From 5a17f040fa332e71a45ca9ff02d6979d9176a423 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 26 Oct 2022 16:31:11 -0700 Subject: cred: Do not default to init_cred in prepare_kernel_cred() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A common exploit pattern for ROP attacks is to abuse prepare_kernel_cred() in order to construct escalated privileges[1]. Instead of providing a short-hand argument (NULL) to the "daemon" argument to indicate using init_cred as the base cred, require that "daemon" is always set to an actual task. Replace all existing callers that were passing NULL with &init_task. Future attacks will need to have sufficiently powerful read/write primitives to have found an appropriately privileged task and written it to the ROP stack as an argument to succeed, which is similarly difficult to the prior effort needed to escalate privileges before struct cred existed: locate the current cred and overwrite the uid member. This has the added benefit of meaning that prepare_kernel_cred() can no longer exceed the privileges of the init task, which may have changed from the original init_cred (e.g. dropping capabilities from the bounding set). [1] https://google.com/search?q=commit_creds(prepare_kernel_cred(0)) Cc: "Eric W. Biederman" Cc: David Howells Cc: "Rafael J. Wysocki" Cc: Steve French Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Namjae Jeon Cc: Trond Myklebust Cc: Anna Schumaker Cc: Chuck Lever Cc: Jeff Layton Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: "Michal Koutný" Cc: Peter Zijlstra Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Cc: linux-nfs@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Acked-by: Luis Chamberlain Reviewed-by: Sergey Senozhatsky Acked-by: Russ Weight Acked-by: Greg Kroah-Hartman Acked-by: Paulo Alcantara (SUSE) Link: https://lore.kernel.org/r/20221026232943.never.775-kees@kernel.org --- drivers/base/firmware_loader/main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index 7c3590fd97c2..017c4cdb219e 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -821,7 +821,7 @@ _request_firmware(const struct firmware **firmware_p, const char *name, * called by a driver when serving an unrelated request from userland, we use * the kernel credentials to read the file. */ - kern_cred = prepare_kernel_cred(NULL); + kern_cred = prepare_kernel_cred(&init_task); if (!kern_cred) { ret = -ENOMEM; goto out; -- cgit v1.2.3 From cd536db050993f7c220a6cfb01de5356032b6f8e Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 18 Oct 2022 02:10:11 -0700 Subject: dma-buf: Proactively round up to kmalloc bucket size MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Instead of discovering the kmalloc bucket size _after_ allocation, round up proactively so the allocation is explicitly made for the full size, allowing the compiler to correctly reason about the resulting size of the buffer through the existing __alloc_size() hint. Cc: Sumit Semwal Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Reviewed-by: Christian König Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221018090858.never.941-kees@kernel.org --- drivers/dma-buf/dma-resv.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index e3885c90a3ac..1c76aed8e262 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -98,12 +98,17 @@ static void dma_resv_list_set(struct dma_resv_list *list, static struct dma_resv_list *dma_resv_list_alloc(unsigned int max_fences) { struct dma_resv_list *list; + size_t size; - list = kmalloc(struct_size(list, table, max_fences), GFP_KERNEL); + /* Round up to the next kmalloc bucket size. */ + size = kmalloc_size_roundup(struct_size(list, table, max_fences)); + + list = kmalloc(size, GFP_KERNEL); if (!list) return NULL; - list->max_fences = (ksize(list) - offsetof(typeof(*list), table)) / + /* Given the resulting bucket size, recalculated max_fences. */ + list->max_fences = (size - offsetof(typeof(*list), table)) / sizeof(*list->table); return list; -- cgit v1.2.3 From 4b21d25bf519c9487935a664886956bb18f04f6d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 24 Oct 2022 23:11:25 +0300 Subject: overflow: Introduce overflows_type() and