libdm: Add DmTargetVerity and use it in fs_mgr_avb.
This change adds a DmTargetVerity class and replaces the existing verity
table builder in fs_mgr_avb.cpp. DmTargetVerity must be constructed with
all the required parameters for dm-verity. Additional arguments can be
appended via helper methods.
Bug: 110035986
Test: libdm_test gtest; boots with verity on AVB devices
Change-Id: I4fc2f7ef122c841e8b4ec4156177a6224ffbac30
diff --git a/fs_mgr/fs_mgr_avb.cpp b/fs_mgr/fs_mgr_avb.cpp
index 2020fa6..7c6093e 100644
--- a/fs_mgr/fs_mgr_avb.cpp
+++ b/fs_mgr/fs_mgr_avb.cpp
@@ -33,11 +33,11 @@
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <libavb/libavb.h>
+#include <libdm/dm.h>
#include "fs_mgr.h"
#include "fs_mgr_priv.h"
#include "fs_mgr_priv_avb_ops.h"
-#include "fs_mgr_priv_dm_ioctl.h"
#include "fs_mgr_priv_sha.h"
static inline bool nibble_value(const char& c, uint8_t* value) {
@@ -218,9 +218,9 @@
// Constructs dm-verity arguments for sending DM_TABLE_LOAD ioctl to kernel.
// See the following link for more details:
// https://gitlab.com/cryptsetup/cryptsetup/wikis/DMVerity
-static std::string construct_verity_table(const AvbHashtreeDescriptor& hashtree_desc,
- const std::string& salt, const std::string& root_digest,
- const std::string& blk_device) {
+static bool construct_verity_table(const AvbHashtreeDescriptor& hashtree_desc,
+ const std::string& salt, const std::string& root_digest,
+ const std::string& blk_device, android::dm::DmTable* table) {
// Loads androidboot.veritymode from kernel cmdline.
std::string verity_mode;
if (!fs_mgr_get_boot_config("veritymode", &verity_mode)) {
@@ -235,145 +235,56 @@
dm_verity_mode = "ignore_corruption";
} else if (verity_mode != "eio") { // Default dm_verity_mode is eio.
LERROR << "Unknown androidboot.veritymode: " << verity_mode;
- return "";
+ return false;
}
- // dm-verity construction parameters:
- // <version> <dev> <hash_dev>
- // <data_block_size> <hash_block_size>
- // <num_data_blocks> <hash_start_block>
- // <algorithm> <digest> <salt>
- // [<#opt_params> <opt_params>]
- std::ostringstream verity_table;
- verity_table << hashtree_desc.dm_verity_version << " " << blk_device << " " << blk_device << " "
- << hashtree_desc.data_block_size << " " << hashtree_desc.hash_block_size << " "
- << hashtree_desc.image_size / hashtree_desc.data_block_size << " "
- << hashtree_desc.tree_offset / hashtree_desc.hash_block_size << " "
- << hashtree_desc.hash_algorithm << " " << root_digest << " " << salt;
+ std::ostringstream hash_algorithm;
+ hash_algorithm << hashtree_desc.hash_algorithm;
- // Continued from the above optional parameters:
- // [<#opt_params> <opt_params>]
- int optional_argc = 0;
- std::ostringstream optional_args;
-
- // dm-verity optional parameters for FEC (forward error correction):
- // use_fec_from_device <fec_dev>
- // fec_roots <num>
- // fec_blocks <num>
- // fec_start <offset>
+ android::dm::DmTargetVerity target(0, hashtree_desc.image_size / 512,
+ hashtree_desc.dm_verity_version, blk_device, blk_device,
+ hashtree_desc.data_block_size, hashtree_desc.hash_block_size,
+ hashtree_desc.image_size / hashtree_desc.data_block_size,
+ hashtree_desc.tree_offset / hashtree_desc.hash_block_size,
+ hash_algorithm.str(), root_digest, salt);
if (hashtree_desc.fec_size > 0) {
- // Note that fec_blocks is the size that FEC covers, *NOT* the
- // size of the FEC data. Since we use FEC for everything up until
- // the FEC data, it's the same as the offset (fec_start).
- optional_argc += 8;
- // clang-format off
- optional_args << "use_fec_from_device " << blk_device
- << " fec_roots " << hashtree_desc.fec_num_roots
- << " fec_blocks " << hashtree_desc.fec_offset / hashtree_desc.data_block_size
- << " fec_start " << hashtree_desc.fec_offset / hashtree_desc.data_block_size
- << " ";
- // clang-format on
+ target.UseFec(blk_device, hashtree_desc.fec_num_roots,
+ hashtree_desc.fec_offset / hashtree_desc.data_block_size,
+ hashtree_desc.fec_offset / hashtree_desc.data_block_size);
}
-
if (!dm_verity_mode.empty()) {
- optional_argc += 1;
- optional_args << dm_verity_mode << " ";
+ target.SetVerityMode(dm_verity_mode);
}
-
// Always use ignore_zero_blocks.
