From e1be43d9b5d0d1310dbd90185a8e5c7145dde40f Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Sat, 18 Sep 2021 15:17:53 -0700 Subject: overflow: Implement size_t saturating arithmetic helpers In order to perform more open-coded replacements of common allocation size arithmetic, the kernel needs saturating (SIZE_MAX) helpers for multiplication, addition, and subtraction. For example, it is common in allocators, especially on realloc, to add to an existing size: p = krealloc(map->patch, sizeof(struct reg_sequence) * (map->patch_regs + num_regs), GFP_KERNEL); There is no existing saturating replacement for this calculation, and just leaving the addition open coded inside array_size() could potentially overflow as well. For example, an overflow in an expression for a size_t argument might wrap to zero: array_size(anything, something_at_size_max + 1) == 0 Introduce size_mul(), size_add(), and size_sub() helpers that implicitly promote arguments to size_t and saturated calculations for use in allocations. With these helpers it is also possible to redefine array_size(), array3_size(), flex_array_size(), and struct_size() in terms of the new helpers. As with the check_*_overflow() helpers, the new helpers use __must_check, though what is really desired is a way to make sure that assignment is only to a size_t lvalue. Without this, it's still possible to introduce overflow/underflow via type conversion (i.e. from size_t to int). Enforcing this will currently need to be left to static analysis or future use of -Wconversion. Additionally update the overflow unit tests to force runtime evaluation for the pathological cases. Cc: Rasmus Villemoes Cc: Gustavo A. R. Silva Cc: Nathan Chancellor Cc: Jason Gunthorpe Cc: Nick Desaulniers Cc: Leon Romanovsky Cc: Keith Busch Cc: Len Baker Signed-off-by: Kees Cook --- include/linux/overflow.h | 110 +++++++++++++++++++++++++++++------------------ 1 file changed, 69 insertions(+), 41 deletions(-) (limited to 'include/linux/overflow.h') diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 4669632bd72b..59d7228104d0 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -118,81 +118,94 @@ static inline bool __must_check __must_check_overflow(bool overflow) })) /** - * array_size() - Calculate size of 2-dimensional array. - * - * @a: dimension one - * @b: dimension two + * size_mul() - Calculate size_t multiplication with saturation at SIZE_MAX * - * Calculates size of 2-dimensional array: @a * @b. + * @factor1: first factor + * @factor2: second factor * - * Returns: number of bytes needed to represent the array or SIZE_MAX on - * overflow. + * Returns: calculate @factor1 * @factor2, both promoted to size_t, + * with any overflow causing the return value to be SIZE_MAX. The + * lvalue must be size_t to avoid implicit type conversion. */ -static inline __must_check size_t array_size(size_t a, size_t b) +static inline size_t __must_check size_mul(size_t factor1, size_t factor2) { size_t bytes; - if (check_mul_overflow(a, b, &bytes)) + if (check_mul_overflow(factor1, factor2, &bytes)) return SIZE_MAX; return bytes; } /** - * array3_size() - Calculate size of 3-dimensional array. + * size_add() - Calculate size_t addition with saturation at SIZE_MAX * - * @a: dimension one - * @b: dimension two - * @c: dimension three - * - * Calculates size of 3-dimensional array: @a * @b * @c. + * @addend1: first addend + * @addend2: second addend * - * Returns: number of bytes needed to represent the array or SIZE_MAX on - * overflow. + * Returns: calculate @addend1 + @addend2, both promoted to size_t, + * with any overflow causing the return value to be SIZE_MAX. The + * lvalue must be size_t to avoid implicit type conversion. */ -static inline __must_check size_t array3_size(size_t a, size_t b, size_t