linux.git/arch/arm/kernel/traps.c, branch v4.19.205

ARM: 8948/1: Prevent OOB access in stacktrace

2020-10-01T11:14:31+00:00

[ Upstream commit 40ff1ddb5570284e039e0ff14d7a859a73dc3673 ]

The stacktrace code can read beyond the stack size, when it attempts to
read pt_regs from exception frames.

This can happen on normal, non-corrupt stacks.  Since the unwind
information in the extable is not correct for function prologues, the
unwinding code can return data from the stack which is not actually the
caller function address, and if in_entry_text() happens to succeed on
this value, we can end up reading data from outside the task's stack
when attempting to read pt_regs, since there is no bounds check.

Example:

 [<8010e729>] (unwind_backtrace) from [<8010a9c9>] (show_stack+0x11/0x14)
 [<8010a9c9>] (show_stack) from [<8057d8d7>] (dump_stack+0x87/0xac)
 [<8057d8d7>] (dump_stack) from [<8012271d>] (tasklet_action_common.constprop.4+0xa5/0xa8)
 [<8012271d>] (tasklet_action_common.constprop.4) from [<80102333>] (__do_softirq+0x11b/0x31c)
 [<80102333>] (__do_softirq) from [<80122485>] (irq_exit+0xad/0xd8)
 [<80122485>] (irq_exit) from [<8015f3d7>] (__handle_domain_irq+0x47/0x84)
 [<8015f3d7>] (__handle_domain_irq) from [<8036a523>] (gic_handle_irq+0x43/0x78)
 [<8036a523>] (gic_handle_irq) from [<80101a49>] (__irq_svc+0x69/0xb4)
 Exception stack(0xeb491f58 to 0xeb491fa0)
 1f40:                                                       7eb14794 00000000
 1f60: ffffffff 008dd32c 008dd324 ffffffff 008dd314 0000002a 801011e4 eb490000
 1f80: 0000002a 7eb1478c 50c5387d eb491fa8 80101001 8023d09c 40080033 ffffffff
 [<80101a49>] (__irq_svc) from [<8023d09c>] (do_pipe2+0x0/0xac)
 [<8023d09c>] (do_pipe2) from [] (0xffffffff)
 Exception stack(0xeb491fc8 to 0xeb492010)
 1fc0:                   008dd314 0000002a 00511ad8 008de4c8 7eb14790 7eb1478c
 1fe0: 00511e34 7eb14774 004c8557 76f44098 60080030 7eb14794 00000000 00000000
 2000: 00000001 00000000 ea846c00 ea847cc0

In this example, the stack limit is 0xeb492000, but 16 bytes outside the
stack have been read.

Fix it by adding bounds checks.

Signed-off-by: Vincent Whitchurch 
Signed-off-by: Russell King 
Signed-off-by: Sasha Levin

Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2018-06-04T22:23:48+00:00

Pull siginfo updates from Eric Biederman:
 "This set of changes close the known issues with setting si_code to an
  invalid value, and with not fully initializing struct siginfo. There
  remains work to do on nds32, arc, unicore32, powerpc, arm, arm64, ia64
  and x86 to get the code that generates siginfo into a simpler and more
  maintainable state. Most of that work involves refactoring the signal
  handling code and thus careful code review.

  Also not included is the work to shrink the in kernel version of
  struct siginfo. That depends on getting the number of places that
  directly manipulate struct siginfo under control, as it requires the
  introduction of struct kernel_siginfo for the in kernel things.

  Overall this set of changes looks like it is making good progress, and
  with a little luck I will be wrapping up the siginfo work next
  development cycle"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
  signal/sh: Stop gcc warning about an impossible case in do_divide_error
  signal/mips: Report FPE_FLTUNK for undiagnosed floating point exceptions
  signal/um: More carefully relay signals in relay_signal.
  signal: Extend siginfo_layout with SIL_FAULT_{MCEERR|BNDERR|PKUERR}
  signal: Remove unncessary #ifdef SEGV_PKUERR in 32bit compat code
  signal/signalfd: Add support for SIGSYS
  signal/signalfd: Remove __put_user from signalfd_copyinfo
  signal/xtensa: Use force_sig_fault where appropriate
  signal/xtensa: Consistenly use SIGBUS in do_unaligned_user
  signal/um: Use force_sig_fault where appropriate
  signal/sparc: Use force_sig_fault where appropriate
  signal/sparc: Use send_sig_fault where appropriate
  signal/sh: Use force_sig_fault where appropriate
  signal/s390: Use force_sig_fault where appropriate
  signal/riscv: Replace do_trap_siginfo with force_sig_fault
  signal/riscv: Use force_sig_fault where appropriate
  signal/parisc: Use force_sig_fault where appropriate
  signal/parisc: Use force_sig_mceerr where appropriate
  signal/openrisc: Use force_sig_fault where appropriate
  signal/nios2: Use force_sig_fault where appropriate
  ...

