From 866067e6282f07b7a40efb19bb921628dd71cadc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pavel=20B=C5=99ezina?= Date: Mon, 16 Aug 2021 15:04:28 +0200 Subject: [PATCH] sssd-2.5.2-5: Fix CVE-2021-3621 --- 0002-TOOLS-replace-system-with-execvp.patch | 277 ++++++++++++++++++++ sssd.spec | 6 +- 2 files changed, 282 insertions(+), 1 deletion(-) create mode 100644 0002-TOOLS-replace-system-with-execvp.patch diff --git a/0002-TOOLS-replace-system-with-execvp.patch b/0002-TOOLS-replace-system-with-execvp.patch new file mode 100644 index 0000000..081bf29 --- /dev/null +++ b/0002-TOOLS-replace-system-with-execvp.patch @@ -0,0 +1,277 @@ +From 5a9a2f53ff44b1bd25a6de7c4ba91c709b63b0ba Mon Sep 17 00:00:00 2001 +From: Alexey Tikhonov +Date: Fri, 18 Jun 2021 13:17:19 +0200 +Subject: [PATCH] TOOLS: replace system() with execvp() to avoid execution of + user supplied command + +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. + +:fixes: CVE-2021-3621 +--- + 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 2997dbf968acdd0b9821f726414f8ae1cf34b5d8..8adaf30910e13ea9e7c8ab8b151920c4f307427b 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 0115b2457c48bb0b8ad8ef8fd20d6fc81bdb58b4..599ef65196fcae6454cd5b46aa7a2cf6e7cbba73 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 8d79b977fdb63fd6c6c925538230bb4ca74a103b..bf2291341668590f4c600237593ea1fd8fe4e4dc 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; ++ 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; + +- cmd_args = talloc_strdup(tool_ctx, ""); +- if (cmd_args == NULL) { +- ret = ENOMEM; +- goto done; +- } +- +- 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 9ff2be05b61108414462d6e17a2c4c4887907a59..ebb2c4571caec487d29ff2d5ceaee1561e845506 100644 +--- a/src/tools/sssctl/sssctl_logs.c ++++ b/src/tools/sssctl/sssctl_logs.c +@@ -31,6 +31,7 @@ + #include + #include + #include ++#include + + #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; +-- +2.31.1 + diff --git a/sssd.spec b/sssd.spec index 15a81c5..534a70a 100644 --- a/sssd.spec +++ b/sssd.spec @@ -27,7 +27,7 @@ Name: sssd Version: 2.5.2 -Release: 4%{?dist} +Release: 5%{?dist} Summary: System Security Services Daemon License: GPLv3+ URL: https://github.com/SSSD/sssd/ @@ -35,6 +35,7 @@ Source0: https://github.com/SSSD/sssd/releases/download/2.5.2/sssd-2.5.2.tar.gz ### Patches ### Patch0001: 0001-Basics-of-subid-ranges-support-for-IPA-provider.patch +Patch0002: 0002-TOOLS-replace-system-with-execvp.patch ### Dependencies ### @@ -1000,6 +1001,9 @@ fi %systemd_postun_with_restart sssd.service %changelog +* Mon Aug 16 2021 Pavel Březina - 2.5.2-5 +- Fix CVE-2021-3621 + * Mon Aug 09 2021 Pavel Březina - 2.5.2-4 - Disable running files provider by default - Support subid ranges managed by FreeIPA