c) +static inline size_t __must_check size_add(size_t addend1, size_t addend2) { size_t bytes; - if (check_mul_overflow(a, b, &bytes)) - return SIZE_MAX; - if (check_mul_overflow(bytes, c, &bytes)) + if (check_add_overflow(addend1, addend2, &bytes)) return SIZE_MAX; return bytes; } -/* - * Compute a*b+c, returning SIZE_MAX on overflow. Internal helper for - * struct_size() below. +/** + * size_sub() - Calculate size_t subtraction with saturation at SIZE_MAX + * + * @minuend: value to subtract from + * @subtrahend: value to subtract from @minuend + * + * Returns: calculate @minuend - @subtrahend, both promoted to size_t, + * with any overflow causing the return value to be SIZE_MAX. For + * composition with the size_add() and size_mul() helpers, neither + * argument may be SIZE_MAX (or the result with be forced to SIZE_MAX). + * The lvalue must be size_t to avoid implicit type conversion. */ -static inline __must_check size_t __ab_c_size(size_t a, size_t b, size_t c) +static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) { size_t bytes; - if (check_mul_overflow(a, b, &bytes)) - return SIZE_MAX; - if (check_add_overflow(bytes, c, &bytes)) + if (minuend == SIZE_MAX || subtrahend == SIZE_MAX || + check_sub_overflow(minuend, subtrahend, &bytes)) return SIZE_MAX; return bytes; } /** - * struct_size() - Calculate size of structure with trailing array. - * @p: Pointer to the structure. - * @member: Name of the array member. - * @count: Number of elements in the array. + * array_size() - Calculate size of 2-dimensional array. * - * Calculates size of memory needed for structure @p followed by an - * array of @count number of @member elements. + * @a: dimension one + * @b: dimension two * - * Return: number of bytes needed or SIZE_MAX on overflow. + * Calculates size of 2-dimensional array: @a * @b. + * + * Returns: number of bytes needed to represent the array or SIZE_MAX on + * overflow. */ -#define struct_size(p, member, count) \ - __ab_c_size(count, \ - sizeof(*(p)->member) + __must_be_array((p)->member),\ - sizeof(*(p))) +#define array_size(a, b) size_mul(a, b) + +/** + * array3_size() - Calculate size of 3-dimensional array. + * + * @a: dimension one + * @b: dimension two + * @c: dimension three + * + * Calculates size of 3-dimensional array: @a * @b * @c. + * + * Returns: number of bytes needed to represent the array or SIZE_MAX on + * overflow. + */ +#define array3_size(a, b, c) size_mul(size_mul(a, b), c) /** * flex_array_size() - Calculate size of a flexible array member @@ -208,7 +221,22 @@ static inline __must_check size_t __ab_c_size(size_t a, size_t b, size_t c) * Return: number of bytes needed or SIZE_MAX on overflow. */ #define flex_array_size(p, member, count) \ - array_size(count, \ - sizeof(*(p)->member) + __must_be_array((p)->member)) + size_mul(count, \ + sizeof(*(p)->member) + __must_be_array((p)->member)) + +/** + * struct_size() - Calculate size of structure with trailing flexible array. + * + * @p: Pointer to the structure. + * @member: Name of the array member. + * @count: Number of elements in the array. + * + * Calculates size of memory needed for structure @p followed by an + * array of @count number of @member elements. + * + * Return: number of bytes needed or SIZE_MAX on overflow. + */ +#define struct_size(p, member, count) \ + size_add(sizeof(*(p)), flex_array_size(p, member, count)) #endif /* __LINUX_OVERFLOW_H */ -- cgit v1.2.3 From 230f6fa2c1db6a3f3e668cfe95995ac8e6eee212 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 9 Feb 2022 16:40:41 -0800 Subject: overflow: Provide constant expression struct_size There have been cases where struct_size() (or flex_array_size()) needs to be calculated for an initializer, which requires it be a constant expression. This is possible when the "count" argument is a constant expression, so provide this ability for the helpers. Cc: Gustavo A. R. Silva Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Rasmus Villemoes Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Tested-by: Gustavo A. R. Silva Link: https://lore.kernel.org/lkml/20220210010407.GA701603@embeddedor --- include/linux/overflow.h | 10 +++++++--- lib/test_overflow.c | 26 +++++++++++++++++--------- 2 files changed, 24 insertions(+), 12 deletions(-) (limited to 'include/linux/overflow.h') diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 59d7228104d0..f1221d11f8e5 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -4,6 +4,7 @@ #include #include +#include /* * We need to compute the minimum and maximum values representable in a given @@ -221,8 +222,9 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) * Return: number of bytes needed or SIZE_MAX on overflow. */ #define flex_array_size(p, member, count) \ - size_mul(count, \ - sizeof(*(p)->member) + __must_be_array((p)->member)) + __builtin_choose_expr(__is_constexpr(count), \ + (count) * sizeof(*(p)->member) + __must_be_array((p)->member), \ + size_mul(count, sizeof(*(p)->member) + __must_be_array((p)->member))) /** * struct_size() - Calculate size of structure with trailing flexible array. @@ -237,6 +239,8 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) * Return: number of bytes needed or SIZE_MAX on overflow. */ #define struct_size(p, member, count) \ - size_add(sizeof(*(p)), flex_array_size(p, member, count)) + __builtin_choose_expr(__is_constexpr(count), \ + sizeof(*(p)) + flex_array_size(p, member, count), \ + size_add(sizeof(*(p)), flex_array_size(p, member, count))) #endif /* __LINUX_OVERFLOW_H */ diff --git a/lib/test_overflow.c b/lib/test_overflow.c index 712fb2351c27..f6530fce799d 100644 --- a/lib/test_overflow.c +++ b/lib/test_overflow.c @@ -602,10 +602,18 @@ struct __test_flex_array { static int __init test_overflow_size_helpers(void) { + /* Make sure struct_size() can be used in a constant expression. */ + u8 ce_array[struct_size((struct __test_flex_array *)0, data, 55)]; struct __test_flex_array *obj; int count = 0; int err = 0; int var; + volatile int unconst = 0; + + /* Verify constant expression against runtime version. */ + var = 55; + OPTIMIZER_HIDE_VAR(var); + err |= sizeof(ce_array) != struct_size(obj, data, var); #define check_one_size_helper(expected, func, args...) ({ \ bool __failure = false; \ @@ -663,28 +671,28 @@ static int __init test_overflow_size_helpers(void) flex_array_size, obj, data, var++); err |= check_one_size_helper(5 * sizeof(*obj->data), flex_array_size, obj, data, var++); - err |= check_one_size_helper(0, flex_array_size, obj, data, 0); + err |= check_one_size_helper(0, flex_array_size, obj, data, 0 + unconst); err |= check_one_size_helper(sizeof(*obj->data), - flex_array_size, obj, data, 1); + flex_array_size, obj, data, 1 + unconst); err |= check_one_size_helper(7 * sizeof(*obj->data), - flex_array_size, obj, data, 7); + flex_array_size, obj, data, 7 + unconst); err |= check_one_size_helper(SIZE_MAX, - flex_array_size, obj, data, -1); + flex_array_size, obj, data, -1 + unconst); err |= check_one_size_helper(SIZE_MAX, - flex_array_size, obj, data, SIZE_MAX - 4); + flex_array_size, obj, data, SIZE_MAX - 4 + unconst); var = 4; err |= check_one_size_helper(sizeof(*obj) + (4 * sizeof(*obj->data)), struct_size, obj, data, var++); err |= check_one_size_helper(sizeof(*obj) + (5 * sizeof(*obj->data)), struct_size, obj, data, var++); - err |= check_one_size_helper(sizeof(*obj), struct_size, obj, data, 0); + err |= check_one_size_helper(sizeof(*obj), struct_size, obj, data, 0 + unconst); err |= check_one_size_helper(sizeof(*obj) + sizeof(*obj->data), - struct_size, obj, data, 1); + struct_size, obj, data, 