udf: Check output buffer length when converting name to CS0 (bb00c898) · Commits · 戴 / test

If a name contains at least some characters with Unicode values exceeding single byte, the CS0 output should have 2 bytes per character. And if other input characters have single byte Unicode values, then the single input byte is converted to 2 output bytes, and the length of output becomes larger than the length of input. And if the input name is long enough, the output length may exceed the allocated buffer length. All this means that conversion from UTF8 or NLS to CS0 requires checking of output length in order to stop when it exceeds the given output buffer size. [JK: Make code return -ENAMETOOLONG instead of silently truncating the name] CC: stable@vger.kernel.org Signed-off-by:

Andrew Gabbasov <andrew_gabbasov@mentor.com> Signed-off-by:

Jan Kara <jack@suse.cz>

fs/udf/unicode.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -177,17 +177,22 @@ int udf_CS0toUTF8(struct ustr utf_o, const struct ustr ocu_i)
		static int udf_UTF8toCS0(dstring ocu, struct ustr utf, int length)
		{
		unsigned c, i, max_val, utf_char;
		int utf_cnt, u_len;
		int utf_cnt, u_len, u_ch;

		memset(ocu, 0, sizeof(dstring) * length);
		ocu[0] = 8;
		max_val = 0xffU;
		u_ch = 1;

		try_again:
		u_len = 0U;
		utf_char = 0U;
		utf_cnt = 0U;
		for (i = 0U; i < utf->u_len; i++) {
		/* Name didn't fit? */
		if (u_len + 1 + u_ch >= length)
		return 0;

		c = (uint8_t)utf->u_name[i];

		/* Complete a multi-byte UTF-8 character */
		@@ -229,6 +234,7 @@ try_again:
		if (max_val == 0xffU) {
		max_val = 0xffffU;
		ocu[0] = (uint8_t)0x10U;
		u_ch = 2;
		goto try_again;
		}
		goto error_out;
		@@ -299,15 +305,19 @@ static int udf_NLStoCS0(struct nls_table nls, dstring ocu, struct ustr *uni,
		int len;
		unsigned i, max_val;
		uint16_t uni_char;
		int u_len;
		int u_len, u_ch;

		memset(ocu, 0, sizeof(dstring) * length);
		ocu[0] = 8;
		max_val = 0xffU;
		u_ch = 1;

		try_again:
		u_len = 0U;
		for (i = 0U; i < uni->u_len; i++) {
		/* Name didn't fit? */
		if (u_len + 1 + u_ch >= length)
		return 0;
		len = nls->char2uni(&uni->u_name[i], uni->u_len - i, &uni_char);
		if (!len)
		continue;
		@@ -320,6 +330,7 @@ try_again:
		if (uni_char > max_val) {
		max_val = 0xffffU;
		ocu[0] = (uint8_t)0x10U;
		u_ch = 2;
		goto try_again;
		}

Admin message