[PATCH 4.6 41/56] x86/power/64: Fix hibernation return address corruption

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.6 41/56] x86/power/64: Fix hibernation return address corruption
Date	2016-08-14 22:50 +0200
Message-ID	<s6aw2-4AX-49@gated-at.bofh.it> (permalink)
References	<s6amm-4wI-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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4.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Josh Poimboeuf <jpoimboe@redhat.com>

commit 4ce827b4cc58bec7952591b96cce2b28553e4d5b upstream.

In kernel bug 150021, a kernel panic was reported when restoring a
hibernate image.  Only a picture of the oops was reported, so I can't
paste the whole thing here.  But here are the most interesting parts:

  kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
  BUG: unable to handle kernel paging request at ffff8804615cfd78
  ...
  RIP: ffff8804615cfd78
  RSP: ffff8804615f0000
  RBP: ffff8804615cfdc0
  ...
  Call Trace:
   do_signal+0x23
   exit_to_usermode_loop+0x64
   ...

The RIP is on the same page as RBP, so it apparently started executing
on the stack.

The bug was bisected to commit ef0f3ed5a4ac (x86/asm/power: Create
stack frames in hibernate_asm_64.S), which in retrospect seems quite
dangerous, since that code saves and restores the stack pointer from a
global variable ('saved_context').

There are a lot of moving parts in the hibernate save and restore paths,
so I don't know exactly what caused the panic.  Presumably, a FRAME_END
was executed without the corresponding FRAME_BEGIN, or vice versa.  That
would corrupt the return address on the stack and would be consistent
with the details of the above panic.

[ rjw: One major problem is that by the time the FRAME_BEGIN in
  restore_registers() is executed, the stack pointer value may not
  be valid any more.  Namely, the stack area pointed to by it
  previously may have been overwritten by some image memory contents
  and that page frame may now be used for whatever different purpose
  it had been allocated for before hibernation.  In that case, the
  FRAME_BEGIN will corrupt that memory. ]

Instead of doing the frame pointer save/restore around the bounds of the
affected functions, just do it around the call to swsusp_save().

That has the same effect of ensuring that if swsusp_save() sleeps, the
frame pointers will be correct.  It's also a much more obviously safe
way to do it than the original patch.  And objtool still doesn't report
any warnings.

Fixes: ef0f3ed5a4ac (x86/asm/power: Create stack frames in hibernate_asm_64.S)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=150021
Reported-by: Andre Reinke <andre.reinke@mailbox.org>
Tested-by: Andre Reinke <andre.reinke@mailbox.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/power/hibernate_asm_64.S |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/arch/x86/power/hibernate_asm_64.S
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -24,7 +24,6 @@
 #include <asm/frame.h>
 
 ENTRY(swsusp_arch_suspend)
-	FRAME_BEGIN
 	movq	$saved_context, %rax
 	movq	%rsp, pt_regs_sp(%rax)
 	movq	%rbp, pt_regs_bp(%rax)
@@ -51,6 +50,7 @@ ENTRY(swsusp_arch_suspend)
 	movq	%cr3, %rax
 	movq	%rax, restore_cr3(%rip)
 
+	FRAME_BEGIN
 	call swsusp_save
 	FRAME_END
 	ret
@@ -111,7 +111,6 @@ ENTRY(core_restore_code)
 	 */
 
 ENTRY(restore_registers)
-	FRAME_BEGIN
 	/* go back to the original page tables */
 	movq    %rbx, %cr3
 
@@ -152,6 +151,5 @@ ENTRY(restore_registers)
 	/* tell the hibernation core that we've just restored the memory */
 	movq	%rax, in_suspend(%rip)
 
-	FRAME_END
 	ret
 ENDPROC(restore_registers)

