Revert "Revert "Enable verity on userdebug, and add disable-verity to adb""

This reverts commit 152d2d4234ba89e0c20c4af13e291b6049a7bc33.

Fixed build error, and also fixed memory leak spotted from warning.

(cherry-pick of bbb36319119edde9377fb80015235893c30d2bc9.)

Bug: 17691572
Change-Id: I23b5ba537f7b557432041d4338b38b9be434e981

6 files changed, 87 insertions, 29 deletions

diff --git a/fs_mgr/Android.mk b/fs_mgr/Android.mk
index 7cffc37..61bf1ee 100644
--- a/fs_mgr/Android.mk
+++ b/fs_mgr/Android.mk
@@ -13,6 +13,10 @@ LOCAL_C_INCLUDES += system/extras/ext4_utils
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
 LOCAL_CFLAGS := -Werror
 
+ifneq (,$(filter userdebug,$(TARGET_BUILD_VARIANT)))
+LOCAL_CFLAGS += -DALLOW_ADBD_DISABLE_VERITY=1
+endif
+
 include $(BUILD_STATIC_LIBRARY)
 
 
diff --git a/fs_mgr/fs_mgr.c b/fs_mgr/fs_mgr.c
index 91e6c33..40878c1 100644
--- a/fs_mgr/fs_mgr.c
+++ b/fs_mgr/fs_mgr.c
@@ -245,6 +245,16 @@ static int device_is_debuggable() {
     return strcmp(value, "1") ? 0 : 1;
 }
 
+static int device_is_secure() {
+    int ret = -1;
+    char value[PROP_VALUE_MAX];
+    ret = __system_property_get("ro.secure", value);
+    /* If error, we want to fail secure */
+    if (ret < 0)
+        return 1;
+    return strcmp(value, "0") ? 1 : 0;
+}
+
 /*
  * Tries to mount any of the consecutive fstab entries that match
  * the mountpoint of the one given by fstab->recs[start_idx].
@@ -350,9 +360,11 @@ int fs_mgr_mount_all(struct fstab *fstab)
             wait_for_file(fstab->recs[i].blk_device, WAIT_TIMEOUT);
         }
 
-        if ((fstab->recs[i].fs_mgr_flags & MF_VERIFY) &&
-            !device_is_debuggable()) {
-            if (fs_mgr_setup_verity(&fstab->recs[i]) < 0) {
+        if ((fstab->recs[i].fs_mgr_flags & MF_VERIFY) && device_is_secure()) {
+            int rc = fs_mgr_setup_verity(&fstab->recs[i]);
+            if (device_is_debuggable() && rc == FS_MGR_SETUP_VERITY_DISABLED) {
+                INFO("Verity disabled");
+            } else if (rc != FS_MGR_SETUP_VERITY_SUCCESS) {
                 ERROR("Could not set up verified partition, skipping!\n");
                 continue;
             }
@@ -467,9 +479,11 @@ int fs_mgr_do_mount(struct fstab *fstab, char *n_name, char *n_blk_device,
                      fstab->recs[i].mount_point);
         }
 
-        if ((fstab->recs[i].fs_mgr_flags & MF_VERIFY) &&
-            !device_is_debuggable()) {
-            if (fs_mgr_setup_verity(&fstab->recs[i]) < 0) {
+        if ((fstab->recs[i].fs_mgr_flags & MF_VERIFY) && device_is_secure()) {
+            int rc = fs_mgr_setup_verity(&fstab->recs[i]);
+            if (device_is_debuggable() && rc == FS_MGR_SETUP_VERITY_DISABLED) {
+                INFO("Verity disabled");
+            } else if (rc != FS_MGR_SETUP_VERITY_SUCCESS) {
                 ERROR("Could not set up verified partition, skipping!\n");
                 continue;
             }
diff --git a/fs_mgr/fs_mgr_fstab.c b/fs_mgr/fs_mgr_fstab.c
index 3f84179..ab8f128 100644
--- a/fs_mgr/fs_mgr_fstab.c
+++ b/fs_mgr/fs_mgr_fstab.c
@@ -418,6 +418,11 @@ int fs_mgr_is_nonremovable(struct fstab_rec *fstab)
     return fstab->fs_mgr_flags & MF_NONREMOVABLE;
 }
 