castable_to_type() Implement a robust overflows_type() macro to test if a variable or constant value would overflow another variable or type. This can be used as a constant expression for static_assert() (which requires a constant expression[1][2]) when used on constant values. This must be constructed manually, since __builtin_add_overflow() does not produce a constant expression[3]. Additionally adds castable_to_type(), similar to __same_type(), but for checking if a constant value would overflow if cast to a given type. Add unit tests for overflows_type(), __same_type(), and castable_to_type() to the existing KUnit "overflow" test: [16:03:33] ================== overflow (21 subtests) ================== ... [16:03:33] [PASSED] overflows_type_test [16:03:33] [PASSED] same_type_test [16:03:33] [PASSED] castable_to_type_test [16:03:33] ==================== [PASSED] overflow ===================== [16:03:33] ============================================================ [16:03:33] Testing complete. Ran 21 tests: passed: 21 [16:03:33] Elapsed time: 24.022s total, 0.002s configuring, 22.598s building, 0.767s running [1] https://en.cppreference.com/w/c/language/_Static_assert [2] C11 standard (ISO/IEC 9899:2011): 6.7.10 Static assertions [3] https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html 6.56 Built-in Functions to Perform Arithmetic with Overflow Checking Built-in Function: bool __builtin_add_overflow (type1 a, type2 b, Cc: Luc Van Oostenryck Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Tom Rix Cc: Daniel Latypov Cc: Vitor Massaru Iha Cc: "Gustavo A. R. Silva" Cc: Jani Nikula Cc: Mauro Carvalho Chehab Cc: linux-hardening@vger.kernel.org Cc: llvm@lists.linux.dev Co-developed-by: Gwan-gyeong Mun Signed-off-by: Gwan-gyeong Mun Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221024201125.1416422-1-gwan-gyeong.mun@intel.com --- drivers/gpu/drm/i915/i915_user_extensions.c | 2 +- drivers/gpu/drm/i915/i915_utils.h | 4 - include/linux/compiler.h | 1 + include/linux/overflow.h | 47 ++++ lib/Makefile | 1 + lib/overflow_kunit.c | 381 ++++++++++++++++++++++++++++ 6 files changed, 431 insertions(+), 5 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/i915/i915_user_extensions.c b/drivers/gpu/drm/i915/i915_user_extensions.c index c822d0aafd2d..e3f808372c47 100644 --- a/drivers/gpu/drm/i915/i915_user_extensions.c +++ b/drivers/gpu/drm/i915/i915_user_extensions.c @@ -51,7 +51,7 @@ int i915_user_extensions(struct i915_user_extension __user *ext, return err; if (get_user(next, &ext->next_extension) || - overflows_type(next, ext)) + overflows_type(next, uintptr_t)) return -EFAULT; ext = u64_to_user_ptr(next); diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h index 6c14d13364bf..67a66d4d5c70 100644 --- a/drivers/gpu/drm/i915/i915_utils.h +++ b/drivers/gpu/drm/i915/i915_utils.h @@ -111,10 +111,6 @@ bool i915_error_injected(void); #define range_overflows_end_t(type, start, size, max) \ range_overflows_end((type)(start), (type)(size), (type)(max)) -/* Note we don't consider signbits :| */ -#define overflows_type(x, T) \ - (sizeof(x) > sizeof(T) && (x) >> BITS_PER_TYPE(T)) - #define ptr_mask_bits(ptr, n) ({ \ unsigned long __v = (unsigned long)(ptr); \ (typeof(ptr))(__v & -BIT(n)); \ diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 973a1bfd7ef5..947a60b801db 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -236,6 +236,7 @@ static inline void *offset_to_ptr(const int *off) * bool and also pointer types. */ #define is_signed_type(type) (((type)(-1)) < (__force type)1) +#define is_unsigned_type(type) (!is_signed_type(type)) /* * This is needed in functions which generate the stack canary, see diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 1d3be1a2204c..0e33b5cbdb9f 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -128,6 +128,53 @@ static inline bool __must_check __must_check_overflow(bool overflow) (*_d >> _to_shift) != _a); \ })) +#define __overflows_type_constexpr(x, T) ( \ + is_unsigned_type(typeof(x)) ? \ + (x) > type_max(typeof(T)) : \ + is_unsigned_type(typeof(T)) ? \ + (x) < 0 || (x) > type_max(typeof(T)) : \ + (x) < type_min(typeof(T)) || (x) > type_max(typeof(T))) + +#define __overflows_type(x, T) ({ \ + typeof(T) v = 0; \ + check_add_overflow((x), v, &v); \ +}) + +/** + * overflows_type - helper for checking the overflows between value, variables, + * or data type + * + * @n: source constant value or variable to be checked + * @T: destination variable or data type proposed to store @x + * + * Compares the @x expression for whether or not it can safely fit in + * the storage of the type in @T. @x and @T can have different types. + * If @x is a constant expression, this will also resolve to a constant + * expression. + * + * Returns: true if overflow can occur, false otherwise. + */ +#define overflows_type(n, T) \ + __builtin_choose_expr(__is_constexpr(n), \ + __overflows_type_constexpr(n, T), \ + __overflows_type(n, T)) + +/** + * castable_to_type - like __same_type(), but also allows for casted literals + * + * @n: variable or constant value + * @T: variable or data type + * + * Unlike the __same_type() macro, this allows a constant value as the + * first argument. If this value would not overflow into an assignment + * of the second argument's type, it returns true. Otherwise, this falls + * back to __same_type(). + */ +#define castable_to_type(n, T) \ + __builtin_choose_expr(__is_constexpr(n), \ + !__overflows_type_constexpr(n, T), \ + __same_type(n, T)) + /** * size_mul() - Calculate size_t multiplication with saturation at SIZE_MAX * @factor1: first factor diff --git a/lib/Makefile b/lib/Makefile index 77c7951c8cf0..322178b9f7fb 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -374,6 +374,7 @@ obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o obj-$(CONFIG_MEMCPY_KUNIT_TEST) += memcpy_kunit.o obj-$(CONFIG_IS_SIGNED_TYPE_KUNIT_TEST) += is_signed_type_kunit.o +CFLAGS_overflow_kunit.o = $(call cc-disable-warning, tautological-constant-out-of-range-compare) obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o CFLAGS_stackinit_kunit.o += $(call cc-disable-warning, switch-unreachable) obj-$(CONFIG_STACKINIT_KUNIT_TEST) += stackinit_kunit.o diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c index b8556a2e7bb1..dcd3ba102db6 100644 --- a/lib/overflow_kunit.c +++ b/lib/overflow_kunit.c @@ -736,6 +736,384 @@ static void overflow_size_helpers_test(struct kunit *test) #undef check_one_size_helper } +static void overflows_type_test(struct kunit *test) +{ + int count = 0; + unsigned int var; + +#define __TEST_OVERFLOWS_TYPE(func, arg1, arg2, of) do { \ + bool __of = func(arg1, arg2); \ + KUNIT_EXPECT_EQ_MSG(test, __of, of, \ + "expected " #func "(" #arg1 ", " #arg2 " to%s overflow\n",\ + of ? "" : " not"); \ + count++; \ +} while (0) + +/* Args are: first type, second type, value, overflow expected */ +#define TEST_OVERFLOWS_TYPE(__t1, __t2, v, of) do { \ + __t1 t1 = (v); \ + __t2 t2; \ + __TEST_OVERFLOWS_TYPE(__overflows_type, t1, t2, of); \ + __TEST_OVERFLOWS_TYPE(__overflows_type, t1, __t2, of); \ + __TEST_OVERFLOWS_TYPE(__overflows_type_constexpr, t1, t2, of); \ + __TEST_OVERFLOWS_TYPE(__overflows_type_constexpr, t1, __t2, of);\ +} while (0) + + TEST_OVERFLOWS_TYPE(u8, u8, U8_MAX, false); + TEST_OVERFLOWS_TYPE(u8, u16, U8_MAX, false); + TEST_OVERFLOWS_TYPE(u8, s8, U8_MAX, true); + TEST_OVERFLOWS_TYPE(u8, s8, S8_MAX, false); + TEST_OVERFLOWS_TYPE(u8, s8, (u8)S8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u8, s16, U8_MAX, false); + TEST_OVERFLOWS_TYPE(s8, u8, S8_MAX, false); + TEST_OVERFLOWS_TYPE(s8, u8, -1, true); + TEST_OVERFLOWS_TYPE(s8, u8, S8_MIN, true); + TEST_OVERFLOWS_TYPE(s8, u16, S8_MAX, false); + TEST_OVERFLOWS_TYPE(s8, u16, -1, true); + TEST_OVERFLOWS_TYPE(s8, u16, S8_MIN, true); + TEST_OVERFLOWS_TYPE(s8, u32, S8_MAX, false); + TEST_OVERFLOWS_TYPE(s8, u32, -1, true); + TEST_OVERFLOWS_TYPE(s8, u32, S8_MIN, true); +#if BITS_PER_LONG == 64 + TEST_OVERFLOWS_TYPE(s8, u64, S8_MAX, false); + TEST_OVERFLOWS_TYPE(s8, u64, -1, true); + TEST_OVERFLOWS_TYPE(s8, u64, S8_MIN, true); +#endif + TEST_OVERFLOWS_TYPE(s8, s8, S8_MAX, false); + TEST_OVERFLOWS_TYPE(s8, s8, S8_MIN, false); + TEST_OVERFLOWS_TYPE(s8, s16, S8_MAX, false); + TEST_OVERFLOWS_TYPE(s8, s16, S8_MIN, false); + TEST_OVERFLOWS_TYPE(u16, u8, U8_MAX, false); + TEST_OVERFLOWS_TYPE(u16, u8, (u16)U8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u16, u8, U16_MAX, true); + TEST_OVERFLOWS_TYPE(u16, s8, S8_MAX, false); + TEST_OVERFLOWS_TYPE(u16, s8, (u16)S8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u16, s8, U16_MAX, true); + TEST_OVERFLOWS_TYPE(u16, s16, S16_MAX, false); + TEST_OVERFLOWS_TYPE(u16, s16, (u16)S16_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u16, s16, U16_MAX, true); + TEST_OVERFLOWS_TYPE(u16, u32, U16_MAX, false); + TEST_OVERFLOWS_TYPE(u16, s32, U16_MAX, false); + TEST_OVERFLOWS_TYPE(s16, u8, U8_MAX, false); + TEST_OVERFLOWS_TYPE(s16, u8, (s16)U8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s16, u8, -1, true); + TEST_OVERFLOWS_TYPE(s16, u8, S16_MIN, true); + TEST_OVERFLOWS_TYPE(s16, u16, S16_MAX, false); + TEST_OVERFLOWS_TYPE(s16, u16, -1, true); + TEST_OVERFLOWS_TYPE(s16, u16, S16_MIN, true); + TEST_OVERFLOWS_TYPE(s16, u32, S16_MAX, false); + TEST_OVERFLOWS_TYPE(s16, u32, -1, true); + TEST_OVERFLOWS_TYPE(s16, u32, S16_MIN, true); +#if BITS_PER_LONG == 64 + TEST_OVERFLOWS_TYPE(s16, u64, S16_MAX, false); + TEST_OVERFLOWS_TYPE(s16, u64, -1, true); + TEST_OVERFLOWS_TYPE(s16, u64, S16_MIN, true); +#endif + TEST_OVERFLOWS_TYPE(s16, s8, S8_MAX, false); + TEST_OVERFLOWS_TYPE(s16, s8, S8_MIN, false); + TEST_OVERFLOWS_TYPE(s16, s8, (s16)S8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s16, s8, (s16)S8_MIN - 1, true); + TEST_OVERFLOWS_TYPE(s16, s8, S16_MAX, true); + TEST_OVERFLOWS_TYPE(s16, s8, S16_MIN, true); + TEST_OVERFLOWS_TYPE(s16, s16, S16_MAX, false); + TEST_OVERFLOWS_TYPE(s16, s16, S16_MIN, false); + TEST_OVERFLOWS_TYPE(s16, s32, S16_MAX, false); + TEST_OVERFLOWS_TYPE(s16, s32, S16_MIN, false); + TEST_OVERFLOWS_TYPE(u32, u8, U8_MAX, false); + TEST_OVERFLOWS_TYPE(u32, u8, (u32)U8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u32, u8, U32_MAX, true); + TEST_OVERFLOWS_TYPE(u32, s8, S8_MAX, false); + TEST_OVERFLOWS_TYPE(u32, s8, (u32)S8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u32, s8, U32_MAX, true); + TEST_OVERFLOWS_TYPE(u32, u16, U16_MAX, false); + TEST_OVERFLOWS_TYPE(u32, u16, U16_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u32, u16, U32_MAX, true); + TEST_OVERFLOWS_TYPE(u32, s16, S16_MAX, false); + TEST_OVERFLOWS_TYPE(u32, s16, (u32)S16_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u32, s16, U32_MAX, true); + TEST_OVERFLOWS_TYPE(u32, u32, U32_MAX, false); + TEST_OVERFLOWS_TYPE(u32, s32, S32_MAX, false); + TEST_OVERFLOWS_TYPE(u32, s32, U32_MAX, true); + TEST_OVERFLOWS_TYPE(u32, s32, (u32)S32_MAX + 1, true); +#if BITS_PER_LONG == 64 + TEST_OVERFLOWS_TYPE(u32, u64, U32_MAX, false); + TEST_OVERFLOWS_TYPE(u32, s64, U32_MAX, false); +#endif + TEST_OVERFLOWS_TYPE(s32, u8, U8_MAX, false); + TEST_OVERFLOWS_TYPE(s32, u8, (s32)U8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s32, u16, S32_MAX, true); + TEST_OVERFLOWS_TYPE(s32, u8, -1, true); + TEST_OVERFLOWS_TYPE(s32, u8, S32_MIN, true); + TEST_OVERFLOWS_TYPE(s32, u16, U16_MAX, false); + TEST_OVERFLOWS_TYPE(s32, u16, (s32)U16_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s32, u16, S32_MAX, true); + TEST_OVERFLOWS_TYPE(s32, u16, -1, true); + TEST_OVERFLOWS_TYPE(s32, u16, S32_MIN, true); + TEST_OVERFLOWS_TYPE(s32, u32, S32_MAX, false); + TEST_OVERFLOWS_TYPE(s32, u32, -1, true); + TEST_OVERFLOWS_TYPE(s32, u32, S32_MIN, true); +#if BITS_PER_LONG == 64 + TEST_OVERFLOWS_TYPE(s32, u64, S32_MAX, false); + TEST_OVERFLOWS_TYPE(s32, u64, -1, true); + TEST_OVERFLOWS_TYPE(s32, u64, S32_MIN, true); +#endif + TEST_OVERFLOWS_TYPE(s32, s8, S8_MAX, false); + TEST_OVERFLOWS_TYPE(s32, s8, S8_MIN, false); + TEST_OVERFLOWS_TYPE(s32, s8, (s32)S8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s32, s8, (s32)S8_MIN - 1, true); + TEST_OVERFLOWS_TYPE(s32, s8, S32_MAX, true); + TEST_OVERFLOWS_TYPE(s32, s8, S32_MIN, true); + TEST_OVERFLOWS_TYPE(s32, s16, S16_MAX, false); + TEST_OVERFLOWS_TYPE(s32, s16, S16_MIN, false); + TEST_OVERFLOWS_TYPE(s32, s16, (s32)S16_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s32, s16, (s32)S16_MIN - 1, true); + TEST_OVERFLOWS_TYPE(s32, s16, S32_MAX, true); + TEST_OVERFLOWS_TYPE(s32, s16, S32_MIN, true); + TEST_OVERFLOWS_TYPE(s32, s32, S32_MAX, false); + TEST_OVERFLOWS_TYPE(s32, s32, S32_MIN, false); +#if