1 + unconst); err |= check_one_size_helper(SIZE_MAX, - struct_size, obj, data, -3); + struct_size, obj, data, -3 + unconst); err |= check_one_size_helper(SIZE_MAX, - struct_size, obj, data, SIZE_MAX - 3); + struct_size, obj, data, SIZE_MAX - 3 + unconst); pr_info("%d overflow size helper tests finished\n", count); -- cgit v1.2.3 From 92d23c6e94157739b997cacce151586a0d07bb8a Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 26 Aug 2022 09:21:16 -0700 Subject: overflow, tracing: Define the is_signed_type() macro once There are two definitions of the is_signed_type() macro: one in and a second definition in . As suggested by Linus Torvalds, move the definition of the is_signed_type() macro into the header file. Change the definition of the is_signed_type() macro to make sure that it does not trigger any sparse warnings with future versions of sparse for bitwise types. See also: https://lore.kernel.org/all/CAHk-=whjH6p+qzwUdx5SOVVHjS3WvzJQr6mDUwhEyTf6pJWzaQ@mail.gmail.com/ https://lore.kernel.org/all/CAHk-=wjQGnVfb4jehFR0XyZikdQvCZouE96xR_nnf5kqaM5qqQ@mail.gmail.com/ Cc: Andrew Morton Cc: Arnd Bergmann Cc: Dan Williams Cc: Eric Dumazet Cc: Ingo Molnar Cc: Isabella Basso Cc: "Jason A. Donenfeld" Cc: Josh Poimboeuf Cc: Luc Van Oostenryck Cc: Masami Hiramatsu Cc: Nathan Chancellor Cc: Peter Zijlstra Cc: Rasmus Villemoes Cc: Sander Vanheule Cc: Steven Rostedt Cc: Vlastimil Babka Cc: Yury Norov Signed-off-by: Bart Van Assche Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220826162116.1050972-3-bvanassche@acm.org --- include/linux/compiler.h | 6 ++++++ include/linux/overflow.h | 1 - include/linux/trace_events.h | 2 -- 3 files changed, 6 insertions(+), 3 deletions(-) (limited to 'include/linux/overflow.h') diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 01ce94b58b42..7713d7bcdaea 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -239,6 +239,12 @@ static inline void *offset_to_ptr(const int *off) /* &a[0] degrades to a pointer: a different type from an array */ #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) +/* + * Whether 'type' is a signed type or an unsigned type. Supports scalar types, + * bool and also pointer types. + */ +#define is_signed_type(type) (((type)(-1)) < (__force type)1) + /* * This is needed in functions which generate the stack canary, see * arch/x86/kernel/smpboot.c::start_secondary() for an example. diff --git a/include/linux/overflow.h b/include/linux/overflow.h index f1221d11f8e5..0eb3b192f07a 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -30,7 +30,6 @@ * https://mail-index.netbsd.org/tech-misc/2007/02/05/0000.html - * credit to Christian Biere. */ -#define is_signed_type(type) (((type)(-1)) < (type)1) #define __type_half_max(type) ((type)1 << (8*sizeof(type) - 1 - is_signed_type(type))) #define type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T))) #define type_min(T) ((T)((T)-type_max(T)-(T)1)) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index b18759a673c6..8401dec93c15 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -814,8 +814,6 @@ extern int trace_add_event_call(struct trace_event_call *call); extern int trace_remove_event_call(struct trace_event_call *call); extern int trace_event_get_offsets(struct trace_event_call *call); -#define is_signed_type(type) (((type)(-1)) < (type)1) - int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set); int trace_set_clr_event(const char *system, const char *event, int set); int trace_array_set_clr_event(struct trace_array *tr, const char *system, -- cgit v1.2.3 From d219d2a9a92e39aa92799efe8f2aa21259b6dd82 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 29 Aug 2022 13:37:17 -0700 Subject: overflow: Allow mixed type arguments When the check_[op]_overflow() helpers were introduced, all arguments