Re: [Powerpc-utils-devel] [PATCH 2/2] nvram: don't allow long names

[Nathan F. <nf...@li...>]

On 06/09/2015 10:43 PM, Joel Stanley wrote:
> The maximum partition name length is 12 characters but nvram accepts
> strings of any length. This change will enforce the maximum length
> passed to options that take a partition name to avoid confusion.
> 
> Signed-off-by: Joel Stanley <jo...@jm...>
> ---
>  src/nvram.c | 25 +++++++++++++++++++++++++
>  src/nvram.h | 14 ++++++++++----
>  2 files changed, 35 insertions(+), 4 deletions(-)
> 
> diff --git a/src/nvram.c b/src/nvram.c
> index c3f4ebc..b2f5c8c 100644
> --- a/src/nvram.c
> +++ b/src/nvram.c
> @@ -467,6 +467,11 @@ nvram_find_fd_partition(struct nvram *nvram, char *name)
>      int				len;
>      int				found = 0;
> 
> +    if (strlen(name) > MAX_PART_NAME) {
> +        err_msg("partition name too long\n");
> +        return -1;
> +    }
> +

Any reason for not making this a function for here (and below) instead of
copying the code in every place?

-Nathan

>      if (lseek(nvram->fd, SEEK_SET, 0) == -1) {
>          err_msg("could not seek to beginning of file %s\n", nvram->filename);
>  	return -1;
> @@ -1461,12 +1466,27 @@ main (int argc, char *argv[])
>  		break;
>  	    case 'd':	/* dump */
>  		dump_name = optarg;
> +		if (strlen(dump_name) > MAX_PART_NAME) {
> +			err_msg("partition name maximum length is %d\n",
> +					MAX_PART_NAME);
> +			exit(1);
> +		}
>  		break;
>  	    case 'a':	/* ASCII dump */
>  	    	ascii_name = optarg;
> +		if (strlen(ascii_name) > MAX_PART_NAME) {
> +			err_msg("partition name maximum length is %d\n",
> +					MAX_PART_NAME);
> +			exit(1);
> +		}
>  		break;
>  	    case 'z':	/* dump compressed data */
>  		zip_name = optarg;
> +		if (strlen(zip_name) > MAX_PART_NAME) {
> +			err_msg("partition name maximum length is %d\n",
> +					MAX_PART_NAME);
> +			exit(1);
> +		}
>  		break;
>  	    case 'n':	/* nvram-file */
>  		nvram.filename = optarg;
> @@ -1509,6 +1529,11 @@ main (int argc, char *argv[])
>  		break;
>  	    case 'p':	/* update-config partition name */
>  	        config_pname = optarg;
> +		if (strlen(config_pname) > MAX_PART_NAME) {
> +			err_msg("partition name maximum length is %d\n",
> +					MAX_PART_NAME);
> +			exit(1);
> +		}
>  		break;
>  	    case '?':
>  		exit(1);
> diff --git a/src/nvram.h b/src/nvram.h
> index b4961fe..b78e793 100644
> --- a/src/nvram.h
> +++ b/src/nvram.h
> @@ -45,14 +45,20 @@
>  #define MAX_CPUS 128
> 
>  /**
> + * @def MAX_PART_NAME
> + * @brief maximum number of bytes in partition name
> + */
> +#define MAX_PART_NAME 12
> +
> +/**
>   * @struct partition_header
>   * @brief nvram partition header data
>   */
>  struct partition_header {
> -    unsigned char	signature;  /**< partition signature */
> -    unsigned char 	checksum;   /**< partition checksum */
> -    unsigned short 	length;     /**< partition length */
> -    char 		name[12];   /**< partition name */
> +    unsigned char	signature;		/**< partition signature */
> +    unsigned char 	checksum;		/**< partition checksum */
> +    unsigned short 	length;			/**< partition length */
> +    char 		name[MAX_PART_NAME];	/**< partition name */
>  };
> 
>  /* sub-header for error-log partitions */
>