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

From: Viacheslav Dubeyko
Date: Mon Aug 09 2021 - 13:49:44 EST




> On Aug 8, 2021, at 9:24 AM, Pali Rohár <pali@xxxxxxxxxx> 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@xxxxxxxxxx>
> ---
> 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
>