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Subject[RFC PATCH v2 10/18] hfs: Do not use broken utf8 NLS table for iocharset=utf8 mount option
Date
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 cea19ed06bce..5a63df41da05 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);
- 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;
+ bool have_iocharset;

/* 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 = false;
+
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 = true;
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) {
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 dbf535d52d37..01f37b395f10 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;

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 && dstlen > 0) {
- size = nls_io->char2uni(src, srclen, &ch);
+ if (nls_io)
+ size = nls_io->char2uni(src, srclen, &ch);
+ else {
+ size = utf8_to_utf32(src, srclen, &u);
+ if (size >= 0) {
+ if (u <= MAX_WCHAR_T)
+ ch = u;
+ else
+ size = -EINVAL;
+ }
+ }
if (size < 0) {
ch = '?';
size = 1;
--
2.20.1
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