Fix shadow cache path resolution with host_root#42
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ensure_path_shadow_cache and reopen_cached_shadow_fd called open() on guest-relative paths (host_root prefix already stripped by kbox_translate_path_for_lkl), resolving against the supervisor's real root instead of host_root. Read-only sandbox escape when host_root is set: guest opens /etc/passwd, supervisor opens the host's /etc/passwd rather than host_root/etc/passwd. Add build_host_open_path() that re-prefixes ctx->host_root before open(). In pure image mode (no host_root) the helper is a passthrough. Change-Id: I9957ce0127bc733b1013fe2ee04e0654635d8ba9
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ensure_path_shadow_cache and reopen_cached_shadow_fd called open() on guest-relative paths (host_root prefix already stripped by kbox_translate_path_for_lkl), resolving against the supervisor's real root instead of host_root. Read-only sandbox escape when host_root is set: guest opens /etc/passwd, supervisor opens the host's /etc/passwd rather than host_root/etc/passwd.
Add build_host_open_path() that re-prefixes ctx->host_root before open(). In pure image mode (no host_root) the helper is a passthrough.
Change-Id: I9957ce0127bc733b1013fe2ee04e0654635d8ba9
Summary by cubic
Fixes path resolution when
host_rootis set so shadow cache opens files underhost_rootinstead of the supervisor’s real root. Prevents a read-only sandbox escape (e.g.,/etc/passwdresolving to the host).build_host_open_path()to prefixctx->host_rootbeforeopen().ensure_path_shadow_cacheandreopen_cached_shadow_fdto use it; passthrough when nohost_root.Written for commit 0000933. Summary will update on new commits.