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Commit a3defbe5 authored by Jiri Kosina's avatar Jiri Kosina Committed by Linus Torvalds
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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: default avatarJiri 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: default avatarJosh Boyer <jwboyer@redhat.com>
Acked-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus 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