On Mar 13, 2024, at 15:19, Qing Zhao wrote: On Mar 11, 2024, at 13:15, Siddhesh Poyarekar wrote: On 2024-02-16 14:47, Qing Zhao wrote: gcc/c-family/ChangeLog: * c-ubsan.cc (get_bound_from_access_with_size): New function. (ubsan_instrument_bounds): Handle call to .ACCESS_WITH_SIZE. gcc/testsuite/ChangeLog: * gcc.dg/ubsan/flex-array-counted-by-bounds-2.c: New test. * gcc.dg/ubsan/flex-array-counted-by-bounds-3.c: New test. * gcc.dg/ubsan/flex-array-counted-by-bounds.c: New test. --- gcc/c-family/c-ubsan.cc | 42 +++++++++++++++++ .../ubsan/flex-array-counted-by-bounds-2.c | 45 ++++++++++++++++++ .../ubsan/flex-array-counted-by-bounds-3.c | 34 ++++++++++++++ .../ubsan/flex-array-counted-by-bounds.c | 46 +++++++++++++++++++ 4 files changed, 167 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds-2.c create mode 100644 gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds-3.c create mode 100644 gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds.c diff --git a/gcc/c-family/c-ubsan.cc b/gcc/c-family/c-ubsan.cc index 940982819ddf..164b29845b3a 100644 --- a/gcc/c-family/c-ubsan.cc +++ b/gcc/c-family/c-ubsan.cc @@ -376,6 +376,40 @@ ubsan_instrument_return (location_t loc) return build_call_expr_loc (loc, t, 1, build_fold_addr_expr_loc (loc, data)); } +/* Get the tree that represented the number of counted_by, i.e, the maximum + number of the elements of the object that the call to .ACCESS_WITH_SIZE + points to, this number will be the bound of the corresponding array. */ +static tree +get_bound_from_access_with_size (tree call) +{ + if (!is_access_with_size_p (call)) + return NULL_TREE; + + tree ref_to_size = CALL_EXPR_ARG (call, 1); + unsigned int type_of_size = TREE_INT_CST_LOW (CALL_EXPR_ARG (call, 2)); Again for consistency, this should probably be class_of_size. Okay, I will update this consistently with the change relate to the 3rd argument. + tree type = TREE_TYPE (CALL_EXPR_ARG (call, 3)); + tree size = fold_build2 (MEM_REF, type, unshare_expr (ref_to_size), + build_int_cst (ptr_type_node, 0)); + /* If size is negative value, treat it as zero. */ + if (!TYPE_UNSIGNED (type)) + { + tree cond = fold_build2 (LT_EXPR, boolean_type_node, + unshare_expr (size), build_zero_cst (type)); + size = fold_build3 (COND_EXPR, type, cond, + build_zero_cst (type), size); + } + + /* Only when type_of_size is 1,i.e, the number of the elements of + the object type, return the size. */ + if (type_of_size != 1) + return NULL_TREE; + else + size = fold_convert (sizetype, size); + + return size; +} + + /* Instrument array bounds for ARRAY_REFs. We create special builtin, that gets expanded in the sanopt pass, and make an array dimension of it. ARRAY is the array, *INDEX is an index to the array. @@ -401,6 +435,14 @@ ubsan_instrument_bounds (location_t loc, tree array, tree *index, && COMPLETE_TYPE_P (type) && integer_zerop (TYPE_SIZE (type))) bound = build_int_cst (TREE_TYPE (TYPE_MIN_VALUE (domain)), -1); + else if (INDIRECT_REF_P (array) + && is_access_with_size_p ((TREE_OPERAND (array, 0)))) + { + bound = get_bound_from_access_with_size ((TREE_OPERAND (array, 0))); + bound = fold_build2 (MINUS_EXPR, TREE_TYPE (bound), + bound, + build_int_cst (TREE_TYPE (bound), 1)); + } This will wrap if bound == 0, maybe that needs to be special-cased. And maybe also add a test for it below. Will check on this to see whether a new testing is needed. Checked, the current code can handle the case when bound==0 correctly. I just add a new testing case for this. thanks. Qing Thanks a lot for the review. Qing else return NULL_TREE; } diff --git a/gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds-2.c b/gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds-2.c new file mode 100644 index 000000000000..148934975ee5 --- /dev/null +++ b/gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds-2.c @@ -0,0 +1,45 @@ +/* test the attribute counted_by and its usage in + bounds sanitizer combined with VLA. */ +/* { dg-do run } */ +/* { dg-options "-fsanitize=bounds" } */ +/* { dg-output "index 11 out of bounds for type 'int \\\[\\\*\\\]\\\[\\\*\\\]'\[^\n\r]*(\n|\r\n|\r)" } */ +/* { dg-output "\[^\n\r]*index 20 out of bounds for type 'int \\\[\\\*\\\]\\\[\\\*\\\]\\\[\\\*\\\]'\[^\n\r]*(\n|\r\n|\r)" } */ +/* { dg-output "\[^\n\r]*index 11 out of bounds for type 'int \\\[\\\*\\\]\\\[\\\*\\\]'\[^\n\r]*(\n|\r\n|\r)" } */ +/* { dg-output "\[^\n\r]*index 10 out of bounds for type 'int \\\[\\\*\\\]'\[^\n\r]*(\n|\r\n|\r)" } */ + + +#include + +void __attribute__((__noinline__)) setup_and_test_vla (int n, int m) +{ + struct foo { + int n; + int p[][n] __attribute__((counted_by(n))); + } *f; + + f = (struct foo *) malloc (sizeof(struct foo) + m*sizeof(int[n])); + f->n = m; + f->p[m][n-1]=1; + return; +} + +void __attribute__((__noinline__)) setup_and_test_vla_1 (int n1, int n2, int m) +{ + struct foo { + int n; + int p[][n2][n1] __attribute__((counted_by(n))); + } *f; + + f = (struct foo *) malloc (sizeof(struct foo) + m*sizeof(int[n2][n1])); + f->n = m; + f->p[m][n2][n1]=1; + return; +} + +int main(int argc, char *argv[]) +{ + setup_and_test_vla (10, 11); + setup_and_test_vla_1 (10, 11, 20); + return 0; +} + diff --git a/gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds-3.c b/gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds-3.c new file mode 100644 index 000000000000..33bdea1c430b --- /dev/null +++ b/gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds-3.c @@ -0,0 +1,34 @@ +/* test the attribute counted_by and its usage in bounds + sanitizer. when counted_by field is negative value. */ +/* { dg-do run } */ +/* { dg-options "-fsanitize=bounds" } */ + +#include + +struct annotated { + int b; + int c[] __attribute__ ((counted_by (b))); +} *array_annotated; + +void __attribute__((__noinline__)) setup (int annotated_count) +{ + array_annotated + = (struct annotated *)malloc (sizeof (struct annotated)); + array_annotated->b = annotated_count; + + return; +} + +void __attribute__((__noinline__)) test (int annotated_index) +{ + array_annotated->c[annotated_index] = 2; +} + +int main(int argc, char *argv[]) +{ + setup (-3); + test (2); + return 0; +} + +/* { dg-output "24:21: runtime error: index 2 out of bounds for type" } */ diff --git a/gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds.c b/gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds.c new file mode 100644 index 000000000000..81eaeb3f2681 --- /dev/null +++ b/gcc/testsuite/gcc.dg/ubsan/flex-array-counted-by-bounds.c @@ -0,0 +1,46 @@ +/* test the attribute counted_by and its usage in + bounds sanitizer. */ +/* { dg-do run } */ +/* { dg-options "-fsanitize=bounds" } */ + +#include + +struct flex { + int b; + int c[]; +} *array_flex; + +struct annotated { + int b; + int c[] __attribute__ ((counted_by (b))); +} *array_annotated; + +void __attribute__((__noinline__)) setup (int normal_count, int annotated_count) +{ + array_flex + = (struct flex *)malloc (sizeof (struct flex) + + normal_count * sizeof (int)); + array_flex->b = normal_count; + + array_annotated + = (struct annotated *)malloc (sizeof (struct annotated) + + annotated_count * sizeof (int)); + array_annotated->b = annotated_count; + + return; +} + +void __attribute__((__noinline__)) test (int normal_index, int annotated_index) +{ + array_flex->c[normal_index] = 1; + array_annotated->c[annotated_index] = 2; +} + +int main(int argc, char *argv[]) +{ + setup (10, 10); + test (10, 10); + return 0; +} + +/* { dg-output "36:21: runtime error: index 10 out of bounds for type" } */