Commit a3defbe5 authored Nov 02, 2011 by Jiri Kosina Committed by Linus Torvalds Nov 02, 2011

binfmt_elf: fix PIE execution with randomization disabled



The case of address space randomization being disabled in runtime through
randomize_va_space sysctl is not treated properly in load_elf_binary(),
resulting in SIGKILL coming at exec() time for certain PIE-linked binaries
in case the randomization has been disabled at runtime prior to calling
exec().

Handle the randomize_va_space == 0 case the same way as if we were not
supporting .text randomization at all.

Based on original patch by H.J. Lu and Josh Boyer.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: H.J. Lu <hongjiu.lu@intel.com>
Cc: <stable@kernel.org>
Tested-by: Josh Boyer <jwboyer@redhat.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent b35a35b5

fs/binfmt_elf.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -795,7 +795,16 @@ static int load_elf_binary(struct linux_binprm bprm, struct pt_regs regs)
		* might try to exec. This is because the brk will
		* follow the loader, and is not movable. */
		#if defined(CONFIG_X86) \|\| defined(CONFIG_ARM)
		/* Memory randomization might have been switched off
		* in runtime via sysctl.
		* If that is the case, retain the original non-zero
		* load_bias value in order to establish proper
		* non-randomized mappings.
		*/
		if (current->flags & PF_RANDOMIZE)
		load_bias = 0;
		else
		load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
		#else
		load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
		#endif

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