- optional_argc += 1;
- optional_args << "ignore_zero_blocks";
+ target.IgnoreZeroBlocks();
- verity_table << " " << optional_argc << " " << optional_args.str();
- return verity_table.str();
-}
+ LINFO << "Built verity table: '" << target.GetParameterString() << "'";
-static bool load_verity_table(struct dm_ioctl* io, const std::string& dm_device_name, int fd,
- uint64_t image_size, const std::string& verity_table) {
- fs_mgr_dm_ioctl_init(io, DM_BUF_SIZE, dm_device_name);
-
- // The buffer consists of [dm_ioctl][dm_target_spec][verity_params].
- char* buffer = (char*)io;
-
- // Builds the dm_target_spec arguments.
- struct dm_target_spec* dm_target = (struct dm_target_spec*)&buffer[sizeof(struct dm_ioctl)];
- io->flags = DM_READONLY_FLAG;
- io->target_count = 1;
- dm_target->status = 0;
- dm_target->sector_start = 0;
- dm_target->length = image_size / 512;
- strcpy(dm_target->target_type, "verity");
-
- // Builds the verity params.
- char* verity_params = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec);
- size_t bufsize = DM_BUF_SIZE - (verity_params - buffer);
-
- LINFO << "Loading verity table: '" << verity_table << "'";
-
- // Copies verity_table to verity_params (including the terminating null byte).
- if (verity_table.size() > bufsize - 1) {
- LERROR << "Verity table size too large: " << verity_table.size()
- << " (max allowable size: " << bufsize - 1 << ")";
- return false;
- }
- memcpy(verity_params, verity_table.c_str(), verity_table.size() + 1);
-
- // Sets ext target boundary.
- verity_params += verity_table.size() + 1;
- verity_params = (char*)(((unsigned long)verity_params + 7) & ~7);
- dm_target->next = verity_params - buffer;
-
- // Sends the ioctl to load the verity table.
- if (ioctl(fd, DM_TABLE_LOAD, io)) {
- PERROR << "Error loading verity table";
- return false;
- }
-
- return true;
+ return table->AddTarget(std::make_unique<android::dm::DmTargetVerity>(target));
}
static bool hashtree_dm_verity_setup(struct fstab_rec* fstab_entry,
const AvbHashtreeDescriptor& hashtree_desc,
const std::string& salt, const std::string& root_digest,
bool wait_for_verity_dev) {
- // Gets the device mapper fd.
- android::base::unique_fd fd(open("/dev/device-mapper", O_RDWR));
- if (fd < 0) {
- PERROR << "Error opening device mapper";
+ android::dm::DmTable table;
+ if (!construct_verity_table(hashtree_desc, salt, root_digest, fstab_entry->blk_device, &table) ||
+ !table.valid()) {
+ LERROR << "Failed to construct verity table.";
return false;
}
+ table.set_readonly(true);
- // Creates the device.
- alignas(dm_ioctl) char buffer[DM_BUF_SIZE];
- struct dm_ioctl* io = (struct dm_ioctl*)buffer;
const std::string mount_point(basename(fstab_entry->mount_point));
- if (!fs_mgr_dm_create_device(io, mount_point, fd)) {
+ android::dm::DeviceMapper& dm = android::dm::DeviceMapper::Instance();
+ if (!dm.CreateDevice(mount_point, table)) {
LERROR << "Couldn't create verity device!";
return false;
}
- // Gets the name of the device file.
- std::string verity_blk_name;
- if (!fs_mgr_dm_get_device_name(io, mount_point, fd, &verity_blk_name)) {
- LERROR << "Couldn't get verity device number!";
- return false;
- }
-
- std::string verity_table =
- construct_verity_table(hashtree_desc, salt, root_digest, fstab_entry->blk_device);
- if (verity_table.empty()) {
- LERROR << "Failed to construct verity table.";
- return false;
- }
-
- // Loads the verity mapping table.
- if (!load_verity_table(io, mount_point, fd, hashtree_desc.image_size, verity_table)) {
- LERROR << "Couldn't load verity table!";
- return false;
- }
-
- // Activates the device.
- if (!fs_mgr_dm_resume_table(io, mount_point, fd)) {
+ std::string dev_path;
+ if (!dm.GetDmDevicePathByName(mount_point, &dev_path)) {
+ LERROR << "Couldn't get verity device path!";
return false;
}
@@ -382,10 +293,10 @@
// Updates fstab_rec->blk_device to verity device name.
free(fstab_entry->blk_device);
- fstab_entry->blk_device = strdup(verity_blk_name.c_str());
+ fstab_entry->blk_device = strdup(dev_path.c_str());
// Makes sure we've set everything up properly.