BITS_PER_LONG == 64 + TEST_OVERFLOWS_TYPE(s32, s64, S32_MAX, false); + TEST_OVERFLOWS_TYPE(s32, s64, S32_MIN, false); + TEST_OVERFLOWS_TYPE(u64, u8, U64_MAX, true); + TEST_OVERFLOWS_TYPE(u64, u8, U8_MAX, false); + TEST_OVERFLOWS_TYPE(u64, u8, (u64)U8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u64, u16, U64_MAX, true); + TEST_OVERFLOWS_TYPE(u64, u16, U16_MAX, false); + TEST_OVERFLOWS_TYPE(u64, u16, (u64)U16_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u64, u32, U64_MAX, true); + TEST_OVERFLOWS_TYPE(u64, u32, U32_MAX, false); + TEST_OVERFLOWS_TYPE(u64, u32, (u64)U32_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u64, u64, U64_MAX, false); + TEST_OVERFLOWS_TYPE(u64, s8, S8_MAX, false); + TEST_OVERFLOWS_TYPE(u64, s8, (u64)S8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u64, s8, U64_MAX, true); + TEST_OVERFLOWS_TYPE(u64, s16, S16_MAX, false); + TEST_OVERFLOWS_TYPE(u64, s16, (u64)S16_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u64, s16, U64_MAX, true); + TEST_OVERFLOWS_TYPE(u64, s32, S32_MAX, false); + TEST_OVERFLOWS_TYPE(u64, s32, (u64)S32_MAX + 1, true); + TEST_OVERFLOWS_TYPE(u64, s32, U64_MAX, true); + TEST_OVERFLOWS_TYPE(u64, s64, S64_MAX, false); + TEST_OVERFLOWS_TYPE(u64, s64, U64_MAX, true); + TEST_OVERFLOWS_TYPE(u64, s64, (u64)S64_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s64, u8, S64_MAX, true); + TEST_OVERFLOWS_TYPE(s64, u8, S64_MIN, true); + TEST_OVERFLOWS_TYPE(s64, u8, -1, true); + TEST_OVERFLOWS_TYPE(s64, u8, U8_MAX, false); + TEST_OVERFLOWS_TYPE(s64, u8, (s64)U8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s64, u16, S64_MAX, true); + TEST_OVERFLOWS_TYPE(s64, u16, S64_MIN, true); + TEST_OVERFLOWS_TYPE(s64, u16, -1, true); + TEST_OVERFLOWS_TYPE(s64, u16, U16_MAX, false); + TEST_OVERFLOWS_TYPE(s64, u16, (s64)U16_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s64, u32, S64_MAX, true); + TEST_OVERFLOWS_TYPE(s64, u32, S64_MIN, true); + TEST_OVERFLOWS_TYPE(s64, u32, -1, true); + TEST_OVERFLOWS_TYPE(s64, u32, U32_MAX, false); + TEST_OVERFLOWS_TYPE(s64, u32, (s64)U32_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s64, u64, S64_MAX, false); + TEST_OVERFLOWS_TYPE(s64, u64, S64_MIN, true); + TEST_OVERFLOWS_TYPE(s64, u64, -1, true); + TEST_OVERFLOWS_TYPE(s64, s8, S8_MAX, false); + TEST_OVERFLOWS_TYPE(s64, s8, S8_MIN, false); + TEST_OVERFLOWS_TYPE(s64, s8, (s64)S8_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s64, s8, (s64)S8_MIN - 1, true); + TEST_OVERFLOWS_TYPE(s64, s8, S64_MAX, true); + TEST_OVERFLOWS_TYPE(s64, s16, S16_MAX, false); + TEST_OVERFLOWS_TYPE(s64, s16, S16_MIN, false); + TEST_OVERFLOWS_TYPE(s64, s16, (s64)S16_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s64, s16, (s64)S16_MIN - 1, true); + TEST_OVERFLOWS_TYPE(s64, s16, S64_MAX, true); + TEST_OVERFLOWS_TYPE(s64, s32, S32_MAX, false); + TEST_OVERFLOWS_TYPE(s64, s32, S32_MIN, false); + TEST_OVERFLOWS_TYPE(s64, s32, (s64)S32_MAX + 1, true); + TEST_OVERFLOWS_TYPE(s64, s32, (s64)S32_MIN - 1, true); + TEST_OVERFLOWS_TYPE(s64, s32, S64_MAX, true); + TEST_OVERFLOWS_TYPE(s64, s64, S64_MAX, false); + TEST_OVERFLOWS_TYPE(s64, s64, S64_MIN, false); +#endif + + /* Check for macro side-effects. */ + var = INT_MAX - 1; + __TEST_OVERFLOWS_TYPE(__overflows_type, var++, int, false); + __TEST_OVERFLOWS_TYPE(__overflows_type, var++, int, false); + __TEST_OVERFLOWS_TYPE(__overflows_type, var++, int, true); + var = INT_MAX - 1; + __TEST_OVERFLOWS_TYPE(overflows_type, var++, int, false); + __TEST_OVERFLOWS_TYPE(overflows_type, var++, int, false); + __TEST_OVERFLOWS_TYPE(overflows_type, var++, int, true); + + kunit_info(test, "%d overflows_type() tests finished\n", count); +#undef TEST_OVERFLOWS_TYPE +#undef __TEST_OVERFLOWS_TYPE +} + +static void same_type_test(struct kunit *test) +{ + int count = 0; + int var; + +#define TEST_SAME_TYPE(t1, t2, same) do { \ + typeof(t1) __t1h = type_max(t1); \ + typeof(t1) __t1l = type_min(t1); \ + typeof(t2) __t2h = type_max(t2); \ + typeof(t2) __t2l = type_min(t2); \ + KUNIT_EXPECT_EQ(test, true, __same_type(t1, __t1h)); \ + KUNIT_EXPECT_EQ(test, true, __same_type(t1, __t1l)); \ + KUNIT_EXPECT_EQ(test, true, __same_type(__t1h, t1)); \ + KUNIT_EXPECT_EQ(test, true, __same_type(__t1l, t1)); \ + KUNIT_EXPECT_EQ(test, true, __same_type(t2, __t2h)); \ + KUNIT_EXPECT_EQ(test, true, __same_type(t2, __t2l)); \ + KUNIT_EXPECT_EQ(test, true, __same_type(__t2h, t2)); \ + KUNIT_EXPECT_EQ(test, true, __same_type(__t2l, t2)); \ + KUNIT_EXPECT_EQ(test, same, __same_type(t1, t2)); \ + KUNIT_EXPECT_EQ(test, same, __same_type(t2, __t1h)); \ + KUNIT_EXPECT_EQ(test, same, __same_type(t2, __t1l)); \ + KUNIT_EXPECT_EQ(test, same, __same_type(__t1h, t2)); \ + KUNIT_EXPECT_EQ(test, same, __same_type(__t1l, t2)); \ + KUNIT_EXPECT_EQ(test, same, __same_type(t1, __t2h)); \ + KUNIT_EXPECT_EQ(test, same, __same_type(t1, __t2l)); \ + KUNIT_EXPECT_EQ(test, same, __same_type(__t2h, t1)); \ + KUNIT_EXPECT_EQ(test, same, __same_type(__t2l, t1)); \ +} while (0) + +#if BITS_PER_LONG == 64 +# define TEST_SAME_TYPE64(base, t, m) TEST_SAME_TYPE(base, t, m) +#else +# define TEST_SAME_TYPE64(base, t, m) do { } while (0) +#endif + +#define TEST_TYPE_SETS(base, mu8, mu16, mu32, ms8, ms16, ms32, mu64, ms64) \ +do { \ + TEST_SAME_TYPE(base, u8, mu8); \ + TEST_SAME_TYPE(base, u16, mu16); \ + TEST_SAME_TYPE(base, u32, mu32); \ + TEST_SAME_TYPE(base, s8, ms8); \ + TEST_SAME_TYPE(base, s16, ms16); \ + TEST_SAME_TYPE(base, s32, ms32); \ + TEST_SAME_TYPE64(base, u64, mu64); \ + TEST_SAME_TYPE64(base, s64, ms64); \ +} while (0) + + TEST_TYPE_SETS(u8, true, false, false, false, false, false, false, false); + TEST_TYPE_SETS(u16, false, true, false, false, false, false, false, false); + TEST_TYPE_SETS(u32, false, false, true, false, false, false, false, false); + TEST_TYPE_SETS(s8, false, false, false, true, false, false, false, false); + TEST_TYPE_SETS(s16, false, false, false, false, true, false, false, false); + TEST_TYPE_SETS(s32, false, false, false, false, false, true, false, false); +#if BITS_PER_LONG == 64 + TEST_TYPE_SETS(u64, false, false, false, false, false, false, true, false); + TEST_TYPE_SETS(s64, false, false, false, false, false, false, false, true); +#endif + + /* Check for macro side-effects. */ + var = 4; + KUNIT_EXPECT_EQ(test, var, 4); + KUNIT_EXPECT_TRUE(test, __same_type(var++, int)); + KUNIT_EXPECT_EQ(test, var, 4); + KUNIT_EXPECT_TRUE(test, __same_type(int, var++)); + KUNIT_EXPECT_EQ(test, var, 4); + KUNIT_EXPECT_TRUE(test, __same_type(var++, var++)); + KUNIT_EXPECT_EQ(test, var, 4); + + kunit_info(test, "%d __same_type() tests finished\n", count); + +#undef TEST_TYPE_SETS +#undef TEST_SAME_TYPE64 +#undef TEST_SAME_TYPE +} + +static void castable_to_type_test(struct kunit *test) +{ + int count = 0; + +#define TEST_CASTABLE_TO_TYPE(arg1, arg2, pass) do { \ + bool __pass = castable_to_type(arg1, arg2); \ + KUNIT_EXPECT_EQ_MSG(test, __pass, pass, \ + "expected castable_to_type(" #arg1 ", " #arg2 ") to%s pass\n",\ + pass ? "" : " not"); \ + count++; \ +} while (0) + + TEST_CASTABLE_TO_TYPE(16, u8, true); + TEST_CASTABLE_TO_TYPE(16, u16, true); + TEST_CASTABLE_TO_TYPE(16, u32, true); + TEST_CASTABLE_TO_TYPE(16, s8, true); + TEST_CASTABLE_TO_TYPE(16, s16, true); + TEST_CASTABLE_TO_TYPE(16, s32, true); + TEST_CASTABLE_TO_TYPE(-16, s8, true); + TEST_CASTABLE_TO_TYPE(-16, s16, true); + TEST_CASTABLE_TO_TYPE(-16, s32, true); +#if BITS_PER_LONG == 64 + TEST_CASTABLE_TO_TYPE(16, u64, true); + TEST_CASTABLE_TO_TYPE(-16, s64, true); +#endif + +#define TEST_CASTABLE_TO_TYPE_VAR(width) do { \ + u ## width u ## width ## var = 0; \ + s ## width s ## width ## var = 0; \ + \ + /* Constant expressions that fit types. */ \ + TEST_CASTABLE_TO_TYPE(type_max(u ## width), u ## width, true); \ + TEST_CASTABLE_TO_TYPE(type_min(u ## width), u ## width, true); \ + TEST_CASTABLE_TO_TYPE(type_max(u ## width), u ## width ## var, true); \ + TEST_CASTABLE_TO_TYPE(type_min(u ## width), u ## width ## var, true); \ + TEST_CASTABLE_TO_TYPE(type_max(s ## width), s ## width, true); \ + TEST_CASTABLE_TO_TYPE(type_min(s ## width), s ## width, true); \ + TEST_CASTABLE_TO_TYPE(type_max(s ## width), s ## width ## var, true); \ + TEST_CASTABLE_TO_TYPE(type_min(u ## width), s ## width ## var, true); \ + /* Constant