Re: [PATCH 06/17] mkfs: validate logarithmic parameters sanely

[Brian Foster <bfoster@redhat.com>]

On Fri, Jun 19, 2015 at 01:01:55PM +0200, Jan Ťulák wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Testing logarithmic paramters like "-n log=<num>" shows that we do a
> terrible job of validating such input. e.g.:
> 
> # mkfs.xfs -f -n log=456858480 /dev/vda
> .....
> naming   =version 2              bsize=65536  ascii-ci=0 ftype=0
> ....
> 
> Yeah, I just asked for a block size of 2^456858480, and it didn't
> get rejected. Great, isn't it?
> 
> So, factor out the parsing of logarithmic parameters, and pass in
> the maximum valid value that they can take. These maximum values
> might not be completely accurate (e.g. block/sector sizes will
> affect the eventual valid maximum) but we can get rid of all the
> overflows and stupidities before we get to fine-grained validity
> checking later in mkfs once things like block and sector sizes have
> been finalised.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Signed-off-by: Jan Ťulák <jtulak@redhat.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  mkfs/xfs_mkfs.c | 79 +++++++++++++++++++++++++++++++++++++--------------------
>  1 file changed, 51 insertions(+), 28 deletions(-)
> 
> diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> index 6b9e991..6f0aa55 100644
> --- a/mkfs/xfs_mkfs.c
> +++ b/mkfs/xfs_mkfs.c
> @@ -1044,6 +1044,27 @@ getbool(
>  	return c ? true : false;
>  }
>  
> +static int
> +getnum_checked(
> +	const char	*str,
> +	long long	min_val,
> +	long long	max_val,
> +	const char	*illegal_str,
> +	char		reqval_char,
> +	char		*reqval_opts[],
> +	int		reqval_optind)
> +{
> +	long long	c;
> +
> +	if (!str || *str == '\0')
> +		reqval(reqval_char, reqval_opts, reqval_optind);
> +
> +	c = getnum(str, 0, 0, false);
> +	if (c < min_val || c > max_val)
> +		illegal(str, illegal_str);
> +	return c;
> +}
> +
>  int
>  main(
>  	int			argc,
> @@ -1200,16 +1221,16 @@ main(
>  
>  				switch (getsubopt(&p, (constpp)bopts, &value)) {
>  				case B_LOG:
> -					if (!value || *value == '\0')
> -						reqval('b', bopts, B_LOG);
>  					if (blflag)
>  						respec('b', bopts, B_LOG);
>  					if (bsflag)
>  						conflict('b', bopts, B_SIZE,
>  							 B_LOG);
> -					blocklog = getnum(value, 0, 0, false);
> -					if (blocklog <= 0)
> -						illegal(value, "b log");
> +					blocklog = getnum_checked(value,
> +							XFS_MIN_BLOCKSIZE_LOG,
> +							XFS_MAX_BLOCKSIZE_LOG,
> +							"b log", 'b', bopts,
> +							B_LOG);
>  					blocksize = 1 << blocklog;
>  					blflag = 1;
>  					break;
> @@ -1346,16 +1367,16 @@ main(
>  					nodsflag = 1;
>  					break;
>  				case D_SECTLOG:
> -					if (!value || *value == '\0')
> -						reqval('d', dopts, D_SECTLOG);
>  					if (slflag)
>  						respec('d', dopts, D_SECTLOG);
>  					if (ssflag)
>  						conflict('d', dopts, D_SECTSIZE,
>  							 D_SECTLOG);
> -					sectorlog = getnum(value, 0, 0, false);
> -					if (sectorlog <= 0)
> -						illegal(value, "d sectlog");
> +					sectorlog = getnum_checked(value,
> +							XFS_MIN_SECTORSIZE_LOG,
> +							XFS_MAX_SECTORSIZE_LOG,
> +							"d sectlog", 'd', dopts,
> +							D_SECTLOG);
>  					sectorsize = 1 << sectorlog;
>  					slflag = 1;
>  					break;
> @@ -1420,9 +1441,11 @@ main(
>  					if (isflag)
>  						conflict('i', iopts, I_SIZE,
>  							 I_LOG);
> -					inodelog = getnum(value, 0, 0, false);
> -					if (inodelog <= 0)
> -						illegal(value, "i log");
> +					inodelog = getnum_checked(value,
> +							XFS_DINODE_MIN_LOG,
> +							XFS_DINODE_MAX_LOG,
> +							"i log", 'i', iopts,
> +							I_LOG);
>  					isize = 1 << inodelog;
>  					ilflag = 1;
>  					break;
> @@ -1591,16 +1614,16 @@ main(
>  					lsflag = 1;
>  					break;
>  				case L_SECTLOG:
> -					if (!value || *value == '\0')
> -						reqval('l', lopts, L_SECTLOG);
>  					if (lslflag)
>  						respec('l', lopts, L_SECTLOG);
>  					if (lssflag)
>  						conflict('l', lopts, L_SECTSIZE,
>  							 L_SECTLOG);
> -					lsectorlog = getnum(value, 0, 0, false);
> -					if (lsectorlog <= 0)
> -						illegal(value, "l sectlog");
> +					lsectorlog = getnum_checked(value,
> +							XFS_MIN_SECTORSIZE_LOG,
> +							XFS_MAX_SECTORSIZE_LOG,
> +							"l sectlog", 'l', lopts,
> +							L_SECTLOG);
>  					lsectorsize = 1 << lsectorlog;
>  					lslflag = 1;
>  					break;
> @@ -1673,16 +1696,16 @@ _("cannot specify both -m crc=1 and -n ftype\n"));
>  
>  				switch (getsubopt(&p, (constpp)nopts, &value)) {
>  				case N_LOG:
> -					if (!value || *value == '\0')
> -						reqval('n', nopts, N_LOG);
>  					if (nlflag)
>  						respec('n', nopts, N_LOG);
>  					if (nsflag)
>  						conflict('n', nopts, N_SIZE,
>  							 N_LOG);
> -					dirblocklog = getnum(value, 0, 0, false);
> -					if (dirblocklog <= 0)
> -						illegal(value, "n log");
> +					dirblocklog = getnum_checked(value,
> +							XFS_MIN_REC_DIRSIZE,
> +							XFS_MAX_BLOCKSIZE_LOG,
> +							"n log", 'n', nopts,
> +							N_LOG);
>  					dirblocksize = 1 << dirblocklog;
>  					nlflag = 1;
>  					break;
> @@ -1801,16 +1824,16 @@ _("cannot specify both -m crc=1 and -n ftype\n"));
>  				switch (getsubopt(&p, (constpp)sopts, &value)) {
>  				case S_LOG:
>  				case S_SECTLOG:
> -					if (!value || *value == '\0')
> -						reqval('s', sopts, S_SECTLOG);
>  					if (slflag || lslflag)
>  						respec('s', sopts, S_SECTLOG);
>  					if (ssflag || lssflag)
>  						conflict('s', sopts, S_SECTSIZE,
>  							 S_SECTLOG);
> -					sectorlog = getnum(value, 0, 0, false);
> -					if (sectorlog <= 0)
> -						illegal(value, "s sectlog");
> +					sectorlog = getnum_checked(value,
> +							XFS_MIN_SECTORSIZE_LOG,
> +							XFS_MAX_SECTORSIZE_LOG,
> +							"s sectlog", 's', sopts,
> +							S_SECTLOG);
>  					lsectorlog = sectorlog;
>  					sectorsize = 1 << sectorlog;
>  					lsectorsize = sectorsize;
> -- 
> 2.1.0
> 
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