patches/glibc/ports-2.12.1/340-dl_execstack-PaX-support.patch
author "Benoît THÉBAUDEAU" <benoit.thebaudeau@advansee.com>
Thu Jul 28 22:09:31 2011 +0200 (2011-07-28)
changeset 2573 424fa2092ace
permissions -rw-r--r--
scripts/libc: do not build add-ons by default

Currently, no --enable-add-ons option is passed to libc configure when
"$(do_libc_add_ons_list ,)" is empty, which makes configure automatically search
for present add-ons. In that case, all present add-ons are built, although
no add-on was selected by the user in the config. Moreover, this can make the
configure fail if some non-standard add-ons like eglibc-localedef are present.

This behavior also leads to an inconsistency from a user point of view between
the following cases:
- LIBC_ADDONS_LIST="", LIBC_GLIBC_USE_PORTS=n and THREADS="none" in the config,
which makes "$(do_libc_add_ons_list ,)" return "", so all present add-ons
are built.
- LIBC_ADDONS_LIST="", LIBC_GLIBC_USE_PORTS=n and THREADS!="none" in the
config, which makes "$(do_libc_add_ons_list ,)" return the add-on supporting
the chosen threading implementation, e.g. "nptl", so only this add-on is
built.

This patch disables the building of all add-ons in that case.

It is still possible to build all present add-ons by adding --enable-add-ons to
LIBC_GLIBC_EXTRA_CONFIG_ARRAY.

Signed-off-by: "Benoît THÉBAUDEAU" <benoit.thebaudeau@advansee.com>
yann@2437
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	With latest versions of glibc, a lot of apps failed on a PaX enabled
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	system with:
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		 cannot enable executable stack as shared object requires: Permission denied
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	This is due to PaX 'exec-protecting' the stack, and ld.so then trying
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	to make the stack executable due to some libraries not containing the
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	PT_GNU_STACK section.  Bug #32960.  <azarah@gentoo.org> (12 Nov 2003).
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	Patch also NPTL. Bug #116086. <kevquinn@gentoo.org> (20 Dec 2005).
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diff -durN glibc-2.12.1.orig/nptl/allocatestack.c glibc-2.12.1/nptl/allocatestack.c
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--- glibc-2.12.1.orig/nptl/allocatestack.c	2009-01-29 21:34:16.000000000 +0100
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+++ glibc-2.12.1/nptl/allocatestack.c	2009-11-13 00:50:33.000000000 +0100
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@@ -329,7 +329,8 @@
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 # error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
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 #endif
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   if (mprotect (stack, len, PROT_READ | PROT_WRITE | PROT_EXEC) != 0)
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-    return errno;
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+    if (errno != EACCES) /* PAX is enabled */
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+    	return errno;
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   return 0;
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 }
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diff -durN glibc-2.12.1.orig/sysdeps/unix/sysv/linux/dl-execstack.c glibc-2.12.1/sysdeps/unix/sysv/linux/dl-execstack.c
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--- glibc-2.12.1.orig/sysdeps/unix/sysv/linux/dl-execstack.c	2006-01-08 09:21:15.000000000 +0100
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+++ glibc-2.12.1/sysdeps/unix/sysv/linux/dl-execstack.c	2009-11-13 00:50:33.000000000 +0100
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@@ -63,7 +63,10 @@
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       else
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 # endif
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 	{
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-	  result = errno;
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+	  if (errno == EACCES)  /* PAX is enabled */
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+	    result = 0;
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+	  else
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+	    result = errno;
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 	  goto out;
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 	}
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     }
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@@ -89,7 +92,12 @@
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 	page -= size;
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       else
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 	{
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-	  if (errno != ENOMEM)	/* Unexpected failure mode.  */
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+	  if (errno == EACCES)		/* PAX is enabled */
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+	    {
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+	      result = 0;
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+	      goto out;
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+	    }
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+	  else if (errno != ENOMEM)	/* Unexpected failure mode.  */
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 	    {
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 	      result = errno;
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 	      goto out;
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@@ -115,7 +123,12 @@
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 	page += size;
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       else
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 	{
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-	  if (errno != ENOMEM)	/* Unexpected failure mode.  */
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+	  if (errno == EACCES)		/* PAX is enabled */
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+	    {
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+	      result = 0;
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+	      goto out;
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+	    }
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+	  else if (errno != ENOMEM)	/* Unexpected failure mode.  */
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 	    {
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 	      result = errno;
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 	      goto out;