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author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-11-01 21:46:27 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-11-01 21:46:27 +0300 |
commit | 2d6bb6adb714b133db92ccd4bfc9c20f75f71f3f (patch) | |
tree | aef040a1ee4b8b6edc5a4fa2b3c6a2c48219f27a /arch/x86 | |
parent | 7c6c54b505b8aea1782ce6a6e8f3b8297d179937 (diff) | |
parent | 6fcde90466738b84a073e4f4d18c50015ee29fb2 (diff) | |
download | linux-2d6bb6adb714b133db92ccd4bfc9c20f75f71f3f.tar.xz |
Merge tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull stackleak gcc plugin from Kees Cook:
"Please pull this new GCC plugin, stackleak, for v4.20-rc1. This plugin
was ported from grsecurity by Alexander Popov. It provides efficient
stack content poisoning at syscall exit. This creates a defense
against at least two classes of flaws:
- Uninitialized stack usage. (We continue to work on improving the
compiler to do this in other ways: e.g. unconditional zero init was
proposed to GCC and Clang, and more plugin work has started too).
- Stack content exposure. By greatly reducing the lifetime of valid
stack contents, exposures via either direct read bugs or unknown
cache side-channels become much more difficult to exploit. This
complements the existing buddy and heap poisoning options, but
provides the coverage for stacks.
The x86 hooks are included in this series (which have been reviewed by
Ingo, Dave Hansen, and Thomas Gleixner). The arm64 hooks have already
been merged through the arm64 tree (written by Laura Abbott and
reviewed by Mark Rutland and Will Deacon).
With VLAs having been removed this release, there is no need for
alloca() protection, so it has been removed from the plugin"
* tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
arm64: Drop unneeded stackleak_check_alloca()
stackleak: Allow runtime disabling of kernel stack erasing
doc: self-protection: Add information about STACKLEAK feature
fs/proc: Show STACKLEAK metrics in the /proc file system
lkdtm: Add a test for STACKLEAK
gcc-plugins: Add STACKLEAK plugin for tracking the kernel stack
x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/Kconfig | 1 | ||||
-rw-r--r-- | arch/x86/entry/calling.h | 14 | ||||
-rw-r--r-- | arch/x86/entry/entry_32.S | 7 | ||||
-rw-r--r-- | arch/x86/entry/entry_64.S | 3 | ||||
-rw-r--r-- | arch/x86/entry/entry_64_compat.S | 5 |
5 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c51c989c19c0..ba7e3464ee92 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -129,6 +129,7 @@ config X86 select HAVE_ARCH_PREL32_RELOCATIONS select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_THREAD_STRUCT_WHITELIST + select HAVE_ARCH_STACKLEAK select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 708b46a54578..25e5a6bda8c3 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -329,8 +329,22 @@ For 32-bit we have the following conventions - kernel is built with #endif +.macro STACKLEAK_ERASE_NOCLOBBER +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + PUSH_AND_CLEAR_REGS + call stackleak_erase + POP_REGS +#endif +.endm + #endif /* CONFIG_X86_64 */ +.macro STACKLEAK_ERASE +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK + call stackleak_erase +#endif +.endm + /* * This does 'call enter_from_user_mode' unless we can avoid it based on * kernel config or using the static jump infrastructure. diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 687e47f8a796..d309f30cf7af 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -46,6 +46,8 @@ #include <asm/frame.h> #include <asm/nospec-branch.h> +#include "calling.h" + .section .entry.text, "ax" /* @@ -712,6 +714,7 @@ ENTRY(ret_from_fork) /* When we fork, we trace the syscall return in the child, too. */ movl %esp, %eax call syscall_return_slowpath + STACKLEAK_ERASE jmp restore_all /* kernel thread */ @@ -886,6 +889,8 @@ ENTRY(entry_SYSENTER_32) ALTERNATIVE "testl %eax, %eax; jz .Lsyscall_32_done", \ "jmp .Lsyscall_32_done", X86_FEATURE_XENPV + STACKLEAK_ERASE + /* Opportunistic SYSEXIT */ TRACE_IRQS_ON /* User mode traces as IRQs on. */ @@ -997,6 +1002,8 @@ ENTRY(entry_INT80_32) call do_int80_syscall_32 .Lsyscall_32_done: + STACKLEAK_ERASE + restore_all: TRACE_IRQS_IRET SWITCH_TO_ENTRY_STACK diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 4d7a2d9d44cf..ce25d84023c0 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -266,6 +266,8 @@ syscall_return_via_sysret: * We are on the trampoline stack. All regs except RDI are live. * We can do future final exit work right here. */ + STACKLEAK_ERASE_NOCLOBBER + SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi popq %rdi @@ -625,6 +627,7 @@ GLOBAL(swapgs_restore_regs_and_return_to_usermode) * We are on the trampoline stack. All regs except RDI are live. * We can do future final exit work right here. */ + STACKLEAK_ERASE_NOCLOBBER SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 7d0df78db727..8eaf8952c408 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -261,6 +261,11 @@ GLOBAL(entry_SYSCALL_compat_after_hwframe) /* Opportunistic SYSRET */ sysret32_from_system_call: + /* + * We are not going to return to userspace from the trampoline + * stack. So let's erase the thread stack right now. + */ + STACKLEAK_ERASE TRACE_IRQS_ON /* User mode traces as IRQs on. */ movq RBX(%rsp), %rbx /* pt_regs->rbx */ movq RBP(%rsp), %rbp /* pt_regs->rbp */ |