diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0030-x86-uaccess-Use-__uaccess_begin_nospec-and-uaccess_t.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0030-x86-uaccess-Use-__uaccess_begin_nospec-and-uaccess_t.patch | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0030-x86-uaccess-Use-__uaccess_begin_nospec-and-uaccess_t.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0030-x86-uaccess-Use-__uaccess_begin_nospec-and-uaccess_t.patch new file mode 100644 index 00000000..fab4948d --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0030-x86-uaccess-Use-__uaccess_begin_nospec-and-uaccess_t.patch @@ -0,0 +1,196 @@ +From 268e7abcab638b44ca26107c32bf0c2df0a5b678 Mon Sep 17 00:00:00 2001 +From: Dan Williams <dan.j.williams@intel.com> +Date: Mon, 29 Jan 2018 17:02:49 -0800 +Subject: [PATCH 30/42] x86/uaccess: Use __uaccess_begin_nospec() and + uaccess_try_nospec + +(cherry picked from commit 304ec1b050310548db33063e567123fae8fd0301) + +Quoting Linus: + + I do think that it would be a good idea to very expressly document + the fact that it's not that the user access itself is unsafe. I do + agree that things like "get_user()" want to be protected, but not + because of any direct bugs or problems with get_user() and friends, + but simply because get_user() is an excellent source of a pointer + that is obviously controlled from a potentially attacking user + space. So it's a prime candidate for then finding _subsequent_ + accesses that can then be used to perturb the cache. + +__uaccess_begin_nospec() covers __get_user() and copy_from_iter() where the +limit check is far away from the user pointer de-reference. In those cases +a barrier_nospec() prevents speculation with a potential pointer to +privileged memory. uaccess_try_nospec covers get_user_try. + +Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> +Suggested-by: Andi Kleen <ak@linux.intel.com> +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: Kees Cook <keescook@chromium.org> +Cc: kernel-hardening@lists.openwall.com +Cc: gregkh@linuxfoundation.org +Cc: Al Viro <viro@zeniv.linux.org.uk> +Cc: alan@linux.intel.com +Link: https://lkml.kernel.org/r/151727416953.33451.10508284228526170604.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/include/asm/uaccess.h | 6 +++--- + arch/x86/include/asm/uaccess_32.h | 12 ++++++------ + arch/x86/include/asm/uaccess_64.h | 12 ++++++------ + arch/x86/lib/usercopy_32.c | 4 ++-- + 4 files changed, 17 insertions(+), 17 deletions(-) + +diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h +index c917703..f80021b 100644 +--- a/arch/x86/include/asm/uaccess.h ++++ b/arch/x86/include/asm/uaccess.h +@@ -428,7 +428,7 @@ do { \ + ({ \ + int __gu_err; \ + __inttype(*(ptr)) __gu_val; \ +- __uaccess_begin(); \ ++ __uaccess_begin_nospec(); \ + __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ + __uaccess_end(); \ + (x) = (__force __typeof__(*(ptr)))__gu_val; \ +@@ -538,7 +538,7 @@ struct __large_struct { unsigned long buf[100]; }; + * get_user_ex(...); + * } get_user_catch(err) + */ +-#define get_user_try uaccess_try ++#define get_user_try uaccess_try_nospec + #define get_user_catch(err) uaccess_catch(err) + + #define get_user_ex(x, ptr) do { \ +@@ -573,7 +573,7 @@ extern void __cmpxchg_wrong_size(void) + __typeof__(ptr) __uval = (uval); \ + __typeof__(*(ptr)) __old = (old); \ + __typeof__(*(ptr)) __new = (new); \ +- __uaccess_begin(); \ ++ __uaccess_begin_nospec(); \ + switch (size) { \ + case 1: \ + { \ +diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h +index 7d3bdd1..d6d2450 100644 +--- a/arch/x86/include/asm/uaccess_32.h ++++ b/arch/x86/include/asm/uaccess_32.h +@@ -102,17 +102,17 @@ __copy_from_user(void *to, const void __user *from, unsigned long n) + + switch (n) { + case 1: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_size(*(u8 *)to, from, 1, ret, 1); + __uaccess_end(); + return ret; + case 2: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_size(*(u16 *)to, from, 2, ret, 2); + __uaccess_end(); + return ret; + case 4: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_size(*(u32 *)to, from, 4, ret, 4); + __uaccess_end(); + return ret; +@@ -130,17 +130,17 @@ static __always_inline unsigned long __copy_from_user_nocache(void *to, + + switch (n) { + case 1: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_size(*(u8 *)to, from, 1, ret, 1); + __uaccess_end(); + return ret; + case 2: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_size(*(u16 *)to, from, 2, ret, 2); + __uaccess_end(); + return ret; + case 4: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_size(*(u32 *)to, from, 4, ret, 4); + __uaccess_end(); + return ret; +diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h +index 673059a..6e5cc08 100644 +--- a/arch/x86/include/asm/uaccess_64.h ++++ b/arch/x86/include/asm/uaccess_64.h +@@ -59,31 +59,31 @@ int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size) + return copy_user_generic(dst, (__force void *)src, size); + switch (size) { + case 1: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_asm(*(u8 *)dst, (u8 __user *)src, + ret, "b", "b", "=q", 1); + __uaccess_end(); + return ret; + case 2: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_asm(*(u16 *)dst, (u16 __user *)src, + ret, "w", "w", "=r", 2); + __uaccess_end(); + return ret; + case 4: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_asm(*(u32 *)dst, (u32 __user *)src, + ret, "l", "k", "=r", 4); + __uaccess_end(); + return ret; + case 8: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_asm(*(u64 *)dst, (u64 __user *)src, + ret, "q", "", "=r", 8); + __uaccess_end(); + return ret; + case 10: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_asm(*(u64 *)dst, (u64 __user *)src, + ret, "q", "", "=r", 10); + if (likely(!ret)) +@@ -93,7 +93,7 @@ int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size) + __uaccess_end(); + return ret; + case 16: +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + __get_user_asm(*(u64 *)dst, (u64 __user *)src, + ret, "q", "", "=r", 16); + if (likely(!ret)) +diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c +index 9b5fa0f..5c06dbf 100644 +--- a/arch/x86/lib/usercopy_32.c ++++ b/arch/x86/lib/usercopy_32.c +@@ -570,7 +570,7 @@ do { \ + unsigned long __copy_to_user_ll(void __user *to, const void *from, + unsigned long n) + { +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + if (movsl_is_ok(to, from, n)) + __copy_user(to, from, n); + else +@@ -627,7 +627,7 @@ EXPORT_SYMBOL(__copy_from_user_ll_nocache); + unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from, + unsigned long n) + { +- __uaccess_begin(); ++ __uaccess_begin_nospec(); + #ifdef CONFIG_X86_INTEL_USERCOPY + if (n > 64 && static_cpu_has(X86_FEATURE_XMM2)) + n = __copy_user_intel_nocache(to, from, n); +-- +2.7.4 + |