From d037ca1b7b09fb2a892bbf0011fe7e34956275ff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Francisco=20Jos=C3=A9=20Garc=C3=ADa=20Garc=C3=ADa?=
 <frangarcj@gmail.com>
Date: Tue, 20 Oct 2026 17:43:14 +0200
Subject: [PATCH] PBPReader: Read part of a subfile

GetSubFile() reads a whole subfile, and refuses those over 256MB.
ReadSubFile() reads a range of one, for the PSAR of a PS1 EBOOT, which holds
its disc image.
---
 Core/ELF/PBPReader.cpp | 11 +++++++++++
 Core/ELF/PBPReader.h   |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/Core/ELF/PBPReader.cpp b/Core/ELF/PBPReader.cpp
index 96f9819352..cdcb9c963f 100644
--- a/Core/ELF/PBPReader.cpp
+++ b/Core/ELF/PBPReader.cpp
@@ -79,6 +79,17 @@ bool PBPReader::GetSubFile(PBPSubFile file, std::vector<u8> *out) const {
 	return true;
 }
 
+bool PBPReader::ReadSubFile(PBPSubFile file, u32 offset, size_t size, void *out) const {
+	if (!file_) {
+		return false;
+	}
+	const size_t subFileSize = GetSubFileSize(file);
+	if (offset > subFileSize || size > subFileSize - offset) {
+		return false;
+	}
+	return file_->ReadAt(header_.offsets[(int)file] + offset, size, out) == size;
+}
+
 bool PBPReader::GetSubFileAsString(PBPSubFile file, std::string *out) const {
 	if (!file_) {
 		out->clear();
diff --git a/Core/ELF/PBPReader.h b/Core/ELF/PBPReader.h
index 8781aa66a7..b11ff11baa 100644
--- a/Core/ELF/PBPReader.h
+++ b/Core/ELF/PBPReader.h
@@ -53,6 +53,8 @@ public:
 
 	bool GetSubFile(PBPSubFile file, std::vector<u8> *out) const;
 	bool GetSubFileAsString(PBPSubFile file, std::string *out) const;
+	// Part of a subfile, for the large ones. False if it doesn't lie within it.
+	bool ReadSubFile(PBPSubFile file, u32 offset, size_t size, void *out) const;
 
 	size_t GetSubFileSize(PBPSubFile file) const {
 		const int num = (int)file;