From afd6c9e1f5287ad236adcf56db8c42fef65561fa Mon Sep 17 00:00:00 2001 From: "Ernesto A. Fernández" Date: Tue, 21 Aug 2018 21:59:19 -0700 Subject: hfsplus: fix decomposition of Hangul characters MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Files created under macOS cannot be opened under linux if their names contain Korean characters, and vice versa. The Korean alphabet is special because its normalization is done without a table. The module deals with it correctly when composing, but forgets about it for the decomposition. Fix this using the Hangul decomposition function provided in the Unicode Standard. The code fits a bit awkwardly because it requires a buffer, while all the other normalizations are returned as pointers to the decomposition table. This is actually also a bug because reordering may still be needed, but for now leave it as it is. The patch will cause trouble for Hangul filenames already created by the module in the past. This shouldn't really be concern because its main purpose was always sharing with macOS. If a user actually needs to access such a file the nodecompose mount option should be enough. Link: http://lkml.kernel.org/r/20180717220951.p6qqrgautc4pxvzu@eaf Signed-off-by: Ernesto A. Fernández Reported-by: Ting-Chang Hou Tested-by: Ting-Chang Hou Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/hfsplus/unicode.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 56 insertions(+), 6 deletions(-) diff --git a/fs/hfsplus/unicode.c b/fs/hfsplus/unicode.c index dfa90c21948f..c8d1b2be7854 100644 --- a/fs/hfsplus/unicode.c +++ b/fs/hfsplus/unicode.c @@ -272,8 +272,8 @@ static inline int asc2unichar(struct super_block *sb, const char *astr, int len, return size; } -/* Decomposes a single unicode character. */ -static inline u16 *decompose_unichar(wchar_t uc, int *size) +/* Decomposes a non-Hangul unicode character. */ +static u16 *hfsplus_decompose_nonhangul(wchar_t uc, int *size) { int off; @@ -296,6 +296,51 @@ static inline u16 *decompose_unichar(wchar_t uc, int *size) return hfsplus_decompose_table + (off / 4); } +/* + * Try to decompose a unicode character as Hangul. Return 0 if @uc is not + * precomposed Hangul, otherwise return the length of the decomposition. + * + * This function was adapted from sample code from the Unicode Standard + * Annex #15: Unicode Normalization Forms, version 3.2.0. + * + * Copyright (C) 1991-2018 Unicode, Inc. All rights reserved. Distributed + * under the Terms of Use in http://www.unicode.org/copyright.html. + */ +static int hfsplus_try_decompose_hangul(wchar_t uc, u16 *result) +{ + int index; + int l, v, t; + + index = uc - Hangul_SBase; + if (index < 0 || index >= Hangul_SCount) + return 0; + + l = Hangul_LBase + index / Hangul_NCount; + v = Hangul_VBase + (index % Hangul_NCount) / Hangul_TCount; + t = Hangul_TBase + index % Hangul_TCount; + + result[0] = l; + result[1] = v; + if (t != Hangul_TBase) { + result[2] = t; + return 3; + } + return 2; +} + +/* Decomposes a single unicode character. */ +static u16 *decompose_unichar(wchar_t uc, int *size, u16 *hangul_buffer) +{ + u16 *result; + + /* Hangul is handled separately */ + result = hangul_buffer; + *size = hfsplus_try_decompose_hangul(uc, result); + if (*size == 0) + result = hfsplus_decompose_nonhangul(uc, size); + return result; +} + int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr, int max_unistr_len, const char *astr, int len) @@ -303,13 +348,14 @@ int hfsplus_asc2uni(struct super_block *sb, int size, dsize, decompose; u16 *dstr, outlen = 0; wchar_t c; + u16 dhangul[3]; decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags); while (outlen < max_unistr_len && len > 0) { size = asc2unichar(sb, astr, len, &c); if (decompose) - dstr = decompose_unichar(c, &dsize); + dstr = decompose_unichar(c, &dsize, dhangul); else dstr = NULL; if (dstr) { @@ -344,6 +390,7 @@ int hfsplus_hash_dentry(const struct dentry *dentry, struct qstr *str) unsigned long hash; wchar_t c; u16 c2; + u16 dhangul[3]; casefold = test_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags); decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags); @@ -357,7 +404,7 @@ int hfsplus_hash_dentry(const struct dentry *dentry, struct qstr *str) len -= size; if (decompose) - dstr = decompose_unichar(c, &dsize); + dstr = decompose_unichar(c, &dsize, dhangul); else dstr = NULL; if (dstr) { @@ -396,6 +443,7 @@ int hfsplus_compare_dentry(const struct dentry *dentry, const char *astr1, *astr2; u16 c1, c2; wchar_t c; + u16 dhangul_1[3], dhangul_2[3]; casefold = test_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags); decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags); @@ -413,7 +461,8 @@ int hfsplus_compare_dentry(const struct dentry *dentry, len1 -= size; if (decompose) - dstr1 = decompose_unichar(c, &dsize1); + dstr1 = decompose_unichar(c, &dsize1, + dhangul_1); if (!decompose || !dstr1) { c1 = c; dstr1 = &c1; @@ -427,7 +476,8 @@ int hfsplus_compare_dentry(const struct dentry *dentry, len2 -= size; if (decompose) - dstr2 = decompose_unichar(c, &dsize2); + dstr2 = decompose_unichar(c, &dsize2, + dhangul_2); if (!decompose || !dstr2) { c2 = c; dstr2 = &c2; -- cgit v1.2.3