Re: [PATCH] Revert "kexec/powerpc: Handle buffer overflow in kernel command line"

[Zhang Yanfei <zhangyanfei.yes@gmail.com>]

Hi Simon,

I found that you may apply the patch from Suzuki with a wrong commit
description by mistake. So I send this revert patch and resend the
patch in another mail with a subject:
    "[PATCH RESEND] kexec/powerpc: Handle buffer overflow in kernel command line"

Could you please apply the two patches?

Thanks
Zhang

于 2013年04月16日 20:59, Zhang Yanfei 写道:
> From: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> 
> This reverts commit d58dcae3e61b375578ff3145e627a5d85afb5f52.
> 
> The commit description is kind of wrong and maybe caused by Simon
> when he applied the patch.
> 
> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> ---
>  kexec/arch/ppc/kexec-elf-ppc.c    |   29 +++++++++++++----------------
>  kexec/arch/ppc/kexec-uImage-ppc.c |   23 +++++++++--------------
>  2 files changed, 22 insertions(+), 30 deletions(-)
> 
> diff --git a/kexec/arch/ppc/kexec-elf-ppc.c b/kexec/arch/ppc/kexec-elf-ppc.c
> index 98cae9c..3daca2d 100644
> --- a/kexec/arch/ppc/kexec-elf-ppc.c
> +++ b/kexec/arch/ppc/kexec-elf-ppc.c
> @@ -157,7 +157,7 @@ int elf_ppc_load(int argc, char **argv,	const char *buf, off_t len,
>  	struct mem_ehdr ehdr;
>  	char *command_line, *crash_cmdline, *cmdline_buf;
>  	char *tmp_cmdline;
> -	int command_line_len, crash_cmdline_len;
> +	int command_line_len;
>  	char *dtb;
>  	int result;
>  	char *error_msg;
> @@ -244,10 +244,19 @@ int elf_ppc_load(int argc, char **argv,	const char *buf, off_t len,
>  	} else {
>  		command_line = get_command_line();
>  	}
> -	command_line_len = strlen(command_line);
> +	command_line_len = strlen(command_line) + 1;
>  
>  	fixup_nodes[cur_fixup] = NULL;
>  
> +	/* Need to append some command line parameters internally in case of
> +	 * taking crash dumps.
> +	 */
> +	if (info->kexec_flags & KEXEC_ON_CRASH) {
> +		crash_cmdline = xmalloc(COMMAND_LINE_SIZE);
> +		memset((void *)crash_cmdline, 0, COMMAND_LINE_SIZE);
> +	} else
> +		crash_cmdline = NULL;
> +
>  	/* Parse the Elf file */
>  	result = build_elf_exec_info(buf, len, &ehdr, 0);
>  	if (result < 0) {
> @@ -283,23 +292,16 @@ int elf_ppc_load(int argc, char **argv,	const char *buf, off_t len,
>  		goto out;
>  	}
>  
> -	/*
> -	 * Need to append some command line parameters internally in case of
> -	 * taking crash dumps. Additional segments need to be created.
> +	/* If panic kernel is being loaded, additional segments need
> +	 * to be created.
>  	 */
>  	if (info->kexec_flags & KEXEC_ON_CRASH) {
> -		crash_cmdline = xmalloc(COMMAND_LINE_SIZE);
> -		memset((void *)crash_cmdline, 0, COMMAND_LINE_SIZE);
>  		result = load_crashdump_segments(info, crash_cmdline,
>  						max_addr, 0);
>  		if (result < 0) {
>  			result = -1;
>  			goto out;
>  		}
> -		crash_cmdline_len = strlen(crash_cmdline);
> -	} else {
> -		crash_cmdline = NULL;
> -		crash_cmdline_len = 0;
>  	}
>  
>  	/*
> @@ -335,11 +337,6 @@ int elf_ppc_load(int argc, char **argv,	const char *buf, off_t len,
>  
>  	info->entry = (void *)arg_base;
>  #else
> -	if (crash_cmdline_len + command_line_len + 1 > COMMAND_LINE_SIZE) {
> -		printf("Kernel command line exceeds size\n");
> -		return -1;
> -	}
> -
>  	cmdline_buf = xmalloc(COMMAND_LINE_SIZE);
>  	memset((void *)cmdline_buf, 0, COMMAND_LINE_SIZE);
>  	if (command_line)
> diff --git a/kexec/arch/ppc/kexec-uImage-ppc.c b/kexec/arch/ppc/kexec-uImage-ppc.c
> index 008463b..9113fbe 100644
> --- a/kexec/arch/ppc/kexec-uImage-ppc.c
> +++ b/kexec/arch/ppc/kexec-uImage-ppc.c
> @@ -82,7 +82,7 @@ static int ppc_load_bare_bits(int argc, char **argv, const char *buf,
>  {
>  	char *command_line, *cmdline_buf, *crash_cmdline;
>  	char *tmp_cmdline;
> -	int command_line_len, crash_cmdline_len;
> +	int command_line_len;
>  	char *dtb;
>  	unsigned int addr;
>  	unsigned long dtb_addr;
> @@ -178,34 +178,29 @@ static int ppc_load_bare_bits(int argc, char **argv, const char *buf,
>  
>  	add_segment(info, buf, len, load_addr, len + _1MiB);
>  
> -
>  	if (info->kexec_flags & KEXEC_ON_CRASH) {
>                  crash_cmdline = xmalloc(COMMAND_LINE_SIZE);
>                  memset((void *)crash_cmdline, 0, COMMAND_LINE_SIZE);
> +        } else
> +                crash_cmdline = NULL;
> +
> +	if (info->kexec_flags & KEXEC_ON_CRASH) {
>  		ret = load_crashdump_segments(info, crash_cmdline,
>  						max_addr, 0);
>  		if (ret < 0) {
>  			ret = -1;
>  			goto out;
>  		}
> -		crash_cmdline_len = strlen(crash_cmdline);
> -	} else {
> -		crash_cmdline = NULL;
> -		crash_cmdline_len = 0;
> -	}
> -
> -	if (crash_cmdline_len + command_line_len + 1 > COMMAND_LINE_SIZE) {
> -		printf("Kernel command line exceeds maximum possible length\n");
> -		return -1;
>  	}
>  
>  	cmdline_buf = xmalloc(COMMAND_LINE_SIZE);
>  	memset((void *)cmdline_buf, 0, COMMAND_LINE_SIZE);
> -
>  	if (command_line)
> -		strcpy(cmdline_buf, command_line);
> +		strncat(cmdline_buf, command_line, command_line_len);
>  	if (crash_cmdline)
> -		strncat(cmdline_buf, crash_cmdline, crash_cmdline_len);
> +		strncat(cmdline_buf, crash_cmdline,
> +			sizeof(crash_cmdline) -
> +			strlen(crash_cmdline) - 1);
>  
>  	elf_rel_build_load(info, &info->rhdr, (const char *)purgatory,
>  				purgatory_size, 0, -1, -1, 0);


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