Do not interpret nor emit invalid Unicode encoding forms
Surrogates are invalid in both UTF-32 and UTF-8. See https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G28875 and https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G31703master
parent
5fbffaf035
commit
183761ac24
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@ -41,6 +41,8 @@
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#include "utils.h"
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#include "utf8.h"
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#define NO_KEYSYM_UNICODE_CONVERSION 0
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/* We don't use the uint32_t types here, to save some space. */
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struct codepair {
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uint16_t keysym;
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@ -847,7 +849,7 @@ bin_search(const struct codepair *table, size_t length, xkb_keysym_t keysym)
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}
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/* no matching Unicode value found in table */
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return 0;
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return NO_KEYSYM_UNICODE_CONVERSION;
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}
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XKB_EXPORT uint32_t
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@ -871,6 +873,13 @@ xkb_keysym_to_utf32(xkb_keysym_t keysym)
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return keysym & 0x7f;
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/* also check for directly encoded Unicode codepoints */
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/* Exclude surrogates: they are invalid in UTF-32.
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* See https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G28875
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* for further details.
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*/
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if (0x0100d800 <= keysym && keysym <= 0x0100dfff)
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return NO_KEYSYM_UNICODE_CONVERSION;
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/*
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* In theory, this is supposed to start from 0x100100, such that the ASCII
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* range, which is already covered by 0x00-0xff, can't be encoded in two
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@ -900,7 +909,8 @@ xkb_utf32_to_keysym(uint32_t ucs)
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return XKB_KEY_Delete;
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/* Unicode non-symbols and code points outside Unicode planes */
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if ((ucs >= 0xfdd0 && ucs <= 0xfdef) ||
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if ((ucs >= 0xd800 && ucs <= 0xdfff) ||
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(ucs >= 0xfdd0 && ucs <= 0xfdef) ||
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ucs > 0x10ffff || (ucs & 0xfffe) == 0xfffe)
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return XKB_KEY_NoSymbol;
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@ -948,7 +958,7 @@ xkb_keysym_to_utf8(xkb_keysym_t keysym, char *buffer, size_t size)
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codepoint = xkb_keysym_to_utf32(keysym);
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if (codepoint == 0)
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if (codepoint == NO_KEYSYM_UNICODE_CONVERSION)
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return 0;
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return utf32_to_utf8(codepoint, buffer);
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16
src/utf8.c
16
src/utf8.c
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@ -32,6 +32,11 @@
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#include "utf8.h"
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/* Conformant encoding form conversion from UTF-32 to UTF-8.
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*
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* See https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G28875
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* for further details.
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*/
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int
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utf32_to_utf8(uint32_t unichar, char *buffer)
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{
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length = 2;
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head = 0xc0;
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}
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/* Handle surrogates */
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else if (0xd800 <= unichar && unichar <= 0xdfff) {
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goto ill_formed_code_unit_subsequence;
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}
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else if (unichar <= 0xffff) {
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length = 3;
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head = 0xe0;
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head = 0xf0;
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}
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else {
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buffer[0] = '\0';
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return 0;
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goto ill_formed_code_unit_subsequence;
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}
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for (count = length - 1, shift = 0; count > 0; count--, shift += 6)
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buffer[length] = '\0';
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return length + 1;
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ill_formed_code_unit_subsequence:
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buffer[0] = '\0';
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return 0;
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}
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bool
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@ -222,6 +222,8 @@ main(void)
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assert(test_utf8(0x10005d0, "א"));
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assert(test_utf8(0x110ffff, "\xf4\x8f\xbf\xbf"));
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assert(test_utf8(0x0100d800, NULL) == 0); // Unicode surrogates
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assert(test_utf8(0x0100dfff, NULL) == 0); // Unicode surrogates
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assert(test_utf8(0x1110000, NULL) == 0);
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assert(test_utf32_to_keysym('y', XKB_KEY_y));
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assert(test_utf32_to_keysym(0x20ac, XKB_KEY_EuroSign));
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// Unicode non-characters
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assert(test_utf32_to_keysym(0xd800, XKB_KEY_NoSymbol)); // Unicode surrogates
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assert(test_utf32_to_keysym(0xdfff, XKB_KEY_NoSymbol)); // Unicode surrogates
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assert(test_utf32_to_keysym(0xfdd0, XKB_KEY_NoSymbol));
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assert(test_utf32_to_keysym(0xfdef, XKB_KEY_NoSymbol));
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assert(test_utf32_to_keysym(0xfffe, XKB_KEY_NoSymbol));
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@ -170,6 +170,8 @@ test_utf32_to_utf8(void)
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check_utf32_to_utf8(0x40, 2, "\x40");
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check_utf32_to_utf8(0xA1, 3, "\xc2\xa1");
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check_utf32_to_utf8(0x2701, 4, "\xe2\x9c\x81");
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check_utf32_to_utf8(0xd800, 0, ""); // Unicode surrogates
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check_utf32_to_utf8(0xdfff, 0, ""); // Unicode surrogates
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check_utf32_to_utf8(0x1f004, 5, "\xf0\x9f\x80\x84");
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check_utf32_to_utf8(0x110000, 0, "");
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check_utf32_to_utf8(0xffffffff, 0, "");
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