args[0] = SSS_CACHE;
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+ + args[cmdline->argc + 1] = NULL;
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+
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+ - cmd_args = talloc_strdup(tool_ctx, "");
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+ - if (cmd_args == NULL) {
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+ - ret = ENOMEM;
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+ - goto done;
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+ - }
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+ -
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+ - for (i = 0; i < cmdline->argc; i++) {
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+ - cmd_args = talloc_strdup_append(cmd_args, cmdline->argv[i]);
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+ - if (i != cmdline->argc - 1) {
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+ - cmd_args = talloc_strdup_append(cmd_args, " ");
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+ - }
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+ - }
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+ -
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+ - cmd = talloc_asprintf(tool_ctx, "%s %s", cachecmd, cmd_args);
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+ - if (cmd == NULL) {
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+ - ret = ENOMEM;
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+ - goto done;
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+ - }
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+ -
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+ - ret = sssctl_run_command(cmd);
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+ -
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+ -done:
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+ - talloc_free(cmd_args);
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+ - talloc_free(cmd);
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+ + ret = sssctl_run_command(args);
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+
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+ + talloc_free(args);
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+ return ret;
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+ }
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+ diff --git a/src/tools/sssctl/sssctl_logs.c b/src/tools/sssctl/sssctl_logs.c
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+ index 9ff2be05b61108414462d6e17a2c4c4887907a59..ebb2c4571caec487d29ff2d5ceaee1561e845506 100644
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+ --- a/src/tools/sssctl/sssctl_logs.c
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+ +++ b/src/tools/sssctl/sssctl_logs.c
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+ @@ -31,6 +31,7 @@
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+ #include <ldb.h>
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+ #include <popt.h>
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+ #include <stdio.h>
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+ +#include <glob.h>
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+
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+ #include "util/util.h"
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+ #include "tools/common/sss_process.h"
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+ @@ -230,6 +231,7 @@ errno_t sssctl_logs_remove(struct sss_cmdline *cmdline,
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+ {
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+ struct sssctl_logs_opts opts = {0};
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+ errno_t ret;
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+ + glob_t globbuf;
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+
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+ /* Parse command line. */
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+ struct poptOption options[] = {
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+ @@ -253,8 +255,20 @@ errno_t sssctl_logs_remove(struct sss_cmdline *cmdline,
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+
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+ sss_signal(SIGHUP);
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+ } else {
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+ + globbuf.gl_offs = 4;
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+ + ret = glob(LOG_PATH"/*.log", GLOB_ERR|GLOB_DOOFFS, NULL, &globbuf);
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+ + if (ret != 0) {
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+ + DEBUG(SSSDBG_CRIT_FAILURE, "Unable to expand log files list\n");
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+ + return ret;
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+ + }
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+ + globbuf.gl_pathv[0] = discard_const_p(char, "truncate");
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+ + globbuf.gl_pathv[1] = discard_const_p(char, "--no-create");
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+ + globbuf.gl_pathv[2] = discard_const_p(char, "--size");
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+ + globbuf.gl_pathv[3] = discard_const_p(char, "0");
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+ +
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+ PRINT("Truncating log files...\n");
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+ - ret = sssctl_run_command("truncate --no-create --size 0 " LOG_FILES);
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+ + ret = sssctl_run_command((const char * const*)globbuf.gl_pathv);
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+ + globfree(&globbuf);
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+ if (ret != EOK) {
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+ ERROR("Unable to truncate log files\n");
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+ return ret;
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+ @@ -269,8 +283,8 @@ errno_t sssctl_logs_fetch(struct sss_cmdline *cmdline,
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+ void *pvt)
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+ {
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+ const char *file;
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+ - const char *cmd;
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+ errno_t ret;
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+ + glob_t globbuf;
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+
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+ /* Parse command line. */
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+ ret = sss_tool_popt_ex(cmdline, NULL, SSS_TOOL_OPT_OPTIONAL, NULL, NULL,
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+ @@ -280,13 +294,19 @@ errno_t sssctl_logs_fetch(struct sss_cmdline *cmdline,
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+ return ret;
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+ }
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+
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+ - cmd = talloc_asprintf(tool_ctx, "tar -czf %s %s", file, LOG_FILES);
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+ - if (cmd == NULL) {
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+ - ERROR("Out of memory!");
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+ + globbuf.gl_offs = 3;
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+ + ret = glob(LOG_PATH"/*.log", GLOB_ERR|GLOB_DOOFFS, NULL, &globbuf);
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+ + if (ret != 0) {
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+ + DEBUG(SSSDBG_CRIT_FAILURE, "Unable to expand log files list\n");
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+ + return ret;
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+ }
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+ + globbuf.gl_pathv[0] = discard_const_p(char, "tar");
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+ + globbuf.gl_pathv[1] = discard_const_p(char, "-czf");
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+ + globbuf.gl_pathv[2] = discard_const_p(char, file);
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+
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+ PRINT("Archiving log files into %s...\n", file);
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+ - ret = sssctl_run_command(cmd);
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+ + ret = sssctl_run_command((const char * const*)globbuf.gl_pathv);
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+ + globfree(&globbuf);
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+ if (ret != EOK) {
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+ ERROR("Unable to archive log files\n");
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+ return ret;
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+ --
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+ 2.31.1
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+
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