Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.15 11/20] fortify: Explicitly disable Clang support | Date | Fri, 19 Nov 2021 18:39:29 +0100 |
| |
From: Kees Cook <keescook@chromium.org>
commit a52f8a59aef46b59753e583bf4b28fccb069ce64 upstream.
Clang has never correctly compiled the FORTIFY_SOURCE defenses due to a couple bugs:
Eliding inlines with matching __builtin_* names https://bugs.llvm.org/show_bug.cgi?id=50322
Incorrect __builtin_constant_p() of some globals https://bugs.llvm.org/show_bug.cgi?id=41459
In the process of making improvements to the FORTIFY_SOURCE defenses, the first (silent) bug (coincidentally) becomes worked around, but exposes the latter which breaks the build. As such, Clang must not be used with CONFIG_FORTIFY_SOURCE until at least latter bug is fixed (in Clang 13), and the fortify routines have been rearranged.
Update the Kconfig to reflect the reality of the current situation.
Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/lkml/CAKwvOd=A+ueGV2ihdy5GtgR2fQbcXjjAtVxv3=cPjffpebZB7A@mail.gmail.com Cc: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- security/Kconfig | 3 +++ 1 file changed, 3 insertions(+)
--- a/security/Kconfig +++ b/security/Kconfig @@ -191,6 +191,9 @@ config HARDENED_USERCOPY_PAGESPAN config FORTIFY_SOURCE bool "Harden common str/mem functions against buffer overflows" depends on ARCH_HAS_FORTIFY_SOURCE + # https://bugs.llvm.org/show_bug.cgi?id=50322 + # https://bugs.llvm.org/show_bug.cgi?id=41459 + depends on !CC_IS_CLANG help Detect overflows of buffers in common string and memory functions where the compiler can determine and validate the buffer sizes.
| |