expressions that do not fit types. */ \ + TEST_CASTABLE_TO_TYPE(type_max(u ## width), s ## width, false); \ + TEST_CASTABLE_TO_TYPE(type_max(u ## width), s ## width ## var, false); \ + TEST_CASTABLE_TO_TYPE(type_min(s ## width), u ## width, false); \ + TEST_CASTABLE_TO_TYPE(type_min(s ## width), u ## width ## var, false); \ + /* Non-constant expression with mismatched type. */ \ + TEST_CASTABLE_TO_TYPE(s ## width ## var, u ## width, false); \ + TEST_CASTABLE_TO_TYPE(u ## width ## var, s ## width, false); \ +} while (0) + +#define TEST_CASTABLE_TO_TYPE_RANGE(width) do { \ + unsigned long big = U ## width ## _MAX; \ + signed long small = S ## width ## _MIN; \ + u ## width u ## width ## var = 0; \ + s ## width s ## width ## var = 0; \ + \ + /* Constant expression in range. */ \ + TEST_CASTABLE_TO_TYPE(U ## width ## _MAX, u ## width, true); \ + TEST_CASTABLE_TO_TYPE(U ## width ## _MAX, u ## width ## var, true); \ + TEST_CASTABLE_TO_TYPE(S ## width ## _MIN, s ## width, true); \ + TEST_CASTABLE_TO_TYPE(S ## width ## _MIN, s ## width ## var, true); \ + /* Constant expression out of range. */ \ + TEST_CASTABLE_TO_TYPE((unsigned long)U ## width ## _MAX + 1, u ## width, false); \ + TEST_CASTABLE_TO_TYPE((unsigned long)U ## width ## _MAX + 1, u ## width ## var, false); \ + TEST_CASTABLE_TO_TYPE((signed long)S ## width ## _MIN - 1, s ## width, false); \ + TEST_CASTABLE_TO_TYPE((signed long)S ## width ## _MIN - 1, s ## width ## var, false); \ + /* Non-constant expression with mismatched type. */ \ + TEST_CASTABLE_TO_TYPE(big, u ## width, false); \ + TEST_CASTABLE_TO_TYPE(big, u ## width ## var, false); \ + TEST_CASTABLE_TO_TYPE(small, s ## width, false); \ + TEST_CASTABLE_TO_TYPE(small, s ## width ## var, false); \ +} while (0) + + TEST_CASTABLE_TO_TYPE_VAR(8); + TEST_CASTABLE_TO_TYPE_VAR(16); + TEST_CASTABLE_TO_TYPE_VAR(32); +#if BITS_PER_LONG == 64 + TEST_CASTABLE_TO_TYPE_VAR(64); +#endif + + TEST_CASTABLE_TO_TYPE_RANGE(8); + TEST_CASTABLE_TO_TYPE_RANGE(16); +#if BITS_PER_LONG == 64 + TEST_CASTABLE_TO_TYPE_RANGE(32); +#endif + kunit_info(test, "%d castable_to_type() tests finished\n", count); + +#undef TEST_CASTABLE_TO_TYPE_RANGE +#undef TEST_CASTABLE_TO_TYPE_VAR +#undef TEST_CASTABLE_TO_TYPE +} + static struct kunit_case overflow_test_cases[] = { KUNIT_CASE(u8_u8__u8_overflow_test), KUNIT_CASE(s8_s8__s8_overflow_test), @@ -755,6 +1133,9 @@ static struct kunit_case overflow_test_cases[] = { KUNIT_CASE(shift_nonsense_test), KUNIT_CASE(overflow_allocation_test), KUNIT_CASE(overflow_size_helpers_test), + KUNIT_CASE(overflows_type_test), + KUNIT_CASE(same_type_test), + KUNIT_CASE(castable_to_type_test), {} }; -- cgit v1.2.3 From 96d845a67b7e406cfed7880a724c8ca6121e022e Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Wed, 2 Nov 2022 08:42:15 -0700 Subject: drm/fsl-dcu: Fix return type of fsl_dcu_drm_connector_mode_valid() With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A proposed warning in clang aims to catch these at compile time, which reveals: drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c:74:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_connector *, struct drm_display_mode *)' with an expression of type 'int (struct drm_connector *, struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] .mode_valid = fsl_dcu_drm_connector_mode_valid, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1 error generated. ->mode_valid() in 'struct drm_connector_helper_funcs' expects a return type of 'enum drm_mode_status', not 'int'. Adjust the return type of fsl_dcu_drm_connector_mode_valid() to match the prototype's to resolve the warning and CFI failure. Link: https://github.com/ClangBuiltLinux/linux/issues/1750 Reported-by: Sami Tolvanen Signed-off-by: Nathan Chancellor Reviewed-by: Kees Cook Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221102154215.78059-1-nathan@kernel.org --- drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c index 4d4a715b429d..2c2b92324a2e 100644 --- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c +++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c @@ -60,8 +60,9 @@ static int fsl_dcu_drm_connector_get_modes(struct drm_connector *connector) return