From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org, Siddhesh Poyarekar <siddhesh@sourceware.org>
Subject: [PATCH v3 12/19] elf: Ignore LD_PROFILE for setuid binaries
Date: Mon, 6 Nov 2023 17:25:45 -0300 [thread overview]
Message-ID: <20231106202552.3404059-13-adhemerval.zanella@linaro.org> (raw)
In-Reply-To: <20231106202552.3404059-1-adhemerval.zanella@linaro.org>
Loader does not ignore LD_PROFILE in secure-execution mode (different
than man-page states [1]), rather it uses a different path
(/var/profile) and ignore LD_PROFILE_OUTPUT.
Allowing secure-execution profiling is already a non good security
boundary, since it enables different code paths and extra OS access by
the process. But by ignoring LD_PROFILE_OUTPUT, the resulting profile
file might also be acceded in a racy manner since the file name does not
use any process-specific information (such as pid, timing, etc.).
Another side-effect is it forces lazy binding even on libraries that
might be with DF_BIND_NOW.
[1] https://man7.org/linux/man-pages/man8/ld.so.8.html
---
elf/Makefile | 3 +++
elf/rtld.c | 8 +++-----
elf/tst-env-setuid.c | 12 +++++++++++-
3 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/elf/Makefile b/elf/Makefile
index 52981c19d0..08896bb895 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -2983,3 +2983,6 @@ $(objpfx)tst-dlclose-lazy.out: \
$(objpfx)tst-dlclose-lazy-mod1.so $(objpfx)tst-dlclose-lazy-mod2.so
tst-env-setuid-ARGS = -- $(host-test-program-cmd)
+
+# Reuse a module with a SONAME, to specific as the LD_PROFILE.
+$(objpfx)tst-env-setuid: $(objpfx)tst-sonamemove-runmod2.so
diff --git a/elf/rtld.c b/elf/rtld.c
index 51b6d9f326..a09cf2a9df 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -361,6 +361,7 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
._dl_fpu_control = _FPU_DEFAULT,
._dl_pagesize = EXEC_PAGESIZE,
._dl_inhibit_cache = 0,
+ ._dl_profile_output = "/var/tmp",
/* Function pointers. */
._dl_debug_printf = _dl_debug_printf,
@@ -2534,10 +2535,6 @@ process_envvars (struct dl_main_state *state)
char *envline;
char *debug_output = NULL;
- /* This is the default place for profiling data file. */
- GLRO(dl_profile_output)
- = &"/var/tmp\0/var/profile"[__libc_enable_secure ? 9 : 0];
-
while ((envline = _dl_next_ld_env_entry (&runp)) != NULL)
{
size_t len = 0;
@@ -2586,7 +2583,8 @@ process_envvars (struct dl_main_state *state)
}
/* Which shared object shall be profiled. */
- if (memcmp (envline, "PROFILE", 7) == 0 && envline[8] != '\0')
+ if (!__libc_enable_secure
+ && memcmp (envline, "PROFILE", 7) == 0 && envline[8] != '\0')
GLRO(dl_profile) = &envline[8];
break;
diff --git a/elf/tst-env-setuid.c b/elf/tst-env-setuid.c
index ba295a6a14..76b8e1fb45 100644
--- a/elf/tst-env-setuid.c
+++ b/elf/tst-env-setuid.c
@@ -34,6 +34,9 @@ static char SETGID_CHILD[] = "setgid-child";
#define FILTERED_VALUE "some-filtered-value"
#define UNFILTERED_VALUE "some-unfiltered-value"
+/* It assumes no other programs is being profile with a library with same
+ SONAME using the default folder. */
+#define PROFILE_LIB "tst-sonamemove-runmod2.so"
struct envvar_t
{
@@ -50,7 +53,7 @@ static const struct envvar_t filtered_envvars[] =
{ "LD_HWCAP_MASK", FILTERED_VALUE },
{ "LD_LIBRARY_PATH", FILTERED_VALUE },
{ "LD_PRELOAD", FILTERED_VALUE },
- { "LD_PROFILE", FILTERED_VALUE },
+ { "LD_PROFILE", "tst-sonamemove-runmod2.so" },
{ "MALLOC_ARENA_MAX", FILTERED_VALUE },
{ "MALLOC_PERTURB_", FILTERED_VALUE },
