commit dfd2478bd172c3e6242cee5e0a7dcea2c4ee3056
author Jeremy Compostella <jeremy.compostella@intel.com> Tue Apr 26 13:51:27 2016 +0200
committer Badhri Jagan Sridharan <badhri@google.com> Mon May 16 16:37:24 2016 +0000
tree 24ac01e8dff88e2f190f241a122a02c171ea0791
parent faa14b94d5a6d0c3d429516bf226b9836f65da91

fs_mgr: update block device reference in verity metadata

The dm-verity metadata contains the block device path that is given to
the dm-android-verity driver.  If the device is using slot A/B, this
path is missing the slot suffix.

This patch makes fs_mgr replace all the block device path reference
with the one including the active slot suffix.

Change-Id: Ib624d0d18b12a8a287cac7f15605a2e0fb7c97c6
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>

fs_mgr/fs_mgr_verity.cpp

diff --git a/fs_mgr/fs_mgr_verity.cpp b/fs_mgr/fs_mgr_verity.cpp
index 129a5bb..72554a8 100644
--- a/fs_mgr/fs_mgr_verity.cpp
+++ b/fs_mgr/fs_mgr_verity.cpp
@@ -30,6 +30,7 @@
 #include <unistd.h>
 
 #include <android-base/file.h>
+#include <android-base/strings.h>
 #include <crypto_utils/android_pubkey.h>
 #include <cutils/properties.h>
 #include <logwrap/logwrap.h>
@@ -211,7 +212,7 @@
 }
 
 struct verity_table_params {
-    const char *table;
+    char *table;
     int mode;
     struct fec_ecc_metadata ecc;
     const char *ecc_dev;
@@ -843,15 +844,42 @@
     return rc;
 }
 
+static void update_verity_table_blk_device(char *blk_device, char **table)
+{
+    std::string result, word;
+    auto tokens = android::base::Split(*table, " ");
+
+    for (const auto token : tokens) {
+        if (android::base::StartsWith(token, "/dev/block/") &&
+            android::base::StartsWith(blk_device, token.c_str())) {
+            word = blk_device;
+        } else {
+            word = token;
+        }
+
+        if (result.empty()) {
+            result = word;
+        } else {
+            result += " " + word;
+        }
+    }
+
+    if (result.empty()) {
+        return;
+    }
+
+    free(*table);
+    *table = strdup(result.c_str());
+}
+
 int fs_mgr_setup_verity(struct fstab_rec *fstab)
 {
     int retval = FS_MGR_SETUP_VERITY_FAIL;
     int fd = -1;
-    char *invalid_table = NULL;
     char *verity_blk_name = NULL;
     struct fec_handle *f = NULL;
     struct fec_verity_metadata verity;
-    struct verity_table_params params;
+    struct verity_table_params params = { .table = NULL };
 
     alignas(dm_ioctl) char buffer[DM_BUF_SIZE];
     struct dm_ioctl *io = (struct dm_ioctl *) buffer;
@@ -912,8 +940,17 @@
         params.mode = VERITY_MODE_EIO;
     }
 
+    if (!verity.table) {
+        goto out;
+    }
+
+    params.table = strdup(verity.table);
+    if (!params.table) {
+        goto out;
+    }
+
     // verify the signature on the table
-    if (verify_table(verity.signature, sizeof(verity.signature), verity.table,
+    if (verify_table(verity.signature, sizeof(verity.signature), params.table,
             verity.table_length) < 0) {
         if (params.mode == VERITY_MODE_LOGGING) {
             // the user has been warned, allow mounting without dm-verity
@@ -922,20 +959,18 @@
         }
 
         // invalidate root hash and salt to trigger device-specific recovery
-        invalid_table = strdup(verity.table);
-
-        if (!invalid_table ||
-                invalidate_table(invalid_table, verity.table_length) < 0) {
+        if (invalidate_table(params.table, verity.table_length) < 0) {
             goto out;
         }
-
-        params.table = invalid_table;
-    } else {
-        params.table = verity.table;
     }
 
     INFO("Enabling dm-verity for %s (mode %d)\n", mount_point, params.mode);
 
+    if (fstab->fs_mgr_flags & MF_SLOTSELECT) {
+        // Update the verity params using the actual block device path
+        update_verity_table_blk_device(fstab->blk_device, &params.table);
+    }
+
     // load the verity mapping table
     if (load_verity_table(io, mount_point, verity.data_size, fd, &params,
             format_verity_table) == 0) {
@@ -1001,7 +1036,7 @@
     }
 
     fec_close(f);
-    free(invalid_table);
+    free(params.table);
     free(verity_blk_name);
 
     return retval;