1 files changed, 46 insertions, 21 deletions

diff --git a/fs_mgr/fs_mgr_verity.c b/fs_mgr/fs_mgr_verity.c
index b79a4a8..bcd9094 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;
@@ -155,7 +154,9 @@ 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) {
@@ -178,8 +179,18 @@ 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;
     }
 
@@ -201,14 +212,12 @@ 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;
     }
 
@@ -221,16 +230,22 @@ 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;
 }
 
@@ -358,10 +373,11 @@ 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;
@@ -378,11 +394,19 @@ 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
@@ -397,13 +421,6 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab) {
         goto out;
     }
 
-    // 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,
@@ -424,6 +441,7 @@ 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) {
@@ -434,6 +452,13 @@ 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;
 }