{ "MALLOC_TRACE", FILTERED_VALUE },
@@ -87,6 +90,13 @@ test_child (void)
ret |= !(env != NULL && strcmp (env, e->value) == 0);
}
+ /* Also check if no profile file was created. */
+ {
+ char *profilepath = xasprintf ("/var/tmp/%s.profile", PROFILE_LIB);
+ ret |= !access (profilepath, R_OK);
+ free (profilepath);
+ }
+
return ret;
}
--
2.34.1
next prev parent reply other threads:[~2023-11-06 20:26 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-06 20:25 [PATCH v3 00/19] Improve loader environment variable handling Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 01/19] elf: Remove /etc/suid-debug support Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 02/19] elf: Add GLIBC_TUNABLES to unsecvars Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 03/19] elf: Ignore GLIBC_TUNABLES for setuid/setgid binaries Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 04/19] elf: Add all malloc tunable to unsecvars Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 05/19] elf: Do not process invalid tunable format Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 06/19] elf: Do not parse ill-formatted strings Adhemerval Zanella
2023-11-20 21:48 ` Siddhesh Poyarekar
2023-11-06 20:25 ` [PATCH v3 07/19] elf: Fix _dl_debug_vdprintf to work before self-relocation Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 08/19] elf: Emit warning if tunable is ill-formatted Adhemerval Zanella
2023-11-20 21:50 ` Siddhesh Poyarekar
2023-11-06 20:25 ` [PATCH v3 09/19] x86: Use dl-symbol-redir-ifunc.h on cpu-tunables Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 10/19] s390: " Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 11/19] elf: Do not duplicate the GLIBC_TUNABLES string Adhemerval Zanella
2023-11-20 22:44 ` Siddhesh Poyarekar
2023-11-21 18:12 ` Adhemerval Zanella Netto
2023-11-22 11:39 ` Adhemerval Zanella Netto
2023-11-22 12:23 ` Siddhesh Poyarekar
2023-11-22 13:03 ` Adhemerval Zanella Netto
2023-11-22 13:24 ` Siddhesh Poyarekar
2023-11-22 14:13 ` Adhemerval Zanella Netto
2023-11-06 20:25 ` Adhemerval Zanella [this message]
2023-11-20 22:47 ` [PATCH v3 12/19] elf: Ignore LD_PROFILE for setuid binaries Siddhesh Poyarekar
2023-11-06 20:25 ` [PATCH v3 13/19] elf: Remove LD_PROFILE for static binaries Adhemerval Zanella
2023-11-20 22:55 ` Siddhesh Poyarekar
2023-11-06 20:25 ` [PATCH v3 14/19] elf: Ignore loader debug env vars for setuid Adhemerval Zanella
2023-11-20 22:57 ` Siddhesh Poyarekar
2023-11-21 18:24 ` Adhemerval Zanella Netto
2023-11-06 20:25 ` [PATCH v3 15/19] elf: Remove any_debug from dl_main_state Adhemerval Zanella
2023-11-20 22:58 ` Siddhesh Poyarekar
2023-11-06 20:25 ` [PATCH v3 16/19] elf: Ignore LD_LIBRARY_PATH and debug env var for setuid for static Adhemerval Zanella
2023-11-20 22:59 ` Siddhesh Poyarekar
2023-11-06 20:25 ` [PATCH v3 17/19] elf: Add comments on how LD_AUDIT and LD_PRELOAD handle __libc_enable_secure Adhemerval Zanella
2023-11-06 20:25 ` [PATCH v3 18/19] elf: Ignore LD_BIND_NOW and LD_BIND_NOT for setuid binaries Adhemerval Zanella
2023-11-20 23:02 ` Siddhesh Poyarekar
2023-11-06 20:25 ` [PATCH v3 19/19] elf: Refactor process_envvars Adhemerval Zanella
2023-11-20 23:09 ` Siddhesh Poyarekar
2023-11-21 19:00 ` Adhemerval Zanella Netto
2023-11-20 23:12 ` [PATCH v3 00/19] Improve loader environment variable handling Siddhesh Poyarekar
2023-11-21 19:37 ` Adhemerval Zanella Netto
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