From: Josh Poimboeuf <jpoimboe@kernel.org>
To: Ard Biesheuvel <ardb+git@google.com>
Cc: linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
keescook@chromium.org, linux-hardening@vger.kernel.org,
nathan@kernel.org, Ard Biesheuvel <ardb@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Jan Beulich <jbeulich@suse.com>,
"Jose E. Marchesi" <jemarch@gnu.org>, Kees Cook <kees@kernel.org>
Subject: Re: [PATCH v2 5/5] crypto: x86/crc32c - Tweak jump table to validate objtool logic
Date: Thu, 10 Oct 2024 13:34:01 -0700 [thread overview]
Message-ID: <20241010203401.45ds362dpx52ne5z@treble> (raw)
In-Reply-To: <20241010122801.1321976-12-ardb+git@google.com>
On Thu, Oct 10, 2024 at 02:28:07PM +0200, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
>
> Tweak the jump table so
> - the address is taken far way from its use
> - its offset from the start of .rodata is != 0x0
> - its type is STT_OBJECT and its size is set to the size of the actual
> table
> - the indirect jump is annotated with a R_X86_64_NONE relocation
> pointing to the jump table
>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This needs more "why", I assume the goals are to add the annotations +
confuse objtool if it doesn't read them properly?
--
Josh
next prev parent reply other threads:[~2024-10-10 20:34 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-10 12:28 [PATCH v2 0/5] Improve objtool jump table handling Ard Biesheuvel
2024-10-10 12:28 ` [PATCH v2 1/5] objtool: Deal with relative jump tables correctly Ard Biesheuvel
2024-10-10 13:26 ` Peter Zijlstra
2024-10-10 13:59 ` Ard Biesheuvel
2024-10-10 14:07 ` Peter Zijlstra
2024-10-10 15:32 ` Josh Poimboeuf
2024-10-10 12:28 ` [PATCH v2 2/5] objtool: Allow arch code to discover jump table size Ard Biesheuvel
2024-10-10 19:52 ` Josh Poimboeuf
2024-10-11 16:50 ` Ard Biesheuvel
2024-10-10 12:28 ` [PATCH v2 3/5] objtool: Add support for annotated jump tables Ard Biesheuvel
2024-10-10 20:12 ` Josh Poimboeuf
2024-10-10 20:15 ` Josh Poimboeuf
2024-10-11 6:29 ` Ard Biesheuvel
2024-10-11 15:56 ` Josh Poimboeuf
2024-10-10 12:28 ` [PATCH v2 4/5] crypto: x86/crc32c - Use idiomatic relative jump table Ard Biesheuvel
2024-10-10 12:28 ` [PATCH v2 5/5] crypto: x86/crc32c - Tweak jump table to validate objtool logic Ard Biesheuvel
2024-10-10 20:34 ` Josh Poimboeuf [this message]
2024-10-11 6:32 ` Ard Biesheuvel
2024-10-11 16:04 ` Josh Poimboeuf
2024-10-11 16:22 ` Ard Biesheuvel
2024-10-10 17:50 ` [PATCH v2 0/5] Improve objtool jump table handling Ard Biesheuvel
2024-10-10 20:36 ` Josh Poimboeuf
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