diff options
Diffstat (limited to 'system/xen/xsa/xsa183-unstable.patch')
| -rw-r--r-- | system/xen/xsa/xsa183-unstable.patch | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/system/xen/xsa/xsa183-unstable.patch b/system/xen/xsa/xsa183-unstable.patch new file mode 100644 index 0000000000000..573c530112c24 --- /dev/null +++ b/system/xen/xsa/xsa183-unstable.patch @@ -0,0 +1,75 @@ +From 2fd4f34058fb5f87fbd80978dbd2cb458aff565d Mon Sep 17 00:00:00 2001 +From: Andrew Cooper <andrew.cooper3@citrix.com> +Date: Wed, 15 Jun 2016 18:32:14 +0100 +Subject: [PATCH] x86/entry: Avoid SMAP violation in + compat_create_bounce_frame() + +A 32bit guest kernel might be running on user mappings. +compat_create_bounce_frame() must whitelist its guest accesses to avoid +risking a SMAP violation. + +For both variants of create_bounce_frame(), re-blacklist user accesses if +execution exits via an exception table redirection. + +This is XSA-183 / CVE-2016-6259 + +Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> +Reviewed-by: George Dunlap <george.dunlap@citrix.com> +Reviewed-by: Jan Beulich <jbeulich@suse.com> +--- +v2: + * Include CLAC on the exit paths from compat_create_bounce_frame which occur + from faults attempting to load %fs + * Reposition ASM_STAC to avoid breaking the macro-op fusion of test/jz +--- + xen/arch/x86/x86_64/compat/entry.S | 3 +++ + xen/arch/x86/x86_64/entry.S | 2 ++ + 2 files changed, 5 insertions(+) + +diff --git a/xen/arch/x86/x86_64/compat/entry.S b/xen/arch/x86/x86_64/compat/entry.S +index 7f02afd..e80c53c 100644 +--- a/xen/arch/x86/x86_64/compat/entry.S ++++ b/xen/arch/x86/x86_64/compat/entry.S +@@ -318,6 +318,7 @@ ENTRY(compat_int80_direct_trap) + compat_create_bounce_frame: + ASSERT_INTERRUPTS_ENABLED + mov %fs,%edi ++ ASM_STAC + testb $2,UREGS_cs+8(%rsp) + jz 1f + /* Push new frame at registered guest-OS stack base. */ +@@ -364,6 +365,7 @@ compat_create_bounce_frame: + movl TRAPBOUNCE_error_code(%rdx),%eax + .Lft8: movl %eax,%fs:(%rsi) # ERROR CODE + 1: ++ ASM_CLAC + /* Rewrite our stack frame and return to guest-OS mode. */ + /* IA32 Ref. Vol. 3: TF, VM, RF and NT flags are cleared on trap. */ + andl $~(X86_EFLAGS_VM|X86_EFLAGS_RF|\ +@@ -403,6 +405,7 @@ compat_crash_page_fault_4: + addl $4,%esi + compat_crash_page_fault: + .Lft14: mov %edi,%fs ++ ASM_CLAC + movl %esi,%edi + call show_page_walk + jmp dom_crash_sync_extable +diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S +index ad8c64c..f7178cd 100644 +--- a/xen/arch/x86/x86_64/entry.S ++++ b/xen/arch/x86/x86_64/entry.S +@@ -420,9 +420,11 @@ domain_crash_page_fault_16: + domain_crash_page_fault_8: + addq $8,%rsi + domain_crash_page_fault: ++ ASM_CLAC + movq %rsi,%rdi + call show_page_walk + ENTRY(dom_crash_sync_extable) ++ ASM_CLAC + # Get out of the guest-save area of the stack. + GET_STACK_END(ax) + leaq STACK_CPUINFO_FIELD(guest_cpu_user_regs)(%rax),%rsp +-- +2.1.4 + |