Re: [PATCH RESEND]kexec:i386/kexec-[bzImage|elf-x86]:x86_64/kexec-bzImage64: Use "\0" as command line instead of empty command line

[Zhang Yanfei <zhangyanfei@cn.fujitsu.com>]

于 2013年04月08日 17:23, Wang YanQing 写道:
> This patch prevents the problems to happen below:
> In setup_linux_bootloader_parameters_high
> 120         cmdline_ptr = ((char *)real_mode) + cmdline_offset;
> 121         memcpy(cmdline_ptr, cmdline, cmdline_len);
> 122         cmdline_ptr[cmdline_len - 1] = '\0';
> 
> if cmdline_len == 0, Line 122 will corrupt kernel16 buf just before the commandline.
> And in do_bzImage_load, for example,
> 369         cmdline_end = setup_base + kern16_size_needed + command_line_len - 1;
> 370         elf_rel_set_symbol(&info->rhdr, "cmdline_end", &cmdline_end,
> 371                            sizeof(unsigned long));
> Line 369 will go wrong, too.
> 
> Signed-off-by: Wang YanQing <udknight@gmail.com>
> ---
>  Hi Zhang Yanfei, could you give your signed-off-by to
>  this patch?

Yeah.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>

Hi Simon, could you please take a look at this to see if the change is reasonable?
After all, if no commadline, we make the commandline_len to 1. I don't know if
this behaviour could be accepted by you.

Thanks
Zhang

> 
>  kexec/arch/i386/kexec-bzImage.c     | 3 +++
>  kexec/arch/i386/kexec-elf-x86.c     | 3 +++
>  kexec/arch/x86_64/kexec-bzImage64.c | 6 +++++-
>  3 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/kexec/arch/i386/kexec-bzImage.c b/kexec/arch/i386/kexec-bzImage.c
> index 99fd790..29f280d 100644
> --- a/kexec/arch/i386/kexec-bzImage.c
> +++ b/kexec/arch/i386/kexec-bzImage.c
> @@ -435,6 +435,9 @@ int bzImage_load(int argc, char **argv, const char *buf, off_t len,
>  	command_line_len = 0;
>  	if (command_line) {
>  		command_line_len = strlen(command_line) +1;
> +	} else {
> +	    command_line = strdup("\0");
> +	    command_line_len = 1;
>  	}
>  	ramdisk_buf = 0;
>  	if (ramdisk) {
> diff --git a/kexec/arch/i386/kexec-elf-x86.c b/kexec/arch/i386/kexec-elf-x86.c
> index e62ebcb..788a209 100644
> --- a/kexec/arch/i386/kexec-elf-x86.c
> +++ b/kexec/arch/i386/kexec-elf-x86.c
> @@ -161,6 +161,9 @@ int elf_x86_load(int argc, char **argv, const char *buf, off_t len,
>  	command_line_len = 0;
>  	if (command_line) {
>  		command_line_len = strlen(command_line) +1;
> +	} else {
> +	    command_line = strdup("\0");
> +	    command_line_len = 1;
>  	}
>  
>  	/* Need to append some command line parameters internally in case of
> diff --git a/kexec/arch/x86_64/kexec-bzImage64.c b/kexec/arch/x86_64/kexec-bzImage64.c
> index 86e6d13..ec614a4 100644
> --- a/kexec/arch/x86_64/kexec-bzImage64.c
> +++ b/kexec/arch/x86_64/kexec-bzImage64.c
> @@ -284,8 +284,12 @@ int bzImage64_load(int argc, char **argv, const char *buf, off_t len,
>  	}
>  	command_line = concat_cmdline(command_line, append);
>  	command_line_len = 0;
> -	if (command_line)
> +	if (command_line) {
>  		command_line_len = strlen(command_line) + 1;
> +	} else {
> +		command_line = strdup("\0");
> +		command_line_len = 1;
> +	}
>  	ramdisk_buf = 0;
>  	if (ramdisk)
>  		ramdisk_buf = slurp_file(ramdisk, &ramdisk_length);


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