drm_panel_get_modes(fsl_connector->panel, connector); } -static int fsl_dcu_drm_connector_mode_valid(struct drm_connector *connector, - struct drm_display_mode *mode) +static enum drm_mode_status +fsl_dcu_drm_connector_mode_valid(struct drm_connector *connector, + struct drm_display_mode *mode) { if (mode->hdisplay & 0xf) return MODE_ERROR; -- cgit v1.2.3 From 0ad811cc08a937d875cbad0149c1bab17f84ba05 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Wed, 2 Nov 2022 08:56:23 -0700 Subject: drm/sti: Fix return type of sti_{dvo,hda,hdmi}_connector_mode_valid() With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A proposed warning in clang aims to catch these at compile time, which reveals: drivers/gpu/drm/sti/sti_hda.c:637:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_connector *, struct drm_display_mode *)' with an expression of type 'int (struct drm_connector *, struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] .mode_valid = sti_hda_connector_mode_valid, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/sti/sti_dvo.c:376:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_connector *, struct drm_display_mode *)' with an expression of type 'int (struct drm_connector *, struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] .mode_valid = sti_dvo_connector_mode_valid, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/sti/sti_hdmi.c:1035:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_connector *, struct drm_display_mode *)' with an expression of type 'int (struct drm_connector *, struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] .mode_valid = sti_hdmi_connector_mode_valid, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ->mode_valid() in 'struct drm_connector_helper_funcs' expects a return type of 'enum drm_mode_status', not 'int'. Adjust the return type of sti_{dvo,hda,hdmi}_connector_mode_valid() to match the prototype's to resolve the warning and CFI failure. Link: https://github.com/ClangBuiltLinux/linux/issues/1750 Signed-off-by: Nathan Chancellor Reviewed-by: Kees Cook Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221102155623.3042869-1-nathan@kernel.org --- drivers/gpu/drm/sti/sti_dvo.c | 5 +++-- drivers/gpu/drm/sti/sti_hda.c | 5 +++-- drivers/gpu/drm/sti/sti_hdmi.c | 5 +++-- 3 files changed, 9 insertions(+), 6 deletions(-) (limited to 'drivers') diff --git a/drivers/gpu/drm/sti/sti_dvo.c b/drivers/gpu/drm/sti/sti_dvo.c index b6ee8a82e656..076d5f30a09c 100644 --- a/drivers/gpu/drm/sti/sti_dvo.c +++ b/drivers/gpu/drm/sti/sti_dvo.c @@ -346,8 +346,9 @@ static int sti_dvo_connector_get_modes(struct drm_connector *connector) #define CLK_TOLERANCE_HZ 50 -static int sti_dvo_connector_mode_valid(struct drm_connector *connector, - struct drm_display_mode *mode) +static enum drm_mode_status +sti_dvo_connector_mode_valid(struct drm_connector *connector, + struct drm_display_mode *mode) { int target = mode->clock * 1000; int target_min = target - CLK_TOLERANCE_HZ; diff --git a/drivers/gpu/drm/sti/sti_hda.c b/drivers/gpu/drm/sti/sti_hda.c index 03cc401ed593..a53b5a15c2a9 100644 --- a/drivers/gpu/drm/sti/sti_hda.c +++ b/drivers/gpu/drm/sti/sti_hda.c @@ -601,8 +601,9 @@ static int sti_hda_connector_get_modes(struct drm_connector *connector) #define CLK_TOLERANCE_HZ 50 -static int sti_hda_connector_mode_valid(struct drm_connector *connector, - struct drm_display_mode *mode) +static enum drm_mode_status +sti_hda_connector_mode_valid(struct drm_connector *connector, + struct drm_display_mode *mode) { int target = mode->clock * 1000; int target_min = target - CLK_TOLERANCE_HZ; diff --git a/drivers/gpu/drm/sti/sti_hdmi.c b/drivers/gpu/drm/sti/sti_hdmi.c index cb82622877d2..09e0cadb6368 100644 --- a/drivers/gpu/drm/sti/sti_hdmi.c +++ b/drivers/gpu/drm/sti/sti_hdmi.c @@ -1004,8 +1004,9 @@ fail: #define CLK_TOLERANCE_HZ 50 -static int sti_hdmi_connector_mode_valid(struct drm_connector *connector, - struct drm_display_mode *mode) +static enum drm_mode_status +sti_hdmi_connector_mode_valid(struct drm_connector *connector, + struct drm_display_mode *mode) { int target = mode->clock * 1000; int target_min = target - CLK_TOLERANCE_HZ; -- cgit v1.2.3