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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-11-06 17:25:45 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-11-21 16:15:42 -0300 |
| commit | 4a133885a7c8ae7ebe34e36fcdb353f8e94c810f (patch) | |
| tree | 3e7b0282fa619485f4a6f3873457e112b735962b | |
| parent | 1c87f71a36e21fa851117c151b3c492fa3eede5b (diff) | |
| download | glibc-4a133885a7c8ae7ebe34e36fcdb353f8e94c810f.zip glibc-4a133885a7c8ae7ebe34e36fcdb353f8e94c810f.tar.gz glibc-4a133885a7c8ae7ebe34e36fcdb353f8e94c810f.tar.bz2 | |
elf: Ignore LD_PROFILE for setuid binaries
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
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
| -rw-r--r-- | elf/Makefile | 3 | ||||
| -rw-r--r-- | elf/rtld.c | 8 | ||||
| -rw-r--r-- | elf/tst-env-setuid.c | 12 |
3 files changed, 17 insertions, 6 deletions
diff --git a/elf/Makefile b/elf/Makefile index 1af8ca4..414fdbd 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -3002,3 +3002,6 @@ $(objpfx)tst-non-directory-path.out: tst-non-directory-path.sh \ $(evaluate-test) 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 @@ -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 ba295a6..76b8e1f 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; } |