Fix memory overwrites in SystemNative_GetNetworkInterfaces

[gwr]

Not only Android might see count = ip4count + ip6count, which would lead to overwriting the NetworkInterfaceInfo this is meant to return.

Something I discovered while working on #124728

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[Copilot]

Pull request overview

This PR fixes a potential buffer overlap in SystemNative_GetNetworkInterfaces by ensuring the native allocation always reserves space for both the returned NetworkInterfaceInfo array and the IpAddressInfo array, even when getifaddrs returns only IPv4/IPv6 entries (so count == ip4count + ip6count).

Changes:

• Make the allocation size always account for count + ip4count + ip6count entries to prevent overwriting the interface array.
• Set addressList to start immediately after NetworkInterfaceInfo[count] (instead of a computed offset that can become 0).
• Remove the Android-only conditional sizing logic and replace it with a platform-agnostic approach.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/native/libs/System.Native/pal_interfaceaddresses.c:365

• On allocation failure, the getifaddrs() result in head is not freed before returning. This leaks the ifaddrs list in the OOM path; please call freeifaddrs(head) before setting errno/returning (and keep head valid for that call).

 void * memoryBlock = calloc((size_t)entriesCount, sizeof(NetworkInterfaceInfo));
if (memoryBlock == NULL)
{
errno = ENOMEM;
return -1;
}

[gwr]

Fixed the assert, squash.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

[gwr]

An earlier version didn't build. Someone please "kick" the CI stuff to run again.

[wfurt]

LGTH. Thanks @gwr for the contribution.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

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