From 61d848b554c8dd1f017b9d187b2a2f6675dbdbe4 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Wed, 22 Nov 2023 17:43:24 -0300 Subject: [PATCH] elf: Ignore LD_BIND_NOW and LD_BIND_NOT for setuid binaries To avoid any environment variable to change setuid binaries semantics. Checked on x86_64-linux-gnu. Reviewed-by: Siddhesh Poyarekar --- elf/rtld.c | 8 ++++++-- elf/tst-env-setuid.c | 4 ++-- sysdeps/generic/unsecvars.h | 2 ++ 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/elf/rtld.c b/elf/rtld.c index 55cdb4836e..d9a6c33b31 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -2604,12 +2604,14 @@ process_envvars (struct dl_main_state *state) case 8: /* Do we bind early? */ - if (memcmp (envline, "BIND_NOW", 8) == 0) + if (!__libc_enable_secure + && memcmp (envline, "BIND_NOW", 8) == 0) { GLRO(dl_lazy) = envline[9] == '\0'; break; } - if (memcmp (envline, "BIND_NOT", 8) == 0) + if (! __libc_enable_secure + && memcmp (envline, "BIND_NOT", 8) == 0) GLRO(dl_bind_not) = envline[9] != '\0'; break; @@ -2686,6 +2688,8 @@ process_envvars (struct dl_main_state *state) if (GLRO(dl_debug_mask) != 0 || GLRO(dl_verbose) != 0 + || GLRO(dl_lazy) != 1 + || GLRO(dl_bind_not) != 0 || state->mode != rtld_mode_normal || state->version_info) _exit (5); diff --git a/elf/tst-env-setuid.c b/elf/tst-env-setuid.c index b1d64ac085..9fa591a136 100644 --- a/elf/tst-env-setuid.c +++ b/elf/tst-env-setuid.c @@ -63,12 +63,12 @@ static const struct envvar_t filtered_envvars[] = { "LD_DEBUG_OUTPUT", "/tmp/some-file" }, { "LD_WARN", FILTERED_VALUE }, { "LD_VERBOSE", FILTERED_VALUE }, + { "LD_BIND_NOW", "0" }, + { "LD_BIND_NOT", "1" }, }; static const struct envvar_t unfiltered_envvars[] = { - { "LD_BIND_NOW", "0" }, - { "LD_BIND_NOT", "1" }, /* Non longer supported option. */ { "LD_ASSUME_KERNEL", UNFILTERED_VALUE }, }; diff --git a/sysdeps/generic/unsecvars.h b/sysdeps/generic/unsecvars.h index 8975df4a14..f1724efe0f 100644 --- a/sysdeps/generic/unsecvars.h +++ b/sysdeps/generic/unsecvars.h @@ -7,6 +7,8 @@ "GLIBC_TUNABLES\0" \ "HOSTALIASES\0" \ "LD_AUDIT\0" \ + "LD_BIND_NOT\0" \ + "LD_BIND_NOW\0" \ "LD_DEBUG\0" \ "LD_DEBUG_OUTPUT\0" \ "LD_DYNAMIC_WEAK\0" \ -- 2.11.4.GIT