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Subject[17/59] ARM: Tighten check for allowable CPSR values
2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Russell King <rmk+kernel@arm.linux.org.uk>

commit 41e2e8fd34fff909a0e40129f6ac4233ecfa67a9 upstream.

Reviewed-by: Arve Hjønnevåg <arve@android.com>
Acked-by: Dima Zavin <dima@android.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/arm/include/asm/ptrace.h | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
--- a/arch/arm/include/asm/ptrace.h
+++ b/arch/arm/include/asm/ptrace.h
@@ -150,15 +150,24 @@ struct pt_regs {
*/
static inline int valid_user_regs(struct pt_regs *regs)
{
- if (user_mode(regs) && (regs->ARM_cpsr & PSR_I_BIT) == 0) {
- regs->ARM_cpsr &= ~(PSR_F_BIT | PSR_A_BIT);
- return 1;
+ unsigned long mode = regs->ARM_cpsr & MODE_MASK;
+
+ /*
+ * Always clear the F (FIQ) and A (delayed abort) bits
+ */
+ regs->ARM_cpsr &= ~(PSR_F_BIT | PSR_A_BIT);
+
+ if ((regs->ARM_cpsr & PSR_I_BIT) == 0) {
+ if (mode == USR_MODE)
+ return 1;
+ if (elf_hwcap & HWCAP_26BIT && mode == USR26_MODE)
+ return 1;
}

/*
* Force CPSR to something logical...
*/
- regs->ARM_cpsr &= PSR_f | PSR_s | (PSR_x & ~PSR_A_BIT) | PSR_T_BIT | MODE32_BIT;
+ regs->ARM_cpsr &= PSR_f | PSR_s | PSR_x | PSR_T_BIT | MODE32_BIT;
if (!(elf_hwcap & HWCAP_26BIT))
regs->ARM_cpsr |= USR_MODE;


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