linux-kernel - Re: [RFC PATCH v0 00/19] x86/insn: Add an insn

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20201202180456.GH2951@zn.tnic>
Date:   Wed, 2 Dec 2020 19:04:56 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Masami Hiramatsu <mhiramat@...nel.org>
Cc:     Andy Lutomirski <luto@...capital.net>, X86 ML <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH v0 00/19] x86/insn: Add an insn_decode() API

On Tue, Dec 01, 2020 at 02:21:45AM +0900, Masami Hiramatsu wrote:
> Because it overruns the buffer. Maybe -E2BIG/ENODATA or any other
> error (except for -EINVAL) is OK :)

ENODATA it is. :)

And propagating that error value is easy because the err_out: labels are
all coming from the validate_next() error path so we basically know that
the buffer has ended.

./insn_sanity: Success: decoded and checked 10000 random instructions with 0 errors (seed:0x7bdfa56e)
insn buffer:
0x48 0xcf 0x48 0x83 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 
supplied buf size: 15, ret 0
supplied buf size: 2, ret 0
supplied buf size: 3, ret 0
supplied buf size: 4, ret 0
insn_decode: entry
insn_decode: will get_length
insn_get_immediate: getting immediate
insn_get_displacement: getting displacement
insn_get_sib: getting sib
insn_get_modrm: entry
insn_get_opcode: entry
insn_get_prefixes: entry, prefixes->got: 0
insn_get_prefixes: 1
insn_get_prefixes: REX
insn_get_prefixes: VEX
insn_get_prefixes: validate_next: 0
insn_get_prefixes: insn->next_byte: 0x7ffc211eb661, insn->end_kaddr: 0x7ffc211eb661
insn_get_prefixes: errored out
supplied buf size: 1, ret -61

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette