[Bug middle-end/78149] missing warning on strncpy buffer overflow due to an excessive bound

["msebor at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78149

--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
Author: msebor
Date: Thu Dec  8 00:01:33 2016
New Revision: 243419

URL: https://gcc.gnu.org/viewcvs?rev=243419&root=gcc&view=rev
Log:
PR c/53562 - Add -Werror= support for -D_FORTIFY_SOURCE /
__builtin___memcpy_chk
PR middle-end/77784 - duplicate warning for snprintf when n > object size
PR middle-end/78149 - missing warning on strncpy buffer overflow due to an
excessive bound
PR middle-end/78138 - missing warnings on buffer overflow with non-constant
source length

gcc/c-family/ChangeLog:

        PR c/53562
        PR middle-end/77784
        PR middle-end/78149
        PR middle-end/78138
        * c.opt (-Wstringop-overflow): New option.

gcc/ChangeLog:

        PR middle-end/77784
        PR middle-end/78149
        PR middle-end/78138

        * builtins.c (expand_builtin_strcat, expand_builtin_strncat): New
        functions.
        (compute_dest_size, get_size_range, check_sizes, check_strncat_sizes)
        (check_memop_sizes): Same.
        (expand_builtin_memcpy): Call check memop_sizes.
        (expand_builtin_mempcpy): Same.
        (expand_builtin_memset): Same,
        (expand_builtin_bzero): Same.
        (expand_builtin_memory_chk): Call check_sizes.
        (expand_builtin_strcpy): Same.
        (expand_builtin_strncpy): Same.
        (maybe_emit_sprintf_chk_warning): Same.
        (expand_builtin): Handle strcat and strncat.
        (fini_object_sizes): Reset pointers.
        (compute_object_size): New function.
        * gimple-ssa-sprintf.c (pass_sprintf_length::handle_gimple_call):
        Avoid issuing warnings also issued during built-in expansion.
        * doc/invoke.texi (Warning Options): Document -Wstringop-overflow.

gcc/testsuite/ChangeLog:

        PR middle-end/77784
        PR middle-end/78149
        PR middle-end/78138

        * c-c++-common/Wsizeof-pointer-memaccess2.c: Adjust expected
diagnostic.
        * g++.dg/ext/builtin-object-size3.C (bar): Same.
        * g++.dg/ext/strncpy-chk1.C: Same.
        * g++.dg/opt/memcpy1.C: Same.
        * g++.dg/torture/Wsizeof-pointer-memaccess1.C: Same.
        * gcc.c-torture/compile/pr55569.c: Disable -Wstringop-overflow.
        * gcc.dg/Wobjsize-1.c: Adjust expected diagnostic.
        * gcc.dg/attr-alloc_size.c: Same.
        * gcc.dg/builtin-stringop-chk-1.c: Adjust expected diagnostic.
        * gcc.dg/builtin-stringop-chk-2.c: Same.
        * gcc.dg/builtin-stringop-chk-4.c: New test.
        * gcc.dg/builtin-strncat-chk-1.c: Adjust expected diagnostic.
        * gcc.dg/memcpy-2.c: Same.
        * gcc.dg/pr40340-1.c: Same.
        * gcc.dg/pr40340-2.c (main): Same.
        * gcc.dg/pr40340-5.c (main): Same.
        * gcc.dg/torture/Wsizeof-pointer-memaccess1.c: Same.
        * gcc.dg/torture/pr71132.c: Disable -Wstringop-overflow.
        * gcc.dg/tree-ssa/builtin-sprintf-warn-1.c: Adjust text of expected
        warning.
        * gfortran.dg/char_length_3.f90: Prune expected warnings.
        * gfortran.dg/pr38868.f: Add expected warnings.


Added:
    trunk/gcc/testsuite/gcc.dg/builtin-stringop-chk-4.c
    trunk/gcc/testsuite/gcc.dg/builtin-stringop-chk-5.c
    trunk/gcc/testsuite/gcc.dg/builtin-stringop-chk-6.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/builtins.c
    trunk/gcc/c-family/ChangeLog
    trunk/gcc/c-family/c.opt
    trunk/gcc/doc/invoke.texi
    trunk/gcc/gimple-ssa-sprintf.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/c-c++-common/Wsizeof-pointer-memaccess2.c
    trunk/gcc/testsuite/g++.dg/ext/builtin-object-size3.C
    trunk/gcc/testsuite/g++.dg/ext/strncpy-chk1.C
    trunk/gcc/testsuite/g++.dg/opt/memcpy1.C
    trunk/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess1.C
    trunk/gcc/testsuite/g++.dg/torture/Wsizeof-pointer-memaccess2.C
    trunk/gcc/testsuite/gcc.c-torture/compile/pr55569.c
    trunk/gcc/testsuite/gcc.dg/Wobjsize-1.c
    trunk/gcc/testsuite/gcc.dg/attr-alloc_size.c
    trunk/gcc/testsuite/gcc.dg/builtin-stringop-chk-1.c
    trunk/gcc/testsuite/gcc.dg/builtin-stringop-chk-2.c
    trunk/gcc/testsuite/gcc.dg/builtin-strncat-chk-1.c
    trunk/gcc/testsuite/gcc.dg/fstack-protector-strong.c
    trunk/gcc/testsuite/gcc.dg/memcpy-2.c
    trunk/gcc/testsuite/gcc.dg/pr40340-1.c
    trunk/gcc/testsuite/gcc.dg/pr40340-2.c
    trunk/gcc/testsuite/gcc.dg/pr40340-5.c
    trunk/gcc/testsuite/gcc.dg/torture/Wsizeof-pointer-memaccess1.c
    trunk/gcc/testsuite/gcc.dg/torture/pr71132.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-1.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-3.c
    trunk/gcc/testsuite/gfortran.dg/char_length_3.f90
    trunk/gcc/testsuite/gfortran.dg/pr38868.f