commit ee19387905650cab5da7dd97ada5502cd17ac93d
author Andres Morales <anmorales@google.com> Tue Aug 05 19:49:09 2014 -0700
committer Andres Morales <anmorales@google.com> Wed Aug 06 09:58:55 2014 -0700
tree 46f1c336bce478470cf2b45511f7a55c61db5021
parent a91ecc59b2753a3dcc93b2619559a980074e77bd

Erase PST partition if its marked to be erased.

We need to wipe the challenges on this partition
if OEM unlock is enabled, as this is a signal that
the user has opted out of factory reset protection.

go/factory-reset

Bug: 16633064
Change-Id: Icb8f1433bf99ca57813f5b72d5a3dd15fa94a263

recovery.cpp

diff --git a/recovery.cpp b/recovery.cpp
index d2d85e7..f78d6e4 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -659,6 +659,7 @@
     device->WipeData();
     erase_volume("/data");
     erase_volume("/cache");
+    erase_persistent_partition();
     ui->Print("Data wipe complete.\n");
 }
 
@@ -959,6 +960,7 @@
         if (device->WipeData()) status = INSTALL_ERROR;
         if (erase_volume("/data")) status = INSTALL_ERROR;
         if (wipe_cache && erase_volume("/cache")) status = INSTALL_ERROR;
+        if (erase_persistent_partition() == -1 ) status = INSTALL_ERROR;
         if (status != INSTALL_SUCCESS) ui->Print("Data wipe failed.\n");
     } else if (wipe_cache) {
         if (wipe_cache && erase_volume("/cache")) status = INSTALL_ERROR;

roots.cpp

diff --git a/roots.cpp b/roots.cpp
index 8f99019..61798f4 100644
--- a/roots.cpp
+++ b/roots.cpp
@@ -39,6 +39,8 @@
 
 extern struct selabel_handle *sehandle;
 
+static const char* PERSISTENT_PATH = "/persistent";
+
 void load_volume_table()
 {
     int i;
@@ -264,6 +266,41 @@
     return -1;
 }
 
+int erase_persistent_partition() {
+    Volume *v = volume_for_path(PERSISTENT_PATH);
+    if (v == NULL) {
+        // most devices won't have /persistent, so this is not an error.
+        return 0;
+    }
+
+    int fd = open(v->blk_device, O_RDWR);
+    uint64_t size = get_file_size(fd);
+    if (size == 0) {
+        LOGE("failed to stat size of /persistent\n");
+        close(fd);
+        return -1;
+    }
+
+    char oem_unlock_enabled;
+    lseek(fd, size - 1, SEEK_SET);
+    read(fd, &oem_unlock_enabled, 1);
+
+    if (oem_unlock_enabled) {
+        if (wipe_block_device(fd, size)) {
+           LOGE("error wiping /persistent: %s\n", strerror(errno));
+           close(fd);
+           return -1;
+        }
+
+        lseek(fd, size - 1, SEEK_SET);
+        write(fd, &oem_unlock_enabled, 1);
+    }
+
+    close(fd);
+
+    return (int) oem_unlock_enabled;
+}
+
 int setup_install_mounts() {
     if (fstab == NULL) {
         LOGE("can't set up install mounts: no fstab loaded\n");

roots.h

diff --git a/roots.h b/roots.h
index 230d9de..b62a5b1 100644
--- a/roots.h
+++ b/roots.h
@@ -46,6 +46,11 @@
 // mounted (/tmp and /cache) are mounted.  Returns 0 on success.
 int setup_install_mounts();
 
+// Conditionally wipes the /persistent partition if it's marked
+// to wipe. Returns -1 on failure, 1 if the partition was wiped
+// and 0 if the partition was not wiped.
+int erase_persistent_partition();
+
 #ifdef __cplusplus
 }
 #endif