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| author | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2017-03-07 20:52:04 +0530 |
|---|---|---|
| committer | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2017-03-07 20:52:04 +0530 |
| commit | 1c1243b6fc33c029488add276e56570a07803bfd (patch) | |
| tree | dc024978a5a16a4bd027a4f28508ab503983fa6c /elf | |
| parent | a7055e5935f7ee63d622c66a7dde16ba0de674e0 (diff) | |
| download | glibc-1c1243b6fc33c029488add276e56570a07803bfd.tar.gz glibc-1c1243b6fc33c029488add276e56570a07803bfd.tar.xz glibc-1c1243b6fc33c029488add276e56570a07803bfd.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 For AT_SECURE process it means that if an outdated routine has a bug that would otherwise not affect newer platforms by default, LD_HWCAP_MASK will allow that bug to be exploited.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.
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/Makefile | 3 | ||||
| -rw-r--r-- | elf/rtld.c | 3 | ||||
| -rw-r--r-- | elf/tst-env-setuid.c | 12 |
3 files changed, 16 insertions, 2 deletions
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 a036ece956..5986eaf4a1 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -2404,7 +2404,8 @@ 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 |