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([2804:1b3:a7c1:e3c5:c9b5:f382:64ea:c32b]) by smtp.gmail.com with ESMTPSA id gr6-20020a056a004d0600b006ed1ea5219csm21449143pfb.130.2024.04.30.12.32.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Apr 2024 12:32:57 -0700 (PDT) From: Adhemerval Zanella To: libc-alpha@sourceware.org Cc: Joe Simmons-Talbott , Siddhesh Poyarekar Subject: [PATCH 4/4] elf: Make glibc.rtld.enable_secure ignore alias environment variables Date: Tue, 30 Apr 2024 16:25:05 -0300 Message-ID: <20240430192739.1032549-5-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240430192739.1032549-1-adhemerval.zanella@linaro.org> References: <20240430192739.1032549-1-adhemerval.zanella@linaro.org> MIME-Version: 1.0 X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org So tunable with environment variables aliases are also ignored if glibc.rtld.enable_secure is enabled. The tunable parsing is also optimized a bit, where the loop that checks each environment variable only checks for the tunables with aliases instead of all tables. Checked on aarch64-linux-gnu and x86_64-linux-gnu. --- elf/dl-tunables.c | 34 ++++++-- elf/tst-tunables-enable_secure.c | 131 +++++++++++++++++++++++++++---- scripts/gen-tunables.awk | 64 ++++++++++----- 3 files changed, 189 insertions(+), 40 deletions(-) diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c index 63cf8c7ab5..c1a1d1a2e3 100644 --- a/elf/dl-tunables.c +++ b/elf/dl-tunables.c @@ -300,6 +300,10 @@ __tunables_init (char **envp) if (__libc_enable_secure) return; + /* The tunable with environment variable alias are placed at the start of + tunable array. */ + struct tunable_toset_t tunables_env_alias[TUNABLE_NUM_ENV_ALIAS] = { 0 }; + while ((envp = get_next_env (envp, &envname, &envval, &prev_envp)) != NULL) { /* The environment variable is allocated on the stack by the kernel, so @@ -311,29 +315,43 @@ __tunables_init (char **envp) continue; } - for (int i = 0; i < tunables_list_size; i++) + for (int i = 0; i < TUNABLE_NUM_ENV_ALIAS; i++) { tunable_t *cur = &tunable_list[i]; + const char *name = cur->env_alias; - /* Skip over tunables that have either been set already or should be - skipped. */ - if (cur->initialized || cur->env_alias[0] == '\0') + if (name[0] == '\0') continue; - const char *name = cur->env_alias; - - /* We have a match. Initialize and move on to the next line. */ if (tunable_is_name (name, envname)) { size_t envvallen = 0; /* The environment variable is always null-terminated. */ for (const char *p = envval; *p != '\0'; p++, envvallen++); - tunable_initialize (cur, envval, envvallen); + tunables_env_alias[i] = + (struct tunable_toset_t) { cur, envval, envvallen }; break; } } } + + /* Check if glibc.rtld.enable_secure was set and skip over the environment + variables aliases. */ + if (__libc_enable_secure) + return; + + for (int i = 0; i < TUNABLE_NUM_ENV_ALIAS; i++) + { + if (tunables_env_alias[i].t == NULL + || tunables_env_alias[i].t->initialized) + continue; + + if (!tunable_initialize (tunables_env_alias[i].t, + tunables_env_alias[i].value, + tunables_env_alias[i].len)) + parse_tunable_print_error (&tunables_env_alias[i]); + } } void diff --git a/elf/tst-tunables-enable_secure.c b/elf/tst-tunables-enable_secure.c index f5db1c84e9..d4938a2e5c 100644 --- a/elf/tst-tunables-enable_secure.c +++ b/elf/tst-tunables-enable_secure.c @@ -17,6 +17,7 @@ . */ #include +#define TUNABLES_INTERNAL 1 #include #include #include @@ -34,6 +35,8 @@ static int