[Xen-devel] [PATCH v4 14/15] xen: arm: Allow traps from 32 bit userspace on 64 bit hypervisors again

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

This removes the unconditional #undef injected in response to such
traps which was added by the fixes to CVE-2014-5147 / XSA-102 in
c0020e099702 "xen: arm: Handle traps from 32-bit userspace on 64-bit
kernel as undef", we now handle such traps correctly.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Reviewed-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/arm/traps.c |   12 ------------
 1 file changed, 12 deletions(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 1f52d27..04ade74 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2133,18 +2133,6 @@ asmlinkage void do_trap_hypervisor(struct cpu_user_regs 
*regs)
 
     enter_hypervisor_head(regs);
 
-    /*
-     * We currently do not handle 32-bit userspace on 64-bit kernels
-     * correctly (See XSA-102). Until that is resolved we treat any
-     * trap from 32-bit userspace on 64-bit kernel as undefined.
-     */
-    if ( !hyp_mode(regs) && is_64bit_domain(current->domain) &&
-         psr_mode_is_32bit(regs->cpsr) )
-    {
-        inject_undef_exception(regs, hsr.len);
-        return;
-    }
-
     switch (hsr.ec) {
     case HSR_EC_WFI_WFE:
         if ( !check_conditional_instr(regs, hsr) )
-- 
1.7.10.4


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