patches/glibc/ports-2.12.1/340-dl_execstack-PaX-support.patch
author "Benoît Thébaudeau" <benoit.thebaudeau@advansee.com>
Fri Jan 27 13:31:16 2012 +0100 (2012-01-27)
changeset 2854 a70abdbfa342
permissions -rw-r--r--
complibs/cloog: fix linking with libm

In Ubuntu 11.04 and 11.10, the default options for ld have changed.
--no-copy-dt-needed-entries and --as-needed are now enabled by default, which
causes errors like:

[EXTRA] Checking CLooG/ppl
[DEBUG] ==> Executing: 'make' '-j3' '-s' 'check'
[ALL ] Making check in .
[ALL ] config.status: creating include/cloog/cloog-config.h
[ALL ] config.status: include/cloog/cloog-config.h is unchanged
[ALL ] libtool: link: i686-build_pc-linux-gnu-gcc -Wall -fomit-frame-pointer
-pipe -o cloog cloog.o -L/<snip>/build/static/lib ./.libs/libcloog.a -lm
/<snip>/build/static/lib/libppl_c.a /<snip>/build/static/lib/libpwl.a
/<snip>/build/static/lib/libppl.a /<snip>/build/static/lib/libgmpxx.a
/<snip>/build/static/lib/libgmp.a -lstdc++
[ALL ] /usr/bin/ld: /<snip>/build/static/lib/libppl.a(MIP_Problem.o):
undefined reference to symbol 'sqrt@@GLIBC_2.0'
[ALL ] /usr/bin/ld: note: 'sqrt@@GLIBC_2.0' is defined in DSO
/usr/lib/gcc/i686-linux-gnu/4.6.1/../../../i386-linux-gnu/libm.so so try adding
it to the linker command line
[ALL ] /usr/lib/gcc/i686-linux-gnu/4.6.1/../../../i386-linux-gnu/libm.so:
could not read symbols: Invalid operation
[ALL ] collect2: ld returned 1 exit status
[ERROR] make[2]: *** [cloog] Error 1
[ERROR] make[1]: *** [check-recursive] Error 1

See:
https://wiki.ubuntu.com/NattyNarwhal/ToolchainTransition

This patch fixes these errors by placing '-lm' at the right place on the command
line as libppl requires libm when linking cloog.

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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yann@2437
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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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yann@2437
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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;