…tion surface. (flutter/engine#56928)

…159842)

flutter/engine@05e2d65...b4f52b2

2024-12-05 [email protected] Drop APNG frames that don't fit entirely
within the destination surface. (flutter/engine#56928)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
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Please CC [email protected],[email protected] on the revert to ensure that a
human
is aware of the problem.

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…ce. (flutter#56928)

As per the [spec](https://www.w3.org/TR/png/#fcTL-chunk):

> The frame must be rendered within the region defined by x_offset, y_offset, width, and height. This region may not fall outside of the default image; thus x_offset plus width must not be greater than the [IHDR](https://www.w3.org/TR/png/#11IHDR) width; similarly y_offset plus height must not be greater than the [IHDR](https://www.w3.org/TR/png/#11IHDR) height.

The `offset + bounds` calculation in the bounds checks could wrap around, bypassing the check.

(Follow up to #56928)

…ce. (flutter#56928)

As per the [spec](https://www.w3.org/TR/png/#fcTL-chunk):

> The frame must be rendered within the region defined by x_offset, y_offset, width, and height. This region may not fall outside of the default image; thus x_offset plus width must not be greater than the [IHDR](https://www.w3.org/TR/png/#11IHDR) width; similarly y_offset plus height must not be greater than the [IHDR](https://www.w3.org/TR/png/#11IHDR) height.

…#57025)

The `offset + bounds` calculation in the bounds checks could wrap around, bypassing the check.

(Follow up to flutter#56928)

…tion surface. (#57062)

This cherry-pick PR includes:

#56928 followed by #57025

It supersedes #56978.

### Issue Link:
What is the link to the issue this cherry-pick is addressing?

Issue was reported over email.

### Changelog Description:
Explain this cherry pick in one line that is accessible to most Flutter developers. See [best practices](https://github.com/flutter/flutter/blob/main/docs/releases/Hotfix-Documentation-Best-Practices.md) for examples

Fixes an out-of-bounds memory write in APNG decoding.

### Impact Description:
What is the impact (ex. visual jank on Samsung phones, app crash, cannot ship an iOS app)? Does it impact development (ex. flutter doctor crashes when Android Studio is installed), or the shipping production app (the app crashes on launch)

Fixes an issue in which an untrusted malformed APNG image could cause out of bounds memory writes, crashing the app.

### Workaround:
Is there a workaround for this issue?

There is no workaround.

### Risk:
What is the risk level of this cherry-pick?

### Test Coverage:
Are you confident that your fix is well-tested by automated tests?

### Validation Steps:
What are the steps to validate that this fix works?

Attempt to load the APNG used in the tests in the PR.

…ce. (flutter/engine#56928)

As per the [spec](https://www.w3.org/TR/png/#fcTL-chunk):

> The frame must be rendered within the region defined by x_offset, y_offset, width, and height. This region may not fall outside of the default image; thus x_offset plus width must not be greater than the [IHDR](https://www.w3.org/TR/png/#11IHDR) width; similarly y_offset plus height must not be greater than the [IHDR](https://www.w3.org/TR/png/#11IHDR) height.

…/engine#57025)

The `offset + bounds` calculation in the bounds checks could wrap around, bypassing the check.

(Follow up to flutter/engine#56928)