diff options
| author |   Siddhesh Poyarekar <siddhesh@sourceware.org> | 2017-03-07 20:52:04 +0530 |
|---|---|---|
| committer |   Andreas K. Hüttel <dilfridge@gentoo.org> | 2017-08-18 23:46:33 +0200 |
| commit | c0f9de764c3252431e29646d4ccb6da430c34469 (patch) | |
| tree | 78b463fe29ef935b1a2849f0bdeb93b90c5c1c46 | |
| parent | Add IS_IN guard to multiarch/IFUNC implementations (diff) | |
| download | glibc-c0f9de764c3252431e29646d4ccb6da430c34469.tar.gz glibc-c0f9de764c3252431e29646d4ccb6da430c34469.tar.bz2 glibc-c0f9de764c3252431e29646d4ccb6da430c34469.zip | |
Ignore and remove LD_HWCAP_MASK for AT_SECURE programs (bug #21209)
The LD_HWCAP_MASK environment variable may alter the selection of
function variants for some architectures. For AT_SECURE process it
means that if an outdated routine has a bug that would otherwise not
affect newer platforms by default, LD_HWCAP_MASK will allow that bug
to be exploited.
To be on the safe side, ignore and disable LD_HWCAP_MASK for setuid
binaries.
[BZ #21209]
* elf/rtld.c (process_envvars): Ignore LD_HWCAP_MASK for
AT_SECURE processes.
* sysdeps/generic/unsecvars.h: Add LD_HWCAP_MASK.
* elf/tst-env-setuid.c (test_parent): Test LD_HWCAP_MASK.
(test_child): Likewise.
* elf/Makefile (tst-env-setuid-ENV): Add LD_HWCAP_MASK.
| -rw-r--r-- | elf/Makefile | 3 | ||||
| -rw-r--r-- | elf/rtld.c | 3 | ||||
| -rw-r--r-- | elf/tst-env-setuid.c | 12 | ||||
| -rw-r--r-- | sysdeps/generic/unsecvars.h | 1 |
4 files changed, 17 insertions, 2 deletions
diff --git a/elf/Makefile b/elf/Makefile index 1d27a88f02..883dd8f013 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -1398,6 +1398,7 @@ $(objpfx)tst-nodelete-dlclose: $(objpfx)tst-nodelete-dlclose-dso.so $(objpfx)tst-nodelete-dlclose.out: $(objpfx)tst-nodelete-dlclose-dso.so \ $(objpfx)tst-nodelete-dlclose-plugin.so -tst-env-setuid-ENV = MALLOC_CHECK_=2 MALLOC_MMAP_THRESHOLD_=4096 +tst-env-setuid-ENV = MALLOC_CHECK_=2 MALLOC_MMAP_THRESHOLD_=4096 \ + LD_HWCAP_MASK=0xffffffff tst-env-setuid-tunables-ENV = \ GLIBC_TUNABLES=glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096 diff --git a/elf/rtld.c b/elf/rtld.c index c76cbfca33..7c049dfbe8 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -2521,7 +2521,8 @@ process_envvars (enum mode *modep) case 10: /* Mask for the important hardware capabilities. */ - if (memcmp (envline, "HWCAP_MASK", 10) == 0) + if (!__libc_enable_secure + && memcmp (envline, "HWCAP_MASK", 10) == 0) GLRO(dl_hwcap_mask) = __strtoul_internal (&envline[11], NULL, 0, 0); break; diff --git a/elf/tst-env-setuid.c b/elf/tst-env-setuid.c index 6ec3fa5874..eec408eb5d 100644 --- a/elf/tst-env-setuid.c +++ b/elf/tst-env-setuid.c @@ -213,6 +213,12 @@ test_child (void) return 1; } + if (getenv ("LD_HWCAP_MASK") != NULL) + { + printf ("LD_HWCAP_MASK still set\n"); + return 1; + } + return 0; } #endif @@ -233,6 +239,12 @@ test_parent (void) return 1; } + if (getenv ("LD_HWCAP_MASK") == NULL) + { + printf ("LD_HWCAP_MASK lost\n"); + return 1; + } + return 0; } #endif diff --git a/sysdeps/generic/unsecvars.h b/sysdeps/generic/unsecvars.h index a74083786e..5ea8a4a259 100644 --- a/sysdeps/generic/unsecvars.h +++ b/sysdeps/generic/unsecvars.h @@ -16,6 +16,7 @@ "LD_DEBUG\0" \ "LD_DEBUG_OUTPUT\0" \ "LD_DYNAMIC_WEAK\0" \ + "LD_HWCAP_MASK\0" \ "LD_LIBRARY_PATH\0" \ "LD_ORIGIN_PATH\0" \ "LD_PRELOAD\0" \ |