+int fs_mgr_is_verified(struct fstab_rec *fstab)
+{
+    return fstab->fs_mgr_flags & MF_VERIFY;
+}
+
 int fs_mgr_is_encryptable(struct fstab_rec *fstab)
 {
     return fstab->fs_mgr_flags & (MF_CRYPT | MF_FORCECRYPT);
diff --git a/fs_mgr/fs_mgr_priv_verity.h b/fs_mgr/fs_mgr_priv_verity.h
index 6193784..f90e596 100644
--- a/fs_mgr/fs_mgr_priv_verity.h
+++ b/fs_mgr/fs_mgr_priv_verity.h
@@ -14,4 +14,7 @@
  * limitations under the License.
  */
 
-int fs_mgr_setup_verity(struct fstab_rec *fstab);
\ No newline at end of file
+#define FS_MGR_SETUP_VERITY_DISABLED -2
+#define FS_MGR_SETUP_VERITY_FAIL -1
+#define FS_MGR_SETUP_VERITY_SUCCESS 0
+int fs_mgr_setup_verity(struct fstab_rec *fstab);
diff --git a/fs_mgr/fs_mgr_verity.c b/fs_mgr/fs_mgr_verity.c
index 01f7844..39f96a7 100644
--- a/fs_mgr/fs_mgr_verity.c
+++ b/fs_mgr/fs_mgr_verity.c
@@ -43,7 +43,6 @@
 #include "fs_mgr_priv_verity.h"
 
 #define VERITY_METADATA_SIZE 32768
-#define VERITY_METADATA_MAGIC_NUMBER 0xb001b001
 #define VERITY_TABLE_RSA_KEY "/verity_key"
 
 extern struct fs_info info;
@@ -157,7 +156,9 @@ static int read_verity_metadata(char *block_device, char **signature, char **tab
     uint64_t device_length;
     int protocol_version;
     FILE *device;
-    int retval = -1;
+    int retval = FS_MGR_SETUP_VERITY_FAIL;
+    *signature = 0;
+    *table = 0;
 
     device = fopen(block_device, "r");
     if (!device) {
@@ -180,8 +181,18 @@ static int read_verity_metadata(char *block_device, char **signature, char **tab
         ERROR("Couldn't read magic number!\n");
         goto out;
     }
+
+#ifdef ALLOW_ADBD_DISABLE_VERITY
+    if (magic_number == VERITY_METADATA_MAGIC_DISABLE) {
+        retval = FS_MGR_SETUP_VERITY_DISABLED;
+        INFO("Attempt to cleanly disable verity - only works in USERDEBUG");
+        goto out;
+    }
+#endif
+
     if (magic_number != VERITY_METADATA_MAGIC_NUMBER) {
-        ERROR("Couldn't find verity metadata at offset %"PRIu64"!\n", device_length);
+        ERROR("Couldn't find verity metadata at offset %"PRIu64"!\n",
+              device_length);
         goto out;
     }
 
@@ -203,14 +214,12 @@ static int read_verity_metadata(char *block_device, char **signature, char **tab
     }
     if (!fread(*signature, RSANUMBYTES, 1, device)) {
         ERROR("Couldn't read signature from verity metadata!\n");
-        free(*signature);
         goto out;
     }
 
     // get the size of the table
     if (!fread(&table_length, sizeof(int), 1, device)) {
         ERROR("Couldn't get the size of the verity table from metadata!\n");
-        free(*signature);
         goto out;
     }
 
@@ -223,16 +232,22 @@ static int read_verity_metadata(char *block_device, char **signature, char **tab
     }
     if (!fgets(*table, table_length, device)) {
         ERROR("Couldn't read the verity table from metadata!\n");
-        free(*table);
-        free(*signature);
         goto out;
     }
 
