The tests for initializing a variable defined between a switch
statement's test and its first "case" statement are currently not
initialized in Clang[1] nor the proposed auto-initialization feature in
GCC.
We should retain the test (so that we can evaluate compiler fixes),
but mark it as an "expected fail". The rest of the kernel source will
be adjusted to avoid this corner case.
Also disable -Wswitch-unreachable for the test so that the intentionally
broken code won't trigger warnings for GCC (nor future Clang) when
initialization happens this unhandled place.
[1] https://bugs.llvm.org/show_bug.cgi?id=44916
Suggested-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
[adelva: cherry picking to avoid boot test flakes]
Bug: 144999193
Link: https://lore.kernel.org/lkml/202002191358.2897A07C6@keescook/
Change-Id: I0e691f2299ab42526ea306a92551a1188c469136
Signed-off-by: Alistair Delva <adelva@google.com>
Upstream commit 8c30d32b1a ("lib/test_stackinit: Handle Clang
auto-initialization pattern").
While the gcc plugin for automatic stack variable initialization (i.e.
CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL) performs initialization with
0x00 bytes, the Clang automatic stack variable initialization (i.e.
CONFIG_INIT_STACK_ALL) uses various type-specific patterns that are
typically 0xAA. Therefore the stackinit selftest has been fixed to check
that bytes are no longer the test fill pattern of 0xFF (instead of looking
for bytes that have become 0x00). This retains the test coverage for the
0x00 pattern of the gcc plugin while adding coverage for the mostly 0xAA
pattern of Clang.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Bug: 144999193
Change-Id: Ieb59dd5ba351d9ae96e5e3ad22f686be4524281a
Signed-off-by: Alexander Potapenko <glider@google.com>
Kees Cook