Thread

[PATCH 4.6 00/56] 4.6.7-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:40 +0200
  [PATCH 4.6 56/56] ext4: fix reference counting bug on block allocation error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 02/56] libnvdimm, pfn, dax: fix initialization vs autodetect for mode + alignment Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 28/56] x86/xen, pat: Remove PAT table init code from Xen Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 35/56] mm: memcontrol: fix memcg id ref counter on swap charge move Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 06/56] bonding: set carrier off for devices created through netlink Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 34/56] mm: memcontrol: fix swap counter leak on swapout from offline cgroup Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 32/56] powerpc/eeh: Fix invalid cached PE primary bus Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 39/56] radix-tree: account nodes to memcg only if explicitly requested Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 45/56] Revert "mm, mempool: only set __GFP_NOMEMALLOC if there are free elements" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 41/56] x86/power/64: Fix hibernation return address corruption Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 22/56] random: strengthen input validation for RNDADDTOENTCNT Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 54/56] ext4: validate s_reserved_gdt_blocks on mount Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 37/56] block: fix use-after-free in seq file Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 51/56] ext4: check for extents that wrap around Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 27/56] x86/mtrr: Fix PAT init handling when MTRR is disabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 05/56] tcp: enable per-socket rate limiting of all challenge acks Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 25/56] x86/mm/pat: Replace cpu_has_pat with boot_cpu_has() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 21/56] regulator: qcom_smd: Remove list_voltage callback for rpm_smps_ldo_ops_fixed Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 47/56] Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 50/56] serial: mvebu-uart: free the IRQ in ->shutdown() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 53/56] ext4: dont call ext4_should_journal_data() on the journal inode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 46/56] fs/dcache.c: avoid soft-lockup in dput() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 48/56] crypto: gcm - Filter out async ghash if necessary Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 09/56] bridge: Fix incorrect re-injection of LLDP packets Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 30/56] x86/mm/pat: Fix BUG_ON() in mmap_mem() on QEMU/i386 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 38/56] sysv, ipc: fix security-layer leaking Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 44/56] fuse: fix wrong assignment of ->flags in fuse_send_init() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 18/56] IB/hfi1: Correct issues with sc5 computation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 16/56] arm: oabi compat: add missing access checks Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 17/56] KEYS: 64-bit MIPS needs to use compat_sys_keyctl for 32-bit userspace Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 22:50 +0200
  [PATCH 4.6 42/56] fuse: fsync() did not return IO errors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 36/56] x86/syscalls/64: Add compat_sys_keyctl for 32-bit userspace Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 29/56] x86/pat: Document the PAT initialization sequence Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 40/56] x86/microcode: Fix suspend to RAM with builtin microcode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 33/56] powerpc/bpf/jit: Disable classic BPF JIT on ppc64le Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 26/56] x86/mtrr: Fix Xorg crashes in Qemu sessions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 23/56] x86/mm/pat: Add support of non-default PAT MSR setting Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 52/56] ext4: fix deadlock during page writeback Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 55/56] ext4: short-cut orphan cleanup on error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 31/56] udf: Prevent stack overflow on corrupted filesystem mount Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 43/56] fuse: fuse_flush must check mapping->flags for errors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 49/56] crypto: scatterwalk - Fix test in scatterwalk_done Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:00 +0200
  [PATCH 4.6 20/56] apparmor: fix ref count leak when profile sha1 hash is read Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:10 +0200
  [PATCH 4.6 04/56] tcp: make challenge acks less predictable Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:10 +0200
  [PATCH 4.6 03/56] ppp: defer netns reference release for ppp channel Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:10 +0200
  [PATCH 4.6 19/56] IB/hfi1: Fix deadlock with txreq allocation slow path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:10 +0200
  [PATCH 4.6 08/56] vlan: use a valid default mtu value for vlan over macsec Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:10 +0200
  [PATCH 4.6 07/56] net: bgmac: Fix infinite loop in bgmac_dma_tx_add() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:10 +0200
  [PATCH 4.6 24/56] x86/mm/pat: Add pat_disable() interface Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-08-14 23:10 +0200
  Re: [PATCH 4.6 00/56] 4.6.7-stable review Guenter Roeck <linux@roeck-us.net> - 2016-08-15 15:10 +0200
  Re: [PATCH 4.6 00/56] 4.6.7-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-08-16 06:10 +0200

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