were required to be the same type to make the fallback macros simpler. However, now that the fallback macros have been removed[1], it is fine to allow mixed types, which makes using the helpers much more useful, as they can be used to test for type-based overflows (e.g. adding two large ints but storing into a u8), as would be handy in the drm core[2]. Remove the restriction, and add additional self-tests that exercise some of the mixed-type overflow cases, and double-check for accidental macro side-effects. [1] https://git.kernel.org/linus/4eb6bd55cfb22ffc20652732340c4962f3ac9a91 [2] https://lore.kernel.org/lkml/20220824084514.2261614-2-gwan-gyeong.mun@intel.com Cc: Rasmus Villemoes Cc: Gwan-gyeong Mun Cc: "Gustavo A. R. Silva" Cc: Nick Desaulniers Cc: linux-hardening@vger.kernel.org Reviewed-by: Andrzej Hajda Reviewed-by: Gwan-gyeong Mun Tested-by: Gwan-gyeong Mun Signed-off-by: Kees Cook --- include/linux/overflow.h | 72 ++++++++++++++++++--------------- lib/overflow_kunit.c | 101 +++++++++++++++++++++++++++++++++-------------- 2 files changed, 113 insertions(+), 60 deletions(-) (limited to 'include/linux/overflow.h') diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 0eb3b192f07a..19dfdd74835e 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -51,40 +51,50 @@ static inline bool __must_check __must_check_overflow(bool overflow) return unlikely(overflow); } -/* - * For simplicity and code hygiene, the fallback code below insists on - * a, b and *d having the same type (similar to the min() and max() - * macros), whereas gcc's type-generic overflow checkers accept - * different types. Hence we don't just make check_add_overflow an - * alias for __builtin_add_overflow, but add type checks similar to - * below. +/** check_add_overflow() - Calculate addition with overflow checking + * + * @a: first addend + * @b: second addend + * @d: pointer to store sum + * + * Returns 0 on success. + * + * *@d holds the results of the attempted addition, but is not considered + * "safe for use" on a non-zero return value, which indicates that the + * sum has overflowed or been truncated. */ -#define check_add_overflow(a, b, d) __must_check_overflow(({ \ - typeof(a) __a = (a); \ - typeof(b) __b = (b); \ - typeof(d) __d = (d); \ - (void) (&__a == &__b); \ - (void) (&__a == __d); \ - __builtin_add_overflow(__a, __b, __d); \ -})) +#define check_add_overflow(a, b, d) \ + __must_check_overflow(__builtin_add_overflow(a, b, d)) -#define check_sub_overflow(a, b, d) __must_check_overflow(({ \ - typeof(a) __a = (a); \ - typeof(b) __b = (b); \ - typeof(d) __d = (d); \ - (void) (&__a == &__b); \ - (void) (&__a == __d); \ - __builtin_sub_overflow(__a, __b, __d); \ -})) +/** check_sub_overflow() - Calculate subtraction with overflow checking + * + * @a: minuend; value to subtract from + * @b: subtrahend; value to subtract from @a + * @d: pointer to store difference + * + * Returns 0 on success. + * + * *@d holds the results of the attempted subtraction, but is not considered + * "safe for use" on a non-zero return value, which indicates that the + * difference has underflowed or been truncated. + */ +#define check_sub_overflow(a, b, d) \ + __must_check_overflow(__builtin_sub_overflow(a, b, d)) -#define check_mul_overflow(a, b, d) __must_check_overflow(({ \ - typeof(a) __a = (a); \ - typeof(b) __b = (b); \ - typeof(d) __d = (d); \ - (void) (&__a == &__b); \ - (void) (&__a == __d); \ - __builtin_mul_overflow(__a, __b, __d); \ -})) +/** check_mul_overflow() - Calculate multiplication with overflow checking + * + * @a: first factor + * @b: second factor + * @d: pointer to store product + * + * Returns 0 on success. + * + * *@d holds the results of the attempted multiplication, but is not + * considered "safe for use" on a non-zero return