From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Cc: Joe Simmons-Talbott <josimmon@redhat.com>,
Siddhesh Poyarekar <siddhesh@sourceware.org>
Subject: [PATCH v3 4/4] elf: Make glibc.rtld.enable_secure ignore alias environment variables
Date: Mon, 6 May 2024 13:18:48 -0300 [thread overview]
Message-ID: <20240506161955.1570278-5-adhemerval.zanella@linaro.org> (raw)
In-Reply-To: <20240506161955.1570278-1-adhemerval.zanella@linaro.org>
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 | 36 ++++++--
elf/tst-tunables-enable_secure.c | 136 +++++++++++++++++++++++++++----
scripts/gen-tunables.awk | 16 +++-
3 files changed, 164 insertions(+), 24 deletions(-)
diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
index 63cf8c7ab5..147cc4cf23 100644
--- a/elf/dl-tunables.c
+++ b/elf/dl-tunables.c
@@ -300,6 +300,9 @@ __tunables_init (char **envp)
if (__libc_enable_secure)
return;
+ enum { tunable_num_env_alias = array_length (tunable_env_alias_list) };
+ 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 +314,44 @@ __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];
+ tunable_t *cur = &tunable_list[tunable_env_alias_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++)
+ {
+ /* Skip over tunables that have either been set or already initialized. */
+ 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..99a065e8db 100644
--- a/elf/tst-tunables-enable_secure.c
+++ b/elf/tst-tunables-enable_secure.c
@@ -17,6 +17,10 @@
<https://www.gnu.org/licenses/>. */
#include <array_length.h>
+/* The test uses the tunable_env_alias_list size, which is only exported for
+ ld.so. This will result in a copy of tunable_list and
+ tunable_env_alias_list, which is ununsed by the test itself. */
+#define TUNABLES_INTERNAL 1
#include <dl-tunables.h>
#include <getopt.h>
#include <intprops.h>
@@ -34,6 +38,8 @@ 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 +47,124 @@ 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;
}
@@ -106,14 +197,31 @@ do_test (int argc, char *argv[])
spargv[i] = NULL;
}
+ enum { tunable_num_env_alias = array_length (tunable_env_alias_list) };
+
for (int i = 0; i < array_length (tests); i++)
{
snprintf (nteststr, sizeof nteststr, "%d", i);
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..fc3b41376f 100644
--- a/scripts/gen-tunables.awk
+++ b/scripts/gen-tunables.awk
@@ -156,7 +156,7 @@ END {
print "# define TUNABLE_ALIAS_MAX " (max_alias_len + 1)
print "# include \"dl-tunable-types.h\""
# Finally, the tunable list.
- print "static tunable_t tunable_list[] attribute_relro = {"
+ print "static tunable_t tunable_list[] attribute_relro __attribute_used__ = {"
for (tnm in types) {
split (tnm, indices, SUBSEP);
t = indices[1];
@@ -168,5 +168,19 @@ END {
default_val[t,n,m], env_alias[t,n,m]);
}
print "};"
+
+ # Map of tunable with environment variables aliases used during parsing. */
+ print "\nstatic const tunable_id_t tunable_env_alias_list[] ="
+ printf "{\n"
+ for (tnm in types) {
+ split (tnm, indices, SUBSEP);
+ t = indices[1];
+ n = indices[2];
+ m = indices[3];
+ if (env_alias[t,n,m] != "{0}") {
+ printf (" TUNABLE_ENUM_NAME(%s, %s, %s),\n", t, n, m);
+ }
+ }
+ printf "};\n"
print "#endif"
}
--
2.43.0
next prev parent reply other threads:[~2024-05-06 16:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-06 16:18 [PATCH v3 0/4] More tunable fixes Adhemerval Zanella
2024-05-06 16:18 ` [PATCH v3 1/4] elf: Only process multiple tunable once (BZ 31686) Adhemerval Zanella
2024-05-06 16:18 ` [PATCH v3 2/4] elf: Remove glibc.rtld.enable_secure check from parse_tunables_string Adhemerval Zanella
2024-05-06 16:18 ` [PATCH v3 3/4] support: Add envp argument to support_capture_subprogram Adhemerval Zanella
2024-05-06 16:18 ` Adhemerval Zanella [this message]
2024-05-07 14:33 ` [PATCH v3 4/4] elf: Make glibc.rtld.enable_secure ignore alias environment variables Siddhesh Poyarekar
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