From 45fdf8579083dac618d57150429cc1d1149cd2b9 Mon Sep 17 00:00:00 2001
From: Janik Besendorf <janik@besendorf.org>
Date: Sat, 22 Aug 2026 14:16:24 +0200
Subject: [PATCH] Add bugreport mountinfo parser

---
 src/mvt/android/artifacts/mounts.py         | 45 +++++++++++++++++++++
 src/mvt/android/modules/bugreport/mounts.py | 41 +++++++++++++++++++
 tests/android_androidqf/test_mounts.py      | 13 ++++++
 3 files changed, 99 insertions(+)
 create mode 100644 src/mvt/android/modules/bugreport/mounts.py

diff --git a/src/mvt/android/artifacts/mounts.py b/src/mvt/android/artifacts/mounts.py
index a35d889..5a5537b 100644
--- a/src/mvt/android/artifacts/mounts.py
+++ b/src/mvt/android/artifacts/mounts.py
@@ -117,6 +117,51 @@ class Mounts(AndroidArtifact):
                 # Skip lines that don't match expected format
                 continue
 
+    @staticmethod
+    def parse_mountinfo(entry: str, process_id: int) -> list[dict[str, Any]]:
+        """Parse Linux /proc/PID/mountinfo records."""
+        results = []
+        for line in entry.splitlines():
+            fields = line.split()
+            if "-" not in fields:
+                continue
+            separator = fields.index("-")
+            if separator < 6 or len(fields) < separator + 4:
+                continue
+            try:
+                mount_id = int(fields[0])
+                parent_id = int(fields[1])
+            except ValueError:
+                continue
+            mount_options = fields[5].split(",")
+            super_options = fields[separator + 3].split(",")
+            options = list(dict.fromkeys(mount_options + super_options))
+            mount_point = fields[4].replace("\\040", " ")
+            device = fields[separator + 2].replace("\\040", " ")
+            filesystem_type = fields[separator + 1]
+            is_system = mount_point in SUSPICIOUS_MOUNT_POINTS or any(
+                mount_point.startswith(f"{prefix}/")
+                for prefix in SUSPICIOUS_MOUNT_POINTS
+            )
+            results.append(
+                {
+                    "mount_id": mount_id,
+                    "parent_id": parent_id,
+                    "major_minor": fields[2],
+                    "root": fields[3].replace("\\040", " "),
+                    "mount_point": mount_point,
+                    "device": device,
+                    "filesystem_type": filesystem_type,
+                    "mount_options": ",".join(options),
+                    "options_list": options,
+                    "optional_fields": fields[6:separator],
+                    "is_system_partition": is_system,
+                    "is_read_write": "rw" in options,
+                    "process_ids": [process_id],
+                }
+            )
+        return results
+
     def check_indicators(self) -> None:
         """
         Check for suspicious mount configurations that may indicate root access
diff --git a/src/mvt/android/modules/bugreport/mounts.py b/src/mvt/android/modules/bugreport/mounts.py
new file mode 100644
index 0000000..ecef40c
--- /dev/null
+++ b/src/mvt/android/modules/bugreport/mounts.py
@@ -0,0 +1,41 @@
+# Mobile Verification Toolkit (MVT)
+# Copyright (c) 2021-2026 The MVT Authors.
+
+import re
+
+from mvt.android.artifacts.mounts import Mounts as MountsArtifact
+
+from .base import BugReportModule
+
+
+class Mounts(MountsArtifact, BugReportModule):
+    """Extract and deduplicate process mount namespaces from mountinfo."""
+
+    def run(self) -> None:
+        mount_files = self._get_files_by_pattern("FS/proc/*/mountinfo")
+        if not mount_files:
+            mount_files = self._get_files_by_pattern("*/proc/*/mountinfo")
+        unique: dict[tuple, dict] = {}
+        for file_path in mount_files:
+            pid_match = re.search(r"/proc/(\d+)/mountinfo$", file_path)
+            if not pid_match:
+                continue
+            entries = self.parse_mountinfo(
+                self._get_file_content(file_path).decode("utf-8", errors="replace"),
+                int(pid_match.group(1)),
+            )
+            for entry in entries:
+                identity = (
+                    entry["major_minor"],
+                    entry["root"],
+                    entry["mount_point"],
+                    entry["device"],
+                    entry["filesystem_type"],
+                    entry["mount_options"],
+                )
+                if identity in unique:
+                    unique[identity]["process_ids"].extend(entry["process_ids"])
+                else:
+                    unique[identity] = entry
+        self.results = list(unique.values())
+        self.log.info("Extracted %d unique mount records", len(self.results))
diff --git a/tests/android_androidqf/test_mounts.py b/tests/android_androidqf/test_mounts.py
index d66925d..5f47176 100644
--- a/tests/android_androidqf/test_mounts.py
+++ b/tests/android_androidqf/test_mounts.py
@@ -13,6 +13,19 @@ from ..utils import get_android_androidqf, list_files
 
 
 class TestAndroidqfMountsArtifact:
+    def test_parse_proc_mountinfo(self):
+        from mvt.android.artifacts.mounts import Mounts as MountsArtifact
+
+        results = MountsArtifact.parse_mountinfo(
+            "41 40 254:13 / / ro,relatime shared:1 - erofs /dev/block/dm-13 ro,seclabel\n",
+            123,
+        )
+
+        assert results[0]["mount_id"] == 41
+        assert results[0]["mount_point"] == "/"
+        assert results[0]["filesystem_type"] == "erofs"
+        assert results[0]["process_ids"] == [123]
+
     def test_parse_mounts_token_checks(self):
         """
         Test the artifact-level `parse` method using tolerant token checks.