value, which indicates + * that the product has overflowed or been truncated. + */ +#define check_mul_overflow(a, b, d) \ + __must_check_overflow(__builtin_mul_overflow(a, b, d)) /** check_shl_overflow() - Calculate a left-shifted value and check overflow * diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c index 7e3e43679b73..0d98c9bc75da 100644 --- a/lib/overflow_kunit.c +++ b/lib/overflow_kunit.c @@ -16,12 +16,15 @@ #include #include -#define DEFINE_TEST_ARRAY(t) \ - static const struct test_ ## t { \ - t a, b; \ - t sum, diff, prod; \ - bool s_of, d_of, p_of; \ - } t ## _tests[] +#define DEFINE_TEST_ARRAY_TYPED(t1, t2, t) \ + static const struct test_ ## t1 ## _ ## t2 ## __ ## t { \ + t1 a; \ + t2 b; \ + t sum, diff, prod; \ + bool s_of, d_of, p_of; \ + } t1 ## _ ## t2 ## __ ## t ## _tests[] + +#define DEFINE_TEST_ARRAY(t) DEFINE_TEST_ARRAY_TYPED(t, t, t) DEFINE_TEST_ARRAY(u8) = { {0, 0, 0, 0, 0, false, false, false}, @@ -222,21 +225,27 @@ DEFINE_TEST_ARRAY(s64) = { }; #endif -#define check_one_op(t, fmt, op, sym, a, b, r, of) do { \ - t _r; \ - bool _of; \ - \ - _of = check_ ## op ## _overflow(a, b, &_r); \ - KUNIT_EXPECT_EQ_MSG(test, _of, of, \ +#define check_one_op(t, fmt, op, sym, a, b, r, of) do { \ + int _a_orig = a, _a_bump = a + 1; \ + int _b_orig = b, _b_bump = b + 1; \ + bool _of; \ + t _r; \ + \ + _of = check_ ## op ## _overflow(a, b, &_r); \ + KUNIT_EXPECT_EQ_MSG(test, _of, of, \ "expected "fmt" "sym" "fmt" to%s overflow (type %s)\n", \ - a, b, of ? "" : " not", #t); \ - KUNIT_EXPECT_EQ_MSG(test, _r, r, \ + a, b, of ? "" : " not", #t); \ + KUNIT_EXPECT_EQ_MSG(test, _r, r, \ "expected "fmt" "sym" "fmt" == "fmt", got "fmt" (type %s)\n", \ - a, b, r, _r, #t); \ + a, b, r, _r, #t); \ + /* Check for internal macro side-effects. */ \ + _of = check_ ## op ## _overflow(_a_orig++, _b_orig++, &_r); \ + KUNIT_EXPECT_EQ_MSG(test, _a_orig, _a_bump, "Unexpected " #op " macro side-effect!\n"); \ + KUNIT_EXPECT_EQ_MSG(test, _b_orig, _b_bump, "Unexpected " #op " macro side-effect!\n"); \ } while (0) -#define DEFINE_TEST_FUNC(t, fmt) \ -static void do_test_ ## t(struct kunit *test, const struct test_ ## t *p) \ +#define DEFINE_TEST_FUNC_TYPED(n, t, fmt) \ +static void do_test_ ## n(struct kunit *test, const struct test_ ## n *p) \ { \ check_one_op(t, fmt, add, "+", p->a, p->b, p->sum, p->s_of); \ check_one_op(t, fmt, add, "+", p->b, p->a, p->sum, p->s_of); \ @@ -245,15 +254,18 @@ static void do_test_ ## t(struct kunit *test, const struct test_ ## t *p) \ check_one_op(t, fmt, mul, "*", p->b, p->a, p->prod, p->p_of); \ } \ \ -static void t ## _overflow_test(struct kunit *test) { \ +static void n ## _overflow_test(struct kunit *test) { \ unsigned i; \ \ - for (i = 0; i < ARRAY_SIZE(t ## _tests); ++i) \ - do_test_ ## t(test, &t ## _tests[i]); \ + for (i = 0; i < ARRAY_SIZE(n ## _tests); ++i) \ + do_test_ ## n(test, &n ## _tests[i]); \ kunit_info(test, "%zu %s arithmetic tests finished\n", \ - ARRAY_SIZE(t ## _tests), #t); \ + ARRAY_SIZE(n ## _tests), #n); \ } +#define DEFINE_TEST_FUNC(t, fmt) \ + DEFINE_TEST_FUNC_TYPED(t ## _ ## t ## __ ## t, t, fmt) + DEFINE_TEST_FUNC(u8, "%d"); DEFINE_TEST_FUNC(s8, "%d"); DEFINE_TEST_FUNC(u16, "%d"); @@ -265,6 +277,33 @@ DEFINE_TEST_FUNC(u64, "%llu"); DEFINE_TEST_FUNC(s64, "%lld"); #endif +DEFINE_TEST_ARRAY_TYPED(u32, u32, u8) = { + {0, 0, 0, 0, 0, false, false, false}, + {U8_MAX, 2, 1, U8_MAX - 2, U8_MAX - 1, true, false, true}, + {U8_MAX + 1, 0, 0, 0, 0, true, true, false}, +}; +DEFINE_TEST_FUNC_TYPED(u32_u32__u8, u8, "%d"); + +DEFINE_TEST_ARRAY_TYPED(u32, u32, int) = { + {0, 0, 0, 0, 0, false, false, false}, + {U32_MAX, 0, -1, -1, 0, true, true, false}, +}; +DEFINE_TEST_FUNC_TYPED(u32_u32__int, int, "%d"); + +DEFINE_TEST_ARRAY_TYPED(u8, u8, int) = { + {0, 0, 0, 0, 