https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106625
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Tim Lange <tla...@gcc.gnu.org>: https://gcc.gnu.org/g:7a6564c9b277d9f93582605758d57457de696deb commit r13-2546-g7a6564c9b277d9f93582605758d57457de696deb Author: Tim Lange <m...@tim-lange.me> Date: Wed Sep 7 17:41:28 2022 +0200 analyzer: support for symbolic values in the out-of-bounds checker [PR106625] This patch adds support for reasoning about the inequality of two symbolic values in the special case specifically suited for reasoning about out-of-bounds past the end of the buffer. With this patch, the analyzer catches off-by-one errors and more even when the offset and capacity is symbolic. Regrtested on Linux x86_64 and tested on coreutils, curl, httpd and openssh as usual. 2022-09-07 Tim Lange <m...@tim-lange.me> gcc/analyzer/ChangeLog: PR analyzer/106625 * analyzer.h (region_offset): Eliminate m_is_symbolic member. * region-model-impl-calls.cc (region_model::impl_call_realloc): Refine implementation to be more precise. * region-model.cc (class symbolic_past_the_end): Abstract diagnostic class to complain about accesses past the end with symbolic values. (class symbolic_buffer_overflow): Concrete diagnostic class to complain about buffer overflows with symbolic values. (class symbolic_buffer_overread): Concrete diagnostic class to complain about buffer overreads with symbolic values. (region_model::check_symbolic_bounds): New function. (maybe_get_integer_cst_tree): New helper function. (region_model::check_region_bounds): Add call to check_symbolic_bounds if offset is not concrete. (region_model::eval_condition_without_cm): Add support for EQ_EXPR and GT_EXPR with binaryop_svalues. (is_positive_svalue): New hleper function. (region_model::symbolic_greater_than): New function to handle GT_EXPR comparisons with symbolic values. (region_model::structural_equality): New function to compare whether two svalues are structured the same, i.e. evaluate to the same value. (test_struct): Reflect changes to region::calc_offset. (test_var): Likewise. (test_array_2): Likewise and add selftest with symbolic i. * region-model.h (class region_model): Add check_symbolic_bounds, symbolic_greater_than and structural_equality. * region.cc (region::get_offset): Reflect changes to region::calc_offset. (region::calc_offset): Compute the symbolic offset if the offset is not concrete. (region::get_relative_symbolic_offset): New function to return the symbolic offset in bytes relative to its parent. (field_region::get_relative_symbolic_offset): Likewise. (element_region::get_relative_symbolic_offset): Likewise. (offset_region::get_relative_symbolic_offset): Likewise. (bit_range_region::get_relative_symbolic_offset): Likewise. * region.h: Add get_relative_symbolic_offset. * store.cc (binding_key::make): Reflect changes to region::calc_offset. (binding_map::apply_ctor_val_to_range): Likewise. (binding_map::apply_ctor_pair_to_child_region): Likewise. (binding_cluster::bind_compound_sval): Likewise. (binding_cluster::get_any_binding): Likewise. (binding_cluster::maybe_get_compound_binding): Likewise. gcc/ChangeLog: PR analyzer/106625 * doc/invoke.texi: State that the checker also reasons about symbolic values. gcc/testsuite/ChangeLog: PR analyzer/106625 * gcc.dg/analyzer/data-model-1.c: Change expected result. * gcc.dg/analyzer/out-of-bounds-5.c: New test. * gcc.dg/analyzer/out-of-bounds-realloc-grow.c: New test. * gcc.dg/analyzer/symbolic-gt-1.c: New test.
