diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-syscall-Sanitize-syscall-table-de-references-und.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-syscall-Sanitize-syscall-table-de-references-und.patch | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-syscall-Sanitize-syscall-table-de-references-und.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-syscall-Sanitize-syscall-table-de-references-und.patch new file mode 100644 index 00000000..8acd9616 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-syscall-Sanitize-syscall-table-de-references-und.patch @@ -0,0 +1,64 @@ +From 0c89c81045ecacb413a4cd61ec5187f7aa688074 Mon Sep 17 00:00:00 2001 +From: Dan Williams <dan.j.williams@intel.com> +Date: Mon, 29 Jan 2018 17:02:59 -0800 +Subject: [PATCH 32/42] x86/syscall: Sanitize syscall table de-references under + speculation + +(cherry picked from commit 2fbd7af5af8665d18bcefae3e9700be07e22b681) + +The syscall table base is a user controlled function pointer in kernel +space. Use array_index_nospec() to prevent any out of bounds speculation. + +While retpoline prevents speculating into a userspace directed target it +does not stop the pointer de-reference, the concern is leaking memory +relative to the syscall table base, by observing instruction cache +behavior. + +Reported-by: Linus Torvalds <torvalds@linux-foundation.org> +Signed-off-by: Dan Williams <dan.j.williams@intel.com> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Cc: linux-arch@vger.kernel.org +Cc: kernel-hardening@lists.openwall.com +Cc: gregkh@linuxfoundation.org +Cc: Andy Lutomirski <luto@kernel.org> +Cc: alan@linux.intel.com +Link: https://lkml.kernel.org/r/151727417984.33451.1216731042505722161.stgit@dwillia2-desk3.amr.corp.intel.com +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/entry/common.c | 5 ++++- + 1 file changed, 4 insertions(+), 1 deletion(-) + +diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c +index bd1d102..b0cd306 100644 +--- a/arch/x86/entry/common.c ++++ b/arch/x86/entry/common.c +@@ -20,6 +20,7 @@ + #include <linux/export.h> + #include <linux/context_tracking.h> + #include <linux/user-return-notifier.h> ++#include <linux/nospec.h> + #include <linux/uprobes.h> + + #include <asm/desc.h> +@@ -277,7 +278,8 @@ __visible void do_syscall_64(struct pt_regs *regs) + * regs->orig_ax, which changes the behavior of some syscalls. + */ + if (likely((nr & __SYSCALL_MASK) < NR_syscalls)) { +- regs->ax = sys_call_table[nr & __SYSCALL_MASK]( ++ nr = array_index_nospec(nr & __SYSCALL_MASK, NR_syscalls); ++ regs->ax = sys_call_table[nr]( + regs->di, regs->si, regs->dx, + regs->r10, regs->r8, regs->r9); + } +@@ -313,6 +315,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs) + } + + if (likely(nr < IA32_NR_syscalls)) { ++ nr = array_index_nospec(nr, IA32_NR_syscalls); + /* + * It's possible that a 32-bit syscall implementation + * takes a 64-bit parameter but nonetheless assumes that +-- +2.7.4 + |