0, false, false, false}, + {U8_MAX, U8_MAX, 2 * U8_MAX, 0, U8_MAX * U8_MAX, false, false, false}, + {1, 2, 3, -1, 2, false, false, false}, +}; +DEFINE_TEST_FUNC_TYPED(u8_u8__int, int, "%d"); + +DEFINE_TEST_ARRAY_TYPED(int, int, u8) = { + {0, 0, 0, 0, 0, false, false, false}, + {1, 2, 3, U8_MAX, 2, false, true, false}, + {-1, 0, U8_MAX, U8_MAX, 0, true, true, false}, +}; +DEFINE_TEST_FUNC_TYPED(int_int__u8, u8, "%d"); + static void overflow_shift_test(struct kunit *test) { int count = 0; @@ -649,17 +688,21 @@ static void overflow_size_helpers_test(struct kunit *test) } static struct kunit_case overflow_test_cases[] = { - KUNIT_CASE(u8_overflow_test), - KUNIT_CASE(s8_overflow_test), - KUNIT_CASE(u16_overflow_test), - KUNIT_CASE(s16_overflow_test), - KUNIT_CASE(u32_overflow_test), - KUNIT_CASE(s32_overflow_test), + KUNIT_CASE(u8_u8__u8_overflow_test), + KUNIT_CASE(s8_s8__s8_overflow_test), + KUNIT_CASE(u16_u16__u16_overflow_test), + KUNIT_CASE(s16_s16__s16_overflow_test), + KUNIT_CASE(u32_u32__u32_overflow_test), + KUNIT_CASE(s32_s32__s32_overflow_test), /* Clang 13 and earlier generate unwanted libcalls on 32-bit. */ #if BITS_PER_LONG == 64 - KUNIT_CASE(u64_overflow_test), - KUNIT_CASE(s64_overflow_test), + KUNIT_CASE(u64_u64__u64_overflow_test), + KUNIT_CASE(s64_s64__s64_overflow_test), #endif + KUNIT_CASE(u32_u32__u8_overflow_test), + KUNIT_CASE(u32_u32__int_overflow_test), + KUNIT_CASE(u8_u8__int_overflow_test), + KUNIT_CASE(int_int__u8_overflow_test), KUNIT_CASE(overflow_shift_test), KUNIT_CASE(overflow_allocation_test), KUNIT_CASE(overflow_size_helpers_test), -- cgit v1.2.3 From 31970608a6d3796c3adbfbfd379fa3092de65c5d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 26 Sep 2022 12:45:32 -0700 Subject: overflow: Fix kern-doc markup for functions Fix the kern-doc markings for several of the overflow helpers and move their location into the core kernel API documentation, where it belongs (it's not driver-specific). Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Cc: linux-hardening@vger.kernel.org Reviewed-by: Akira Yokosawa Signed-off-by: Kees Cook --- Documentation/core-api/kernel-api.rst | 6 ++++++ Documentation/driver-api/basics.rst | 3 --- include/linux/overflow.h | 38 +++++++++++++++-------------------- 3 files changed, 22 insertions(+), 25 deletions(-) (limited to 'include/linux/overflow.h') diff --git a/Documentation/core-api/kernel-api.rst b/Documentation/core-api/kernel-api.rst index 0793c400d4b0..06f4ab122697 100644 --- a/Documentation/core-api/kernel-api.rst +++ b/Documentation/core-api/kernel-api.rst @@ -118,6 +118,12 @@ Text Searching CRC and Math Functions in Linux =============================== +Arithmetic Overflow Checking +---------------------------- + +.. kernel-doc:: include/linux/overflow.h + :internal: + CRC Functions ------------- diff --git a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst index 3e2dae954898..4b4d8e28d3be 100644 --- a/Documentation/driver-api/basics.rst +++ b/Documentation/driver-api/basics.rst @@ -107,9 +107,6 @@ Kernel utility functions .. kernel-doc:: kernel/panic.c :export: -.. kernel-doc:: include/linux/overflow.h - :internal: - Device Resource Management -------------------------- diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 19dfdd74835e..1d3be1a2204c 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -51,8 +51,8 @@ static inline bool __must_check __must_check_overflow(bool overflow) return unlikely(overflow); } -/** check_add_overflow() - Calculate addition with overflow checking - * +/** + * check_add_overflow() - Calculate addition with overflow checking * @a: first addend * @b: second addend * @d: pointer to store sum @@ -66,8 +66,8 @@ static inline bool __must_check __must_check_overflow(bool overflow) #define check_add_overflow(a, b, d) \ __must_check_overflow(__builtin_add_overflow(a, b, d)) -/** check_sub_overflow() - Calculate subtraction with overflow checking - * +/** + * check_sub_overflow() - Calculate subtraction with overflow checking * @a: minuend; value to subtract from * @b: subtrahend; value to subtract from @a * @d: pointer to store difference @@ -81,8 +81,8 @@ static inline bool __must_check __must_check_overflow(bool overflow) #define check_sub_overflow(a, b, d) \ __must_check_overflow(__builtin_sub_overflow(a, b, d)) -/** check_mul_overflow() - Calculate multiplication with overflow checking - * +/** + * check_mul_overflow() - Calculate multiplication with overflow checking * @a: first factor * @b: second factor * @d: pointer to store product @@ -96,23 +96,24 @@ static inline bool __must_check __must_check_overflow(bool overflow) #define check_mul_overflow(a, b, d) \ __must_check_overflow(__builtin_mul_overflow(a, b, d)) -/** check_shl_overflow() - Calculate a left-shifted value and check overflow - * +/** + * check_shl_overflow() - Calculate a left-shifted value and check overflow * @a: Value to be shifted * @s: How many bits left to shift * @d: Pointer to where to store the result * * Computes *@d = (@a << @s) * - * Returns true if '*d' cannot hold the result or when 'a << s' doesn't + * Returns true if '*@d' cannot hold the result or when '@a << @s' doesn't * make sense. Example conditions: - * - 'a << s' causes bits to be lost when stored in *d. - * - 's' is garbage (e.g. negative) or so large that the result of - * 'a << s' is guaranteed to be 0. - * - 'a' is negative. - * - 'a << s' sets the sign bit, if any, in '*d'. * - * '*d' will hold the results of the attempted shift, but is not + * - '@a << @s' causes bits to be lost when stored in *@d. + * - '@s' is garbage (e.g. negative) or so large that the result of + * '@a << @s' is guaranteed to be 0. + * - '@a' is negative. + * - '@a << @s' sets the sign bit, if any, in '*@d'. + * + * '*@d' will hold the results of the attempted shift, but is not * considered "safe for use" if true is returned. */ #define check_shl_overflow(a, s, d) __must_check_overflow(({ \ @@ -129,7 +130,6 @@ static inline bool __must_check __must_check_overflow(bool overflow) /** * size_mul() - Calculate size_t multiplication with saturation at SIZE_MAX - * * @factor1: first factor * @factor2: second factor * @@ -149,7 +149,6 @@ static inline size_t __must_check size_mul(size_t factor1, size_t factor2) /** * size_add() - Calculate size_t addition with saturation at SIZE_MAX - * * @addend1: first addend * @addend2: second addend * @@ -169,7 +168,6 @@ static inline size_t __must_check size_add(size_t addend1, size_t addend2) /** * size_sub() - Calculate size_t subtraction with saturation at SIZE_MAX - * * @minuend: value to subtract from * @subtrahend: value to subtract from @minuend * @@ -192,7 +190,6 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) /** * array_size() - Calculate size of 2-dimensional array. - * * @a: dimension one * @b: dimension two * @@ -205,7 +202,6 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) /** * array3_size() - Calculate size of 3-dimensional array. - * * @a: dimension one * @b: dimension two * @c: dimension three @@ -220,7 +216,6 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) /** * flex_array_size() - Calculate size of a flexible array member * within an enclosing structure. - * * @p: Pointer to the structure. * @member: Name of the flexible array member. * @count: Number of elements in the array. @@ -237,7 +232,6 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) /** * struct_size() - Calculate size of structure with trailing flexible array. - * * @p: Pointer to the structure. * @member: Name of the array member. * @count: Number of elements in the array. -- cgit v1.2.3