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authorJiri Kosina <jkosina@suse.cz>2011-11-02 13:37:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-11-02 16:06:58 -0700
commita3defbe5c337dbc6da911f8cc49ae3cc3b49b453 (patch)
tree0971645887ef2848ad4f7bc86d2204aacb748de9 /fs/binfmt_elf.c
parentb35a35b556f5e6b7993ad0baf20173e75c09ce8c (diff)
downloadlwn-a3defbe5c337dbc6da911f8cc49ae3cc3b49b453.tar.gz
lwn-a3defbe5c337dbc6da911f8cc49ae3cc3b49b453.zip
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>
Diffstat (limited to 'fs/binfmt_elf.c')
-rw-r--r--fs/binfmt_elf.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index dd0fdfc56d38..21ac5ee4b43f 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -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)
- load_bias = 0;
+ /* 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