Re: [PATCH] x86: Remove a.out support

From: Kees Cook <keescook@chromium.org>
To: James Jones <linux@theinnocuous.com>
Cc: bp@alien8.de, x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: Remove a.out support
Date: Tue, 15 Mar 2022 12:51:52 -0700	[thread overview]
Message-ID: <202203151150.1CDB1D8DA@keescook> (raw)
In-Reply-To: <0b31b1d3-852d-6cab-82ae-5eecaec05679@theinnocuous.com>

On Sat, Mar 12, 2022 at 06:06:26PM +0000, James Jones wrote:
> [...]
> > docs, including copies of the old mac and aln a.out binaries, is
> > available here:
> >
> > https://github.com/cubanismo/jaguar-sdk

Do these end up requiring libc4, etc? I see "uselib" syscalls in the
disassembly...

$ for i in $(objdump -b binary -D -m i386 aln mac | grep -B4 'int.*$0x80' \
	| grep -E 'int|eax' | grep mov | awk '{print $8}' | cut -d, -f1 \
	| cut -c2- | sort -u); do printf "%d\n" $i; done | sort -n
1       exit
3       read
4       write
5       open
6       close
10      unlink
13      time
19      lseek
20      getpid
37      kill
45      brk
54      ioctl
55      fcntl
86      uselib
89      readdir
91      munmap
106     stat
107     lstat
108     fstat
126     sigprocmask

It seems like it should be possible to create an ELF wrapper for simple
a.out binaries...

-- 
Kees Cook