GNU C Library master sources branch release/2.25/master updated. glibc-2.25-22-g3776f38

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- Log -----------------------------------------------------------------
http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=3776f38fcd267c127ba5eb222e2c614c191744aa

commit 3776f38fcd267c127ba5eb222e2c614c191744aa
Author: Siddhesh Poyarekar <siddhesh@sourceware.org>
Date:   Tue Jun 20 05:59:17 2017 +0200

    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    means that if an outdated routine has a bug that would otherwise not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)

diff --git a/ChangeLog b/ChangeLog
index 67ce0aa..85f1e0a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -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.
diff --git a/NEWS b/NEWS
index 29079e8..7be238c 100644
--- a/NEWS
+++ b/NEWS
@@ -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 61abeb5..cc4aeb2 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 369724b..9362a21 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 6ec3fa5..eec408e 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 a740837..5ea8a4a 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"							      \

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                   |   10 ++++++++++
 NEWS                        |    1 +
 elf/Makefile                |    3 ++-
 elf/rtld.c                  |    3 ++-
 elf/tst-env-setuid.c        |   12 ++++++++++++
 sysdeps/generic/unsecvars.h |    1 +
 6 files changed, 28 insertions(+), 2 deletions(-)


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