From: Szabolcs Nagy <Szabolcs.Nagy@arm.com>
To: Mark Brown <broonie@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
Andrew Morton <akpm@linux-foundation.org>,
Marc Zyngier <maz@kernel.org>,
Oliver Upton <oliver.upton@linux.dev>,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Arnd Bergmann <arnd@arndb.de>, Oleg Nesterov <oleg@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
Kees Cook <keescook@chromium.org>, Shuah Khan <shuah@kernel.org>,
"Rick P. Edgecombe" <rick.p.edgecombe@intel.com>,
Deepak Gupta <debug@rivosinc.com>,
Ard Biesheuvel <ardb@kernel.org>
Cc: "H.J. Lu" <hjl.tools@gmail.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org
Subject: Re: [PATCH 22/35] arm64/mm: Implement map_shadow_stack()
Date: Tue, 18 Jul 2023 10:10:04 +0100 [thread overview]
Message-ID: <ZLZW7Kvg2Rep8ySO@arm.com> (raw)
In-Reply-To: <20230716-arm64-gcs-v1-22-bf567f93bba6@kernel.org>
The 07/16/2023 22:51, Mark Brown wrote:
> +SYSCALL_DEFINE3(map_shadow_stack, unsigned long, addr, unsigned long, size, unsigned int, flags)
> +{
> + unsigned long aligned_size;
> + unsigned long __user *cap_ptr;
> + unsigned long cap_val;
> + int ret;
> +
> + if (!system_supports_gcs())
> + return -EOPNOTSUPP;
> +
> + if (flags)
> + return -EINVAL;
> +
> + /*
> + * An overflow would result in attempting to write the restore token
> + * to the wrong location. Not catastrophic, but just return the right
> + * error code and block it.
> + */
> + aligned_size = PAGE_ALIGN(size);
> + if (aligned_size < size)
> + return -EOVERFLOW;
> +
> + addr = alloc_gcs(addr, aligned_size, 0, false);
> + if (IS_ERR_VALUE(addr))
> + return addr;
> +
> + /*
> + * Put a cap token at the end of the allocated region so it
> + * can be switched to.
> + */
> + cap_ptr = (unsigned long __user *)(addr + aligned_size -
> + (2 * sizeof(unsigned long)));
> + cap_val = GCS_CAP(cap_ptr);
> +
> + ret = copy_to_user_gcs(cap_ptr, &cap_val, 1);
with
uint64_t *p = map_shadow_stack(0, N*8, 0);
i'd expect p[N-1] to be the end token and p[N-2] to be the cap token,
not p[PAGE_ALIGN(N*8)/8-2].
if we allow misalligned size here (and in munmap) then i think it's
better to not page align. size%8!=0 || size<16 can be an error.
> + if (ret != 0) {
> + vm_munmap(addr, size);
> + return -EFAULT;
> + }
> +
> + return addr;
> +}
next prev parent reply other threads:[~2023-07-18 9:11 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-16 21:50 [PATCH 00/35] arm64/gcs: Provide support for GCS at EL0 Mark Brown
2023-07-16 21:50 ` [PATCH 01/35] prctl: arch-agnostic prctl for shadow stack Mark Brown
2023-07-18 17:45 ` Edgecombe, Rick P
2023-07-18 18:54 ` Mark Brown
2023-07-16 21:50 ` [PATCH 02/35] prctl: Add flag for shadow stack writeability and push/pop Mark Brown
2023-07-18 17:47 ` Edgecombe, Rick P
2023-07-18 19:10 ` Mark Brown
2023-07-16 21:50 ` [PATCH 03/35] arm64: Document boot requirements for Guarded Control Stacks Mark Brown
2023-07-16 21:51 ` [PATCH 04/35] arm64/gcs: Document the ABI " Mark Brown
2023-07-17 11:42 ` Jonathan Cameron
2023-07-19 11:44 ` Mike Rapoport
2023-07-19 13:25 ` Mark Brown
2023-07-19 14:04 ` Mike Rapoport
2023-07-16 21:51 ` [PATCH 05/35] arm64/sysreg: Add new system registers for GCS Mark Brown
