Re: [RFC PATCH 12/20] hfs: Do not use broken utf8 NLS table for iocharset=utf8 mount option

[Viacheslav Dubeyko <slava@dubeyko.com>]

> On Aug 8, 2021, at 9:24 AM, Pali Rohár <pali@kernel.org> wrote:
> 
> NLS table for utf8 is broken and cannot be fixed.
> 
> So instead of broken utf8 nls functions char2uni() and uni2char() use
> functions utf8_to_utf32() and utf32_to_utf8() which implements correct
> encoding and decoding between Unicode code points and UTF-8 sequence.
> 
> When iochatset=utf8 is used then set hsb->nls_io to NULL and use it for
> distinguish between the fact if NLS table or native UTF-8 functions should
> be used.
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> ---
> fs/hfs/super.c | 33 ++++++++++++++++++++++-----------
> fs/hfs/trans.c | 24 ++++++++++++++++++++----
> 2 files changed, 42 insertions(+), 15 deletions(-)
> 
> diff --git a/fs/hfs/super.c b/fs/hfs/super.c
> index 86bc46746c7f..076308df41cf 100644
> --- a/fs/hfs/super.c
> +++ b/fs/hfs/super.c
> @@ -149,10 +149,13 @@ static int hfs_show_options(struct seq_file *seq, struct dentry *root)
> 		seq_printf(seq, ",part=%u", sbi->part);
> 	if (sbi->session >= 0)
> 		seq_printf(seq, ",session=%u", sbi->session);
> -	if (sbi->nls_disk)
> +	if (sbi->nls_disk) {
> 		seq_printf(seq, ",codepage=%s", sbi->nls_disk->charset);

Maybe, I am missing something. But where is the closing “}”?


> -	if (sbi->nls_io)
> -		seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
> +		if (sbi->nls_io)
> +			seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
> +		else
> +			seq_puts(seq, ",iocharset=utf8");
> +	}
> 	if (sbi->s_quiet)
> 		seq_printf(seq, ",quiet");
> 	return 0;
> @@ -225,6 +228,7 @@ static int parse_options(char *options, struct hfs_sb_info *hsb)
> 	char *p;
> 	substring_t args[MAX_OPT_ARGS];
> 	int tmp, token;
> +	int have_iocharset;

What’s about boolean type?

> 
> 	/* initialize the sb with defaults */
> 	hsb->s_uid = current_uid();
> @@ -239,6 +243,8 @@ static int parse_options(char *options, struct hfs_sb_info *hsb)
> 	if (!options)
> 		return 1;
> 
> +	have_iocharset = 0;

What’s about false here?

> +
> 	while ((p = strsep(&options, ",")) != NULL) {
> 		if (!*p)
> 			continue;
> @@ -332,18 +338,22 @@ static int parse_options(char *options, struct hfs_sb_info *hsb)
> 			kfree(p);
> 			break;
> 		case opt_iocharset:
> -			if (hsb->nls_io) {
> +			if (have_iocharset) {
> 				pr_err("unable to change iocharset\n");
> 				return 0;
> 			}
> 			p = match_strdup(&args[0]);
> -			if (p)
> -				hsb->nls_io = load_nls(p);
> -			if (!hsb->nls_io) {
> -				pr_err("unable to load iocharset \"%s\"\n", p);
> -				kfree(p);
> +			if (!p)
> 				return 0;
> +			if (strcmp(p, "utf8") != 0) {
> +				hsb->nls_io = load_nls(p);
> +				if (!hsb->nls_io) {
> +					pr_err("unable to load iocharset \"%s\"\n", p);
> +					kfree(p);
> +					return 0;
> +				}
> 			}
> +			have_iocharset = 1;

What’s about true here?

> 			kfree(p);
> 			break;
> 		default:
> @@ -351,7 +361,7 @@ static int parse_options(char *options, struct hfs_sb_info *hsb)
> 		}
> 	}
> 
> -	if (hsb->nls_io && !hsb->nls_disk) {
> +	if (have_iocharset && !hsb->nls_disk) {
> 		/*
> 		 * Previous version of hfs driver did something unexpected:
> 		 * When codepage was not defined but iocharset was then
> @@ -382,7 +392,8 @@ static int parse_options(char *options, struct hfs_sb_info *hsb)
> 			return 0;
> 		}
> 	}
> -	if (hsb->nls_disk && !hsb->nls_io) {
> +	if (hsb->nls_disk &&
> +	    !have_iocharset && strcmp(CONFIG_NLS_DEFAULT, "utf8") != 0) {

Maybe, introduce the variable to calculate the boolean value here? Then if statement will look much cleaner.

> 		hsb->nls_io = load_nls_default();
> 		if (!hsb->nls_io) {
> 			pr_err("unable to load default iocharset\n");
> diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c
> index c75682c61b06..bff8e54003ab 100644
> --- a/fs/hfs/trans.c
> +++ b/fs/hfs/trans.c
> @@ -44,7 +44,7 @@ int hfs_mac2asc(struct super_block *sb, char *out, const struct hfs_name *in)
> 		srclen = HFS_NAMELEN;
> 	dst = out;
> 	dstlen = HFS_MAX_NAMELEN;
> -	if (nls_io) {
> +	if (nls_disk) {
> 		wchar_t ch;
> 

I could miss something here. But what’s about the closing “}”?

Thanks,
Slava.

> 		while (srclen > 0) {
> @@ -57,7 +57,12 @@ int hfs_mac2asc(struct super_block *sb, char *out, const struct hfs_name *in)
> 			srclen -= size;
> 			if (ch == '/')
> 				ch = ':';
> -			size = nls_io->uni2char(ch, dst, dstlen);
> +			if (nls_io)
> +				size = nls_io->uni2char(ch, dst, dstlen);
> +			else if (dstlen > 0)
> +				size = utf32_to_utf8(ch, dst, dstlen);
> +			else
> +				size = -ENAMETOOLONG;
> 			if (size < 0) {
> 				if (size == -ENAMETOOLONG)
> 					goto out;
> @@ -101,11 +106,22 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr
> 	srclen = in->len;
> 	dst = out->name;
> 	dstlen = HFS_NAMELEN;
> -	if (nls_io) {
> +	if (nls_disk) {
> 		wchar_t ch;
> +		unicode_t u;
> 
> 		while (srclen > 0) {
> -			size = nls_io->char2uni(src, srclen, &ch);
> +			if (nls_io)
> +				size = nls_io->char2uni(src, srclen, &ch);
> +			else {
> +				size = utf8_to_utf32(str, strlen, &u);
> +				if (size >= 0) {
> +					if (u <= MAX_WCHAR_T)
> +						ch = u;
> +					else
> +						size = -EINVAL;
> +				}
> +			}
> 			if (size < 0) {
> 				ch = '?';
> 				size = 1;
> -- 
> 2.20.1
>