ARM: 6878/1: fix personality flag propagation across an exec

Our SET_PERSONALITY() implementation was overwriting all existing
personality flags, including ADDR_NO_RANDOMIZE, making them unavailable
to processes being exec'd after a call to personality() in user space.
This prevents the gdb test suite from running successfully.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 12 insertions, 5 deletions

diff --git a/arch/arm/kernel/elf.c b/arch/arm/kernel/elf.c
index d4a0da1e48f4..9b05c6a0dcea 100644
--- a/arch/arm/kernel/elf.c
+++ b/arch/arm/kernel/elf.c
@@ -40,15 +40,22 @@ EXPORT_SYMBOL(elf_check_arch);
 void elf_set_personality(const struct elf32_hdr *x)
 {
         unsigned int eflags = x->e_flags;
-        unsigned int personality = PER_LINUX_32BIT;
+        unsigned int personality = current->personality & ~PER_MASK;
+
+        /*
+         * We only support Linux ELF executables, so always set the
+         * personality to LINUX.
+         */
+        personality |= PER_LINUX;
 
         /*
          * APCS-26 is only valid for OABI executables
          */
-        if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN) {
-                if (eflags & EF_ARM_APCS_26)
-                        personality = PER_LINUX;
-        }
+        if ((eflags & EF_ARM_EABI_MASK) == EF_ARM_EABI_UNKNOWN &&
+            (eflags & EF_ARM_APCS_26))
+                personality &= ~ADDR_LIMIT_32BIT;
+        else
+                personality |= ADDR_LIMIT_32BIT;
 
         set_personality(personality);