2023-07-16 21:51 ` [PATCH 06/35] arm64/sysreg: Add definitions for architected GCS caps Mark Brown
2023-07-16 21:51 ` [PATCH 07/35] arm64/gcs: Add manual encodings of GCS instructions Mark Brown
2023-07-16 21:51 ` [PATCH 08/35] arm64/gcs: Provide copy_to_user_gcs() Mark Brown
2023-07-16 21:51 ` [PATCH 09/35] arm64/cpufeature: Runtime detection of Guarded Control Stack (GCS) Mark Brown
2023-07-16 21:51 ` [PATCH 10/35] arm64/mm: Allocate PIE slots for EL0 guarded control stack Mark Brown
2023-07-16 21:51 ` [PATCH 11/35] mm: Define VM_SHADOW_STACK for arm64 when we support GCS Mark Brown
2023-07-16 21:51 ` [PATCH 12/35] arm64/mm: Map pages for guarded control stack Mark Brown
2023-07-16 21:51 ` [PATCH 13/35] KVM: arm64: Manage GCS registers for guests Mark Brown
2023-07-16 21:51 ` [PATCH 14/35] arm64: Disable traps for GCS usage at EL0 and EL1 Mark Brown
2023-07-16 21:51 ` [PATCH 15/35] arm64/idreg: Add overrride for GCS Mark Brown
2023-07-16 21:51 ` [PATCH 16/35] arm64/hwcap: Add hwcap " Mark Brown
2023-07-16 21:51 ` [PATCH 17/35] arm64/traps: Handle GCS exceptions Mark Brown
2023-07-17 12:12 ` Jonathan Cameron
2023-07-16 21:51 ` [PATCH 18/35] arm64/mm: Handle GCS data aborts Mark Brown
2023-07-16 21:51 ` [PATCH 19/35] arm64/gcs: Context switch GCS registers for EL0 Mark Brown
2023-07-16 21:51 ` [PATCH 20/35] arm64/gcs: Allocate a new GCS for threads with GCS enabled Mark Brown
2023-07-16 21:51 ` [PATCH 21/35] arm64/gcs: Implement shadow stack prctl() interface Mark Brown
2023-07-18 17:51 ` Edgecombe, Rick P
2023-07-18 19:37 ` Mark Brown
2023-07-16 21:51 ` [PATCH 22/35] arm64/mm: Implement map_shadow_stack() Mark Brown
2023-07-18 9:10 ` Szabolcs Nagy [this message]
2023-07-18 13:55 ` Mark Brown
2023-07-18 15:49 ` Edgecombe, Rick P
2023-07-16 21:51 ` [PATCH 23/35] arm64/signal: Set up and restore the GCS context for signal handlers Mark Brown
2023-07-16 21:51 ` [PATCH 24/35] arm64/signal: Expose GCS state in signal frames Mark Brown
2023-07-16 21:51 ` [PATCH 25/35] arm64/ptrace: Expose GCS via ptrace and core files Mark Brown
2023-07-16 21:51 ` [PATCH 26/35] arm64: Add Kconfig for Guarded Control Stack (GCS) Mark Brown
2023-07-17 12:32 ` Jonathan Cameron
2023-07-16 21:51 ` [PATCH 27/35] kselftest/arm64: Verify the GCS hwcap Mark Brown
2023-07-16 21:51 ` [PATCH 28/35] kselftest/arm64: Add GCS as a detected feature in the signal tests Mark Brown
2023-07-16 21:51 ` [PATCH 29/35] kselftest/arm64: Add framework support for GCS to signal handling tests Mark Brown
2023-07-16 21:51 ` [PATCH 30/35] kselftest/arm64: Allow signals tests to specify an expected si_code Mark Brown
2023-07-16 21:51 ` [PATCH 31/35] kselftest/arm64: Always run signals tests with GCS enabled Mark Brown
2023-07-16 21:51 ` [PATCH 32/35] kselftest/arm64: Add very basic GCS test program Mark Brown
2023-07-16 21:51 ` [PATCH 33/35] kselftest/arm64: Add a GCS test program built with the system libc Mark Brown
2023-07-16 21:51 ` [PATCH 34/35] selftests/arm64: Add GCS signal tests Mark Brown
2023-07-16 21:51 ` [PATCH 35/35] kselftest/arm64: Enable GCS for the FP stress tests Mark Brown
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