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xml BUGFIX reject character references that overflow #2623

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Merged
michalvasko merged 1 commit into from
Nov 9, 2026
Merged

xml BUGFIX reject character references that overflow #2623

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10 changes: 10 additions & 0 deletions src/xml.c
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Original file line number Diff line number Diff line change
Expand Up @@ -516,10 +516,20 @@ lyxml_parse_value(struct lyxml_ctx *xmlctx, char endchar, char **value, uint32_t
ADD_CHECK_OVERFLOW(offset, 1, error);
if (isdigit(in[offset])) {
for (n = 0; isdigit(in[offset]); offset++) {
if (n > 0x10ffff) {
/* too large, would overflow */
LOGVAL(ctx, NULL, LYVE_SYNTAX, "Invalid character reference \"%.12s\".", p);
goto error;
}
n = (LY_BASE_DEC * n) + (in[offset] - '0');
}
} else if ((in[offset] == 'x') && isxdigit(in[offset + 1])) {
for (n = 0, ++offset; isxdigit(in[offset]); offset++) {
if (n > 0x10ffff) {
/* too large, would overflow */
LOGVAL(ctx, NULL, LYVE_SYNTAX, "Invalid character reference \"%.12s\".", p);
goto error;
}
if (isdigit(in[offset])) {
u = (in[offset] - '0');
} else if (in[offset] > 'F') {
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16 changes: 16 additions & 0 deletions tests/utests/basic/test_xml.c
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Expand Up @@ -268,6 +268,22 @@ test_text(void **state)
str = "<e xmlns=\"urn:test\" attr=\'&#xffff;\'";
assert_int_equal(LY_EVALID, lyd_parse_data_mem(ctx, str, LYD_XML, 0, LYD_VALIDATE_PRESENT, &tree));
CHECK_LOG_CTX("Invalid character reference \"&#xffff;\'\" (0x0000ffff).", NULL, 1);

/* character references too large to fit, must not wrap around to "<" */
str = "<e xmlns=\"urn:test\" attr=\'&#4294967356;\'";
assert_int_equal(LY_EVALID, lyd_parse_data_mem(ctx, str, LYD_XML, 0, LYD_VALIDATE_PRESENT, &tree));
CHECK_LOG_CTX("Invalid character reference \"&#4294967356\".", NULL, 1);

str = "<e xmlns=\"urn:test\">&#x10000003C;</e>";
assert_int_equal(LY_EVALID, lyd_parse_data_mem(ctx, str, LYD_XML, 0, LYD_VALIDATE_PRESENT, &tree));
CHECK_LOG_CTX("Invalid character reference \"&#x10000003C\".", NULL, 1);

/* leading zeros are fine */
str = "<e xmlns=\"urn:test\">&#00000000000000000060;&#x0000000000003C;</e>";
assert_int_equal(LY_SUCCESS, lyd_parse_data_mem(ctx, str, LYD_XML, 0, LYD_VALIDATE_PRESENT, &tree));
assert_non_null(tree);
lyd_free_all(tree);
tree = NULL;
}

static void
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