diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0042-nospec-Kill-array_index_nospec_mask_check.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0042-nospec-Kill-array_index_nospec_mask_check.patch | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0042-nospec-Kill-array_index_nospec_mask_check.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0042-nospec-Kill-array_index_nospec_mask_check.patch new file mode 100644 index 00000000..d74a2ba7 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0042-nospec-Kill-array_index_nospec_mask_check.patch @@ -0,0 +1,85 @@ +From ae4a53f80d78b49ff776956f133cb59344aa10e9 Mon Sep 17 00:00:00 2001 +From: Dan Williams <dan.j.williams@intel.com> +Date: Fri, 16 Feb 2018 13:20:42 -0800 +Subject: [PATCH 42/93] nospec: Kill array_index_nospec_mask_check() + +commit 1d91c1d2c80cb70e2e553845e278b87a960c04da upstream. + +There are multiple problems with the dynamic sanity checking in +array_index_nospec_mask_check(): + +* It causes unnecessary overhead in the 32-bit case since integer sized + @index values will no longer cause the check to be compiled away like + in the 64-bit case. + +* In the 32-bit case it may trigger with user controllable input when + the expectation is that should only trigger during development of new + kernel enabling. + +* The macro reuses the input parameter in multiple locations which is + broken if someone passes an expression like 'index++' to + array_index_nospec(). + +Reported-by: Linus Torvalds <torvalds@linux-foundation.org> +Signed-off-by: Dan Williams <dan.j.williams@intel.com> +Cc: Andy Lutomirski <luto@kernel.org> +Cc: Arjan van de Ven <arjan@linux.intel.com> +Cc: Borislav Petkov <bp@alien8.de> +Cc: Dave Hansen <dave.hansen@linux.intel.com> +Cc: David Woodhouse <dwmw2@infradead.org> +Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Cc: Josh Poimboeuf <jpoimboe@redhat.com> +Cc: Peter Zijlstra <peterz@infradead.org> +Cc: Thomas Gleixner <tglx@linutronix.de> +Cc: Will Deacon <will.deacon@arm.com> +Cc: linux-arch@vger.kernel.org +Link: http://lkml.kernel.org/r/151881604278.17395.6605847763178076520.stgit@dwillia2-desk3.amr.corp.intel.com +Signed-off-by: Ingo Molnar <mingo@kernel.org> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + include/linux/nospec.h | 22 +--------------------- + 1 file changed, 1 insertion(+), 21 deletions(-) + +diff --git a/include/linux/nospec.h b/include/linux/nospec.h +index 132e3f5..172a19d 100644 +--- a/include/linux/nospec.h ++++ b/include/linux/nospec.h +@@ -30,26 +30,6 @@ static inline unsigned long array_index_mask_nospec(unsigned long index, + #endif + + /* +- * Warn developers about inappropriate array_index_nospec() usage. +- * +- * Even if the CPU speculates past the WARN_ONCE branch, the +- * sign bit of @index is taken into account when generating the +- * mask. +- * +- * This warning is compiled out when the compiler can infer that +- * @index and @size are less than LONG_MAX. +- */ +-#define array_index_mask_nospec_check(index, size) \ +-({ \ +- if (WARN_ONCE(index > LONG_MAX || size > LONG_MAX, \ +- "array_index_nospec() limited to range of [0, LONG_MAX]\n")) \ +- _mask = 0; \ +- else \ +- _mask = array_index_mask_nospec(index, size); \ +- _mask; \ +-}) +- +-/* + * array_index_nospec - sanitize an array index after a bounds check + * + * For a code sequence like: +@@ -67,7 +47,7 @@ static inline unsigned long array_index_mask_nospec(unsigned long index, + ({ \ + typeof(index) _i = (index); \ + typeof(size) _s = (size); \ +- unsigned long _mask = array_index_mask_nospec_check(_i, _s); \ ++ unsigned long _mask = array_index_mask_nospec(_i, _s); \ + \ + BUILD_BUG_ON(sizeof(_i) > sizeof(long)); \ + BUILD_BUG_ON(sizeof(_s) > sizeof(long)); \ +-- +2.7.4 + |