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| author | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2017-06-20 05:59:17 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2017-06-20 05:59:17 +0200 |
| commit | 3776f38fcd267c127ba5eb222e2c614c191744aa (patch) | |
| tree | 7d196b5415bd1cb87860ce5defd3bffa36b2573d | |
| parent | c69d4a0f680a24fdbe323764a50382ad324041e9 (diff) | |
| download | glibc-3776f38fcd267c127ba5eb222e2c614c191744aa.tar.gz | |
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means that if an outdated routine has a bug that would otherwise not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.
(cherry picked from commit 1c1243b6fc33c029488add276e56570a07803bfd)
| -rw-r--r-- | ChangeLog | 10 | ||||
| -rw-r--r-- | NEWS | 1 | ||||
| -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 |
6 files changed, 28 insertions, 2 deletions
@@ -1,3 +1,13 @@ +2017-03-07 Siddhesh Poyarekar <siddhesh@sourceware.org> + + [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. + 2017-06-19 Florian Weimer <fweimer@redhat.com> * elf/rtld.c (audit_list_string): New variable. @@ -13,6 +13,7 @@ The following bugs are resolved with this release: [21015] Document and fix --enable-bind-now [21109] Tunables broken on big-endian [21115] sunrpc: Use-after-free in error path in clntudp_call + [21209] Ignore and remove LD_HWCAP_MASK for AT_SECURE programs [21289] Fix symbol redirect for fts_set [21386] Assertion in fork for distinct parent PID is incorrect [21624] Unsafe alloca allows local attackers to alias stack and heap (CVE-2017-1000366) diff --git a/elf/Makefile b/elf/Makefile index 61abeb59ee..cc4aeb25b6 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 369724babe..9362a21e73 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -2534,7 +2534,8 @@ 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" \ |