linux-kernel - Re: [PATCH 02/02] x86_64: Add safe check in a.out loaders and some coding style

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Date:	Wed, 18 Sep 2013 19:38:36 -0300
From:	Geyslan Gregório Bem <geyslan@...il.com>
To:	viro@...iv.linux.org.uk, linux-fsdevel@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, "Geyslan G. Bem" <geyslan@...il.com>
Subject: Re: [PATCH 02/02] x86_64: Add safe check in a.out loaders and some
 coding style

Please, disregard this due to problems reversing the commit.

I'll send the entire one soon.

Geyslan Gregório Bem
hackingbits.com


2013/9/18 Geyslan G. Bem <geyslan@...il.com>:
> ia32_aout had no safe checks concerning the mmap and f_op in this module.
> It's not necessary to verify f_op in the load_aout_library, since the
> prior kernel_read/vfs_read function already does.
> Coding style and printks fixes.
>
> Tested using qemu, a handcrafted a.out binary and a a.out linked with a
> cross-compiled ld.
>
> Signed-off-by: Geyslan G. Bem <geyslan@...il.com>
> ---
>  arch/x86/ia32/ia32_aout.c | 25 ++++++-------------------
>  1 file changed, 6 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c
> index 15a8319..46a0346 100644
> --- a/arch/x86/ia32/ia32_aout.c
> +++ b/arch/x86/ia32/ia32_aout.c
> @@ -24,7 +24,7 @@
>  #include <linux/binfmts.h>
>  #include <linux/personality.h>
>  #include <linux/init.h>
> -#include <linux/jiffies.h>
> +#include <linux/ratelimit.h>
>
>  #include <asm/uaccess.h>
>  #include <asm/pgalloc.h>
> @@ -346,21 +346,13 @@ static int load_aout_binary(struct linux_binprm *bprm)
>                 }
>         } else {
>  #ifdef WARN_OLD
> -               static unsigned long error_time, error_time2;
>                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
> -                   (N_MAGIC(ex) != NMAGIC) &&
> -                               time_after(jiffies, error_time2 + 5*HZ)) {
> -                       printk(KERN_NOTICE "executable not page aligned\n");
> -                       error_time2 = jiffies;
> -               }
> +                   (N_MAGIC(ex) != NMAGIC))
> +                       pr_notice_ratelimited("executable not page aligned\n");
>
> -               if ((fd_offset & ~PAGE_MASK) != 0 &&
> -                           time_after(jiffies, error_time + 5*HZ)) {
> -                       printk(KERN_WARNING
> -                              "fd_offset is not page aligned. Please convert program: %s\n",
> +               if ((fd_offset & ~PAGE_MASK) != 0)
> +                       pr_warn_ratelimited("fd_offset is not page aligned. Please convert program: %s\n",
>                                bprm->file->f_path.dentry->d_name.name);
> -                       error_time = jiffies;
> -               }
>  #endif
>
>                 if ((fd_offset & ~PAGE_MASK) != 0) {
> @@ -451,13 +443,8 @@ static int load_aout_library(struct file *file)
>
>         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
>  #ifdef WARN_OLD
> -               static unsigned long error_time;
> -               if (time_after(jiffies, error_time + 5*HZ)) {
> -                       printk(KERN_WARNING
> -                              "N_TXTOFF is not page aligned. Please convert library: %s\n",
> +               pr_warn_ratelimited("N_TXTOFF is not page aligned. Please convert library: %s\n",
>                                file->f_path.dentry->d_name.name);
> -                       error_time = jiffies;
> -               }
>  #endif
>                 vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
>
> --
> 1.8.4
>
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