[Bug target/96191] aarch64 stack_protect_test canary leak

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96191

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Richard Sandiford
<rsandifo@gcc.gnu.org>:

https://gcc.gnu.org/g:3e40be9cc92d3fa117be7f4fab07cedeed8361a2

commit r9-8795-g3e40be9cc92d3fa117be7f4fab07cedeed8361a2
Author: Richard Sandiford <richard.sandiford@arm.com>
Date:   Fri Aug 7 12:17:37 2020 +0100

    arm: Clear canary value after stack_protect_test [PR96191]

    The stack_protect_test patterns were leaving the canary value in the
    temporary register, meaning that it was often still in registers on
    return from the function.  An attacker might therefore have been
    able to use it to defeat stack-smash protection for a later function.

    gcc/
            PR target/96191
            * config/arm/arm.md (arm_stack_protect_test_insn): Zero out
            operand 2 after use.
            * config/arm/thumb1.md (thumb1_stack_protect_test_insn): Likewise.

    gcc/testsuite/
            * gcc.target/arm/stack-protector-1.c: New test.
            * gcc.target/arm/stack-protector-2.c: Likewise.

    (cherry picked from commit 6a3f3e08723063ea2dadb7ddf503f02972a724e2)