diff options
| author | Kees Cook <keescook@chromium.org> | 2022-02-10 01:40:41 +0100 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2022-02-16 23:30:37 +0100 |
| commit | 230f6fa2c1db6a3f3e668cfe95995ac8e6eee212 (patch) | |
| tree | 0efbee5d1df73b95483adf495bb6e2232342fc7d /lib | |
| parent | overflow: Implement size_t saturating arithmetic helpers (diff) | |
| download | linux-230f6fa2c1db6a3f3e668cfe95995ac8e6eee212.tar.xz linux-230f6fa2c1db6a3f3e668cfe95995ac8e6eee212.zip | |
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 <gustavoars@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Tested-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/lkml/20220210010407.GA701603@embeddedor
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/test_overflow.c | 26 |
1 files changed, 17 insertions, 9 deletions
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); |