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authorKees Cook <keescook@chromium.org>2021-05-12 21:51:10 -0700
committerKees Cook <keescook@chromium.org>2021-09-25 08:20:49 -0700
commita52f8a59aef46b59753e583bf4b28fccb069ce64 (patch)
tree2cd6a83cc7f41e74ed046f927e3944dae5a37e1f /security
parentc430f60036af44079170ff71a461b9d7cf5ee431 (diff)
fortify: Explicitly disable Clang support
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
Diffstat (limited to 'security')
-rw-r--r--security/Kconfig3
1 files changed, 3 insertions, 0 deletions
diff --git a/security/Kconfig b/security/Kconfig
index 0ced7fd33e4d..fe6c0395fa02 100644
--- 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.