restart; static const struct test_t { const char *env; + const char *extraenv; + bool check_multiple; int32_t expected_malloc_check; int32_t expected_enable_secure; } tests[] = @@ -41,39 +44,124 @@ static const struct test_t /* Expected tunable format. */ /* Tunables should be ignored if enable_secure is set. */ { - "glibc.malloc.check=2:glibc.rtld.enable_secure=1", + "GLIBC_TUNABLES=glibc.malloc.check=2:glibc.rtld.enable_secure=1", + NULL, + false, 0, 1, }, /* Tunables should be ignored if enable_secure is set. */ { - "glibc.rtld.enable_secure=1:glibc.malloc.check=2", + "GLIBC_TUNABLES=glibc.rtld.enable_secure=1:glibc.malloc.check=2", + NULL, + false, 0, 1, }, /* Tunables should be set if enable_secure is unset. */ { - "glibc.rtld.enable_secure=0:glibc.malloc.check=2", + "GLIBC_TUNABLES=glibc.rtld.enable_secure=0:glibc.malloc.check=2", + NULL, + false, 2, 0, }, + /* Tunables should be ignored if enable_secure is set. */ + { + "GLIBC_TUNABLES=glibc.malloc.check=2:glibc.rtld.enable_secure=1", + "MALLOC_CHECK_=2", + false, + 0, + 1, + }, + /* Same as before, but with enviroment alias prior GLIBC_TUNABLES. */ + { + "MALLOC_CHECK_=2", + "GLIBC_TUNABLES=glibc.malloc.check=2:glibc.rtld.enable_secure=1", + false, + 0, + 1, + }, + /* Tunables should be ignored if enable_secure is set. */ + { + "GLIBC_TUNABLES=glibc.rtld.enable_secure=1:glibc.malloc.check=2", + "MALLOC_CHECK_=2", + false, + 0, + 1, + }, + { + "MALLOC_CHECK_=2", + "GLIBC_TUNABLES=glibc.rtld.enable_secure=1:glibc.malloc.check=2", + false, + 0, + 1, + }, + /* Tunables should be set if enable_secure is unset. */ + { + "GLIBC_TUNABLES=glibc.rtld.enable_secure=0:glibc.malloc.check=2", + /* Tunable have precedence over the environment variable. */ + "MALLOC_CHECK_=1", + false, + 2, + 0, + }, + { + "MALLOC_CHECK_=1", + "GLIBC_TUNABLES=glibc.rtld.enable_secure=0:glibc.malloc.check=2", + /* Tunable have precedence over the environment variable. */ + false, + 2, + 0, + }, + /* Tunables should be set if enable_secure is unset. */ + { + "GLIBC_TUNABLES=glibc.rtld.enable_secure=0", + /* Tunable have precedence over the environment variable. */ + "MALLOC_CHECK_=1", + false, + 1, + 0, + }, + /* Tunables should be set if enable_secure is unset. */ + { + "GLIBC_TUNABLES=glibc.rtld.enable_secure=0", + /* Tunable have precedence over the environment variable. */ + "MALLOC_CHECK_=1", + false, + 1, + 0, + }, + /* Check with tunables environment variable alias set multiple times. */ + { + "GLIBC_TUNABLES=glibc.rtld.enable_secure=1:glibc.malloc.check=2", + "MALLOC_CHECK_=2", + true, + 0, + 1, + }, + /* Tunables should be set if enable_secure is unset. */ + { + "GLIBC_TUNABLES=glibc.rtld.enable_secure=0", + /* Tunable have precedence over the environment variable. */ + "MALLOC_CHECK_=1", + true, + 1, + 0, + }, }; static int handle_restart (int i) { if (tests[i].expected_enable_secure == 1) - { - TEST_COMPARE (1, __libc_enable_secure); - } + TEST_COMPARE (1, __libc_enable_secure); else - { - TEST_COMPARE (tests[i].expected_malloc_check, - TUNABLE_GET_FULL (glibc, malloc, check, int32_t, NULL)); - TEST_COMPARE (tests[i].expected_enable_secure, - TUNABLE_GET_FULL (glibc, rtld, enable_secure, int32_t, - NULL)); - } + TEST_COMPARE (tests[i].expected_enable_secure, + TUNABLE_GET_FULL (glibc, rtld, enable_secure, int32_t, + NULL)); + TEST_COMPARE (tests[i].expected_malloc_check, + TUNABLE_GET_FULL (glibc, malloc, check, int32_t, NULL)); return 0; } @@ -112,8 +200,23 @@ do_test (int argc, char *argv[]) printf ("[%d] Spawned test for %s\n", i, tests[i].env); setenv ("GLIBC_TUNABLES", tests[i].env, 1); + + char *envp[2 + TUNABLE_NUM_ENV_ALIAS + 1] = + { + (char *) tests[i].env, + (char *) tests[i].extraenv, + NULL, + }; + if (tests[i].check_multiple) + { + int j; + for (j=0; j < TUNABLE_NUM_ENV_ALIAS; j++) + envp[j + 2] = (char *) tests[i].extraenv; + envp[j + 2] = NULL; + } + struct support_capture_subprocess result - = support_capture_subprogram (spargv[0], spargv, NULL); + = support_capture_subprogram (spargv[0], spargv, envp); support_capture_subprocess_check (&result, "tst-tunables-enable_secure", 0, sc_allow_stderr); support_capture_subprocess_free (&result); diff --git a/scripts/gen-tunables.awk b/scripts/gen-tunables.awk index 9f5336381e..9a18aa6861 100644 --- a/scripts/gen-tunables.awk +++ b/scripts/gen-tunables.awk @@ -14,6 +14,7 @@ BEGIN { top_ns="" max_name_len=0 max_alias_len=0 + num_env_alias=0 } # Skip over blank lines and comments. @@ -60,6 +61,8 @@ $1 == "}" { } if (!env_alias[top_ns,ns,tunable]) { env_alias[top_ns,ns,tunable] = "{0}" + } else { + num_env_alias = num_env_alias + 1 } len = length(top_ns"."ns"."tunable) if (len > max_name_len) @@ -125,6 +128,39 @@ $1 == "}" { } } +function print_tunable_id_t (envfirst) +{ + for (tnm in types) { + split (tnm, indices, SUBSEP); + t = indices[1]; + n = indices[2]; + m = indices[3]; + if ((envfirst && env_alias[t,n,m] == "{0}") \ + || (!envfirst && env_alias[t,n,m] != "{0}")) { + continue; + } + printf (" TUNABLE_ENUM_NAME(%s, %s, %s),\n", t, n, m); + } +} + +function print_tunable_entry (envfirst) +{ + for (tnm in types) { + split (tnm, indices, SUBSEP); + t = indices[1]; + n = indices[2]; + m = indices[3]; + if ((envfirst && env_alias[t,n,m] == "{0}") \ + || (!envfirst && env_alias[t,n,m] != "{0}")) { + continue; + } + printf (" {TUNABLE_NAME_S(%s, %s, %s)", t, n, m) + printf (", {TUNABLE_TYPE_%s, %s, %s}, {%s}, {%s}, false, %s},\n", + types[t,n,m], minvals[t,n,m], maxvals[t,n,m], default_val[t,n,m], + default_val[t,n,m], env_alias[t,n,m]); + } +} + END { if (ns != "") { print "Unterminated namespace. Is a closing brace missing?" @@ -138,35 +174,27 @@ END { print "#endif" print "#include \n" + # asort (types) + # Now, the enum names print "\ntypedef enum" print "{" - for (tnm in types) { - split (tnm, indices, SUBSEP); - t = indices[1]; - n = indices[2]; - m = indices[3]; - printf (" TUNABLE_ENUM_NAME(%s, %s, %s),\n", t, n, m); - } + # Make the tunable with environment variables aliases first, their index + # will be used in the tunable parsing. + print_tunable_id_t(1) + print_tunable_id_t(0) print "} tunable_id_t;\n" print "\n#ifdef TUNABLES_INTERNAL" # Internal definitions. print "# define TUNABLE_NAME_MAX " (max_name_len + 1) print "# define TUNABLE_ALIAS_MAX " (max_alias_len + 1) + print "# define TUNABLE_NUM_ENV_ALIAS " (num_env_alias) print "# include \"dl-tunable-types.h\"" # Finally, the tunable list. - print "static tunable_t tunable_list[] attribute_relro = {" - for (tnm in types) { - split (tnm, indices, SUBSEP); - t = indices[1]; - n = indices[2]; - m = indices[3]; - printf (" {TUNABLE_NAME_S(%s, %s, %s)", t, n, m) - printf (", {TUNABLE_TYPE_%s, %s, %s}, {%s}, {%s}, false, %s},\n", - types[t,n,m], minvals[t,n,m], maxvals[t,n,m], default_val[t,n,m], - default_val[t,n,m], env_alias[t,n,m]); - } + print "static tunable_t tunable_list[] attribute_relro __attribute_used__ = {" + print_tunable_entry(1) + print_tunable_entry(0) print "};" print "#endif" }