Ref and rootfs helpers may read paths supplied by frontends or build outputs.
Reject non-regular files before reading them into memory so device and FIFO
paths cannot feed no-EOF streams into parsers or bundle injection logic.
Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
Add a build request option that rewrites default exec networking to an
internal proxy network while preserving explicit none networking.
Route HTTP and HTTPS traffic through a BuildKit-owned proxy namespace, enforce
source policy checks for proxied requests, and inject a temporary CA into Linux
rootfs trust bundles for HTTPS interception.
Share namespace pooling between CNI and proxy providers, and cover proxy mode
with unit and integration tests.
Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>