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Message-ID: <Yzy+jUeCXpYI6QvL@kernel.org>
Date: Wed, 5 Oct 2022 02:15:25 +0300
From: Jarkko Sakkinen <jarkko@...nel.org>
To: Borys <borysp@...isiblethingslab.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
linux-sgx@...r.kernel.org, linux-kernel@...r.kernel.org,
Reinette Chatre <reinette.chatre@...el.com>,
Michał Kowalczyk <mkow@...isiblethingslab.com>
Subject: Re: [PATCH] x86/sgx: Add overflow check in
sgx_validate_offset_length()
On Wed, Oct 05, 2022 at 12:59:03AM +0200, Borys wrote:
> sgx_validate_offset_length() function verifies "offset" and "length"
> arguments provided by userspace, but was missing an overflow check on
> their addition.
> This code was originally introduced in commit c6d26d370767 ("x86/sgx:
> Add SGX_IOC_ENCLAVE_ADD_PAGES") and later refactored in commit
> dda03e2c331b ("x86/sgx: Create utility to validate user provided offset
> and length").
>
> Fixes: c6d26d370767 ("x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES")
> Signed-off-by: Borys Popławski <borysp@...isiblethingslab.com>
> ---
> Applies on top of tip/x86/sgx ee56a283988d739c25d2d00ffb22707cb487ab47
>
> arch/x86/kernel/cpu/sgx/ioctl.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> index ebe79d60619f..da8b8ea6b063 100644
> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -356,6 +356,9 @@ static int sgx_validate_offset_length(struct sgx_encl *encl,
> if (!length || !IS_ALIGNED(length, PAGE_SIZE))
> return -EINVAL;
>
> + if (offset + length < offset)
> + return -EINVAL;
> +
> if (offset + length - PAGE_SIZE >= encl->size)
> return -EINVAL;
>
> --
> 2.37.3
>
Thank you.
Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>
BTW, needs:
Cc: stable@...r.kernel.org # v5.11+
BR, Jarkko
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