-    retval = 0;
+    retval = FS_MGR_SETUP_VERITY_SUCCESS;
 
 out:
     if (device)
         fclose(device);
+
+    if (retval != FS_MGR_SETUP_VERITY_SUCCESS) {
+        free(*table);
+        free(*signature);
+        *table = 0;
+        *signature = 0;
+    }
+
     return retval;
 }
 
@@ -360,10 +375,11 @@ static int set_verified_property(char *name) {
 int fs_mgr_setup_verity(struct fstab_rec *fstab) {
 
     int retval = -1;
+    int fd = -1;
 
-    char *verity_blk_name;
-    char *verity_table;
-    char *verity_table_signature;
+    char *verity_blk_name = 0;
+    char *verity_table = 0;
+    char *verity_table_signature = 0;
 
     char buffer[DM_BUF_SIZE];
     struct dm_ioctl *io = (struct dm_ioctl *) buffer;
@@ -380,11 +396,19 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab) {
         return retval;
     }
 
+    // read the verity block at the end of the block device
+    // send error code up the chain so we can detect attempts to disable verity
+    retval = read_verity_metadata(fstab->blk_device,
+                                  &verity_table_signature,
+                                  &verity_table);
+    if (retval < 0) {
+        goto out;
+    }
+
     // get the device mapper fd
-    int fd;
     if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) {
         ERROR("Error opening device mapper (%s)", strerror(errno));
-        return retval;
+        goto out;;
     }
 
     // create the device
@@ -399,14 +423,6 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab) {
         goto out;
     }
 
-    verity_table = verity_table_signature = NULL;
-    // read the verity block at the end of the block device
-    if (read_verity_metadata(fstab->blk_device,
-                                    &verity_table_signature,
-                                    &verity_table) < 0) {
-        goto out;
-    }
-
     // verify the signature on the table
     if (verify_table(verity_table_signature,
                             verity_table,
@@ -427,6 +443,7 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab) {
     // assign the new verity block device as the block device
     free(fstab->blk_device);
     fstab->blk_device = verity_blk_name;
+    verity_blk_name = 0;
 
     // make sure we've set everything up properly
     if (test_access(fstab->blk_device) < 0) {
@@ -437,6 +454,13 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab) {
     retval = set_verified_property(mount_point);
 
 out:
-    close(fd);
+    if (fd != -1) {
+        close(fd);
+    }
+
+    free (verity_table);
+    free (verity_table_signature);
+    free (verity_blk_name);
+
     return retval;
 }
diff --git a/fs_mgr/include/fs_mgr.h b/fs_mgr/include/fs_mgr.h
index 0c7eb20..5e2ff41 100644
--- a/fs_mgr/include/fs_mgr.h
+++ b/fs_mgr/include/fs_mgr.h
@@ -20,6 +20,13 @@
 #include <stdint.h>
 #include <linux/dm-ioctl.h>
 
+// Magic number at start of verity metadata
+#define VERITY_METADATA_MAGIC_NUMBER 0xb001b001
+
+// Replacement magic number at start of verity metadata to cleanly
+// turn verity off in userdebug builds.
+#define VERITY_METADATA_MAGIC_DISABLE 0x46464f56 // "VOFF"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -74,6 +81,7 @@ int fs_mgr_add_entry(struct fstab *fstab,
 struct fstab_rec *fs_mgr_get_entry_for_mount_point(struct fstab *fstab, const char *path);
 int fs_mgr_is_voldmanaged(struct fstab_rec *fstab);
 int fs_mgr_is_nonremovable(struct fstab_rec *fstab);
+int fs_mgr_is_verified(struct fstab_rec *fstab);
 int fs_mgr_is_encryptable(struct fstab_rec *fstab);
 int fs_mgr_is_noemulatedsd(struct fstab_rec *fstab);
 int fs_mgr_swapon_all(struct fstab *fstab);