ARM: 8771/1: kprobes: Prohibit kprobes on do_undefinstr

2018-05-19T10:35:56+00:00

Prohibit kprobes on do_undefinstr because kprobes on
arm is implemented by undefined instruction. This means
if we probe do_undefinstr(), it can cause infinit
recursive exception.

Fixes: 24ba613c9d6c ("ARM kprobes: core code")
Signed-off-by: Masami Hiramatsu 
Cc: stable@vger.kernel.org
Signed-off-by: Russell King

signal: Ensure every siginfo we send has all bits initialized

2018-04-25T15:40:51+00:00

Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.

Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.

The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.

In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.

Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.

Signed-off-by: "Eric W. Biederman"

Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2018-02-02T17:50:51+00:00

Pull ARM updates from Russell King:

 - StrongARM SA1111 updates to modernise and remove cruft

 - Add StrongARM gpio drivers for board GPIOs

 - Verify size of zImage is what we expect to avoid issues with
   appended DTB

 - nommu updates from Vladimir Murzin

 - page table read-write-execute checking from Jinbum Park

 - Broadcom Brahma-B15 cache updates from Florian Fainelli

 - Avoid failure with kprobes test caused by inappropriately
   placed kprobes

 - Remove __memzero optimisation (which was incorrectly being
   used directly by some drivers)

* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (32 commits)
  ARM: 8745/1: get rid of __memzero()
  ARM: 8744/1: don't discard memblock for kexec
  ARM: 8743/1: bL_switcher: add MODULE_LICENSE tag
  ARM: 8742/1: Always use REFCOUNT_FULL
  ARM: 8741/1: B15: fix unused label warnings
  ARM: 8740/1: NOMMU: Make sure we do not hold stale data in mem[] array
  ARM: 8739/1: NOMMU: Setup VBAR/Hivecs for secondaries cores
  ARM: 8738/1: Disable CONFIG_DEBUG_VIRTUAL for NOMMU
  ARM: 8737/1: mm: dump: add checking for writable and executable
  ARM: 8736/1: mm: dump: make the page table dumping seq_file
  ARM: 8735/1: mm: dump: make page table dumping reusable
  ARM: sa1100/neponset: add GPIO drivers for control and modem registers
  ARM: sa1100/assabet: add BCR/BSR GPIO driver
  ARM: 8734/1: mm: idmap: Mark variables as ro_after_init
  ARM: 8733/1: hw_breakpoint: Mark variables as __ro_after_init
  ARM: 8732/1: NOMMU: Allow userspace to access background MPU region
  ARM: 8727/1: MAINTAINERS: Update brcmstb entries to cover B15 code
  ARM: 8728/1: B15: Register reboot notifier for KEXEC
  ARM: 8730/1: B15: Add suspend/resume hooks
  ARM: 8726/1: B15: Add CPU hotplug awareness
  ...

kernel/exit.c: export abort() to modules

2018-01-05T00:45:09+00:00

gcc -fisolate-erroneous-paths-dereference can generate calls to abort()
from modular code too.

[arnd@arndb.de: drop duplicate exports of abort()]
  Link: http://lkml.kernel.org/r/20180102103311.706364-1-arnd@arndb.de
Reported-by: Vineet Gupta 
Cc: Sudip Mukherjee 
Cc: Arnd Bergmann 
Cc: Alexey Brodkin 
Cc: Russell King 
Cc: Jose Abreu 
Signed-off-by: Andrew Morton 
Signed-off-by: Arnd Bergmann 
Signed-off-by: Linus Torvalds

ARM: probes: avoid adding kprobes to sensitive kernel-entry/exit code

2017-12-17T22:14:21+00:00

Avoid adding kprobes to any of the kernel entry/exit or startup
assembly code, or code in the identity-mapped region.  This code does
not conform to the standard C conventions, which means that the
expectations of the kprobes code is not forfilled.

Placing kprobes at some of these locations results in the kernel trying
to return to userspace addresses while retaining the CPU in kernel mode.

Tested-by: Naresh Kamboju 
Signed-off-by: Russell King

Merge branch 'devel-stable' into for-next

2017-11-08T19:42:47+00:00

ARM: 8720/1: ensure dump_instr() checks addr_limit

2017-11-06T12:00:38+00:00

When CONFIG_DEBUG_USER is enabled, it's possible for a user to
deliberately trigger dump_instr() with a chosen kernel address.

Let's avoid problems resulting from this by using get_user() rather than
__get_user(), ensuring that we don't erroneously access kernel memory.

So that we can use the same code to dump user instructions and kernel
instructions, the common dumping code is factored out to __dump_instr(),
with the fs manipulated appropriately in dump_instr() around calls to
this.

Signed-off-by: Mark Rutland 
Cc: stable@vger.kernel.org
Signed-off-by: Russell King

ARM: implement get_tls syscall

2017-09-10T23:31:46+00:00

When there is no dedicated register to hold the tp value and no MMU
to provide a fixed address kuser helper entry point, all that is
left as fallback is a syscall.

Signed-off-by: Nicolas Pitre 
Acked-by: Mickael GUENE 
Tested-by: Vincent Abriou 
Tested-by: Andras Szemzo