From: Kees Cook keescook@chromium.org
commit f87b1c49bc675da30d8e1e8f4b60b800312c7b90 upstream.
When the uaccess .fixup section was renamed to .text.fixup, one case was missed. Under ld.bfd, the orphaned section was moved close to .text (since they share the "ax" bits), so things would work normally on uaccess faults. Under ld.lld, the orphaned section was placed outside the .text section, making it unreachable.
Link: https://github.com/ClangBuiltLinux/linux/issues/282 Link: https://bugs.chromium.org/p/chromium/issues/detail?id=1020633#c44 Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.1912032147340.17114@knanqh.ubzr Link: https://lore.kernel.org/lkml/202002071754.F5F073F1D@keescook/
Fixes: c4a84ae39b4a5 ("ARM: 8322/1: keep .text and .fixup regions closer together") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook keescook@chromium.org Reviewed-by: Ard Biesheuvel ardb@kernel.org Reviewed-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Russell King rmk+kernel@armlinux.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm/lib/copy_from_user.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm/lib/copy_from_user.S +++ b/arch/arm/lib/copy_from_user.S @@ -100,7 +100,7 @@ ENTRY(arm_copy_from_user)
ENDPROC(arm_copy_from_user)
- .pushsection .fixup,"ax" + .pushsection .text.fixup,"ax" .align 0 copy_abort_preamble ldmfd sp!, {r1, r2}