[PATCH v7 07/14] x86/cet/ibt: Add arch_prctl functions for IBT
From: Yu-cheng Yu <hidden>
Date: 2019-06-06 20:17:37
Also in:
linux-arch, linux-doc, linux-mm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Update ARCH_X86_CET_STATUS and ARCH_X86_CET_DISABLE to include
Indirect Branch Tracking features.
Introduce:
arch_prctl(ARCH_X86_CET_SET_LEGACY_BITMAP, unsigned long *addr)
Enable the Indirect Branch Tracking legacy code bitmap.
The parameter 'addr' is a pointer to a user buffer that has:
*addr = IBT bitmap base address
*(addr + 1) = IBT bitmap size
Signed-off-by: H.J. Lu <redacted>
Signed-off-by: Yu-cheng Yu <redacted>
---
arch/x86/include/uapi/asm/prctl.h | 2 ++
arch/x86/kernel/cet_prctl.c | 21 +++++++++++++++++++++
2 files changed, 23 insertions(+)
diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
index d962f0ec9ccf..5eb9aeb5c662 100644
--- a/arch/x86/include/uapi/asm/prctl.h
+++ b/arch/x86/include/uapi/asm/prctl.h@@ -18,5 +18,7 @@ #define ARCH_X86_CET_DISABLE 0x3002 #define ARCH_X86_CET_LOCK 0x3003 #define ARCH_X86_CET_ALLOC_SHSTK 0x3004 +#define ARCH_X86_CET_GET_LEGACY_BITMAP 0x3005 /* deprecated */ +#define ARCH_X86_CET_SET_LEGACY_BITMAP 0x3006 #endif /* _ASM_X86_PRCTL_H */
diff --git a/arch/x86/kernel/cet_prctl.c b/arch/x86/kernel/cet_prctl.c
index 9c9d4262b07e..b7f37bbc0dd3 100644
--- a/arch/x86/kernel/cet_prctl.c
+++ b/arch/x86/kernel/cet_prctl.c@@ -20,6 +20,8 @@ static int handle_get_status(unsigned long arg2) if (current->thread.cet.shstk_enabled) features |= GNU_PROPERTY_X86_FEATURE_1_SHSTK; + if (current->thread.cet.ibt_enabled) + features |= GNU_PROPERTY_X86_FEATURE_1_IBT; shstk_base = current->thread.cet.shstk_base; shstk_size = current->thread.cet.shstk_size;
@@ -55,6 +57,17 @@ static int handle_alloc_shstk(unsigned long arg2) return 0; } +static int handle_bitmap(unsigned long arg2) +{ + unsigned long addr, size; + + if (get_user(addr, (unsigned long __user *)arg2) || + get_user(size, (unsigned long __user *)arg2 + 1)) + return -EFAULT; + + return cet_setup_ibt_bitmap(addr, size); +} + int prctl_cet(int option, unsigned long arg2) { if (!cpu_x86_cet_enabled())
@@ -69,6 +82,8 @@ int prctl_cet(int option, unsigned long arg2) return -EPERM; if (arg2 & GNU_PROPERTY_X86_FEATURE_1_SHSTK) cet_disable_free_shstk(current); + if (arg2 & GNU_PROPERTY_X86_FEATURE_1_IBT) + cet_disable_ibt(); return 0;
@@ -79,6 +94,12 @@ int prctl_cet(int option, unsigned long arg2) case ARCH_X86_CET_ALLOC_SHSTK: return handle_alloc_shstk(arg2); + /* + * Allocate legacy bitmap and return address & size to user. + */ + case ARCH_X86_CET_SET_LEGACY_BITMAP: + return handle_bitmap(arg2); + default: return -EINVAL; }
--
2.17.1