Auto merge of #16063 - methyl:image-usemap-panics, r=nox

Avoid panics for empty or multibyte image usemap

<!-- Please describe your changes on the following line: -->
Some check were added to make sure we can call `split_at` with no risk of panics (when value is empty or the first char is multibyte).

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #15883 (github issue number if applicable).
- [x] There are tests for these changes

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This commit is contained in:
bors-servo 2017-04-12 07:34:27 -05:00 committed by GitHub
commit 69eda6a60c
3 changed files with 33 additions and 0 deletions

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@ -423,6 +423,11 @@ impl HTMLImageElement {
};
let value = usemap_attr.value();
if value.len() == 0 || !value.is_char_boundary(1) {
return None
}
let (first, last) = value.split_at(1);
if first != "#" || last.len() == 0 {

View file

@ -12952,6 +12952,12 @@
{}
]
],
"mozilla/htmlimageelement.html": [
[
"/_mozilla/mozilla/htmlimageelement.html",
{}
]
],
"mozilla/htmllabel-activation.html": [
[
"/_mozilla/mozilla/htmllabel-activation.html",
@ -25499,6 +25505,10 @@
"54fe6bbc1a7a35ceb14a3bf33f81ebed55beaf72",
"testharness"
],
"mozilla/htmlimageelement.html": [
"f1857a8f413f444b34464f0a3bc6b46af13c1a5a",
"testharness"
],
"mozilla/htmllabel-activation.html": [
"2013b49684d0b861415a2e766d5d260906b1f3fb",
"testharness"

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@ -0,0 +1,18 @@
<!doctype html>
<meta charset="utf-8">
<title>HTMLImageElement usemap special cases</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<img id="empty" usemap>
<img id="multibyte" usemap=&#x1F4A9;>
<script>
test(function () {
document.querySelector("#empty").dispatchEvent(new Event("click"));
assert_true(true);
}, "Do not panic on empty usemap");
test(function () {
document.querySelector("#multibyte").dispatchEvent(new Event("click"));
assert_true(true);
}, "Do not panic on multibyte usemap");
</script>