- if (wait_for_verity_dev && !fs_mgr_wait_for_file(verity_blk_name, 1s)) {
+ if (wait_for_verity_dev && !fs_mgr_wait_for_file(dev_path, 1s)) {
return false;
}
diff --git a/fs_mgr/libdm/dm_table.cpp b/fs_mgr/libdm/dm_table.cpp
index cb6f210..15c7ce1 100644
--- a/fs_mgr/libdm/dm_table.cpp
+++ b/fs_mgr/libdm/dm_table.cpp
@@ -23,6 +23,9 @@
namespace dm {
bool DmTable::AddTarget(std::unique_ptr<DmTarget>&& target) {
+ if (!target->Valid()) {
+ return false;
+ }
targets_.push_back(std::move(target));
return true;
}
diff --git a/fs_mgr/libdm/dm_target.cpp b/fs_mgr/libdm/dm_target.cpp
index 5934416..20b26df 100644
--- a/fs_mgr/libdm/dm_target.cpp
+++ b/fs_mgr/libdm/dm_target.cpp
@@ -18,6 +18,7 @@
#include <android-base/logging.h>
#include <android-base/macros.h>
+#include <android-base/strings.h>
#include <libdm/dm.h>
@@ -55,5 +56,60 @@
return block_device_ + " " + std::to_string(physical_sector_);
}
+DmTargetVerity::DmTargetVerity(uint64_t start, uint64_t length, uint32_t version,
+ const std::string& block_device, const std::string& hash_device,
+ uint32_t data_block_size, uint32_t hash_block_size,
+ uint32_t num_data_blocks, uint32_t hash_start_block,
+ const std::string& hash_algorithm, const std::string& root_digest,
+ const std::string& salt)
+ : DmTarget(start, length), valid_(true) {
+ base_args_ = {
+ std::to_string(version),
+ block_device,
+ hash_device,
+ std::to_string(data_block_size),
+ std::to_string(hash_block_size),
+ std::to_string(num_data_blocks),
+ std::to_string(hash_start_block),
+ hash_algorithm,
+ root_digest,
+ salt,
+ };
+}
+
+void DmTargetVerity::UseFec(const std::string& device, uint32_t num_roots, uint32_t num_blocks,
+ uint32_t start) {
+ optional_args_.emplace_back("use_fec_from_device");
+ optional_args_.emplace_back(device);
+ optional_args_.emplace_back("fec_roots");
+ optional_args_.emplace_back(std::to_string(num_roots));
+ optional_args_.emplace_back("fec_blocks");
+ optional_args_.emplace_back(std::to_string(num_blocks));
+ optional_args_.emplace_back("fec_start");
+ optional_args_.emplace_back(std::to_string(start));
+}
+
+void DmTargetVerity::SetVerityMode(const std::string& mode) {
+ if (mode != "restart_on_corruption" && mode != "ignore_corruption") {
+ LOG(ERROR) << "Unknown verity mode: " << mode;
+ valid_ = false;
+ return;
+ }
+ optional_args_.emplace_back(mode);
+}
+
+void DmTargetVerity::IgnoreZeroBlocks() {
+ optional_args_.emplace_back("ignore_zero_blocks");
+}
+
+std::string DmTargetVerity::GetParameterString() const {
+ std::string base = android::base::Join(base_args_, " ");
+ if (optional_args_.empty()) {
+ return base;
+ }
+ std::string optional = android::base::Join(optional_args_, " ");
+ return base + " " + std::to_string(optional_args_.size()) + " " + optional;
+}
+
} // namespace dm
} // namespace android
diff --git a/fs_mgr/libdm/dm_test.cpp b/fs_mgr/libdm/dm_test.cpp
index 67dc958..85f8e4a 100644
--- a/fs_mgr/libdm/dm_test.cpp
+++ b/fs_mgr/libdm/dm_test.cpp
@@ -164,3 +164,25 @@
// test should ensure that device deletion works.
ASSERT_TRUE(dev.Destroy());
}
+
+TEST(libdm, DmVerityArgsAvb2) {
+ std::string device = "/dev/block/platform/soc/1da4000.ufshc/by-name/vendor_a";
+ std::string algorithm = "sha1";
+ std::string digest = "4be7e823b8c40f7bd5c8ccd5123f0722c5baca21";
+ std::string salt = "cc99f81ecb9484220a003b0719ee59dcf9be7e5d";
+
+ DmTargetVerity target(0, 10000, 1, device, device, 4096, 4096, 125961, 125961, algorithm,
+ digest, salt);
+ target.UseFec(device, 2, 126955, 126955);
+ target.SetVerityMode("restart_on_corruption");
+ target.IgnoreZeroBlocks();
+
+ // Verity table from a walleye build.
+ std::string expected =
+ "1 /dev/block/platform/soc/1da4000.ufshc/by-name/vendor_a "
+ "/dev/block/platform/soc/1da4000.ufshc/by-name/vendor_a 4096 4096 125961 125961 sha1 "
+ "4be7e823b8c40f7bd5c8ccd5123f0722c5baca21 cc99f81ecb9484220a003b0719ee59dcf9be7e5d 10 "
+ "use_fec_from_device /dev/block/platform/soc/1da4000.ufshc/by-name/vendor_a fec_roots "
+ "2 fec_blocks 126955 fec_start 126955 restart_on_corruption ignore_zero_blocks";
+ EXPECT_EQ(target.GetParameterString(), expected);
+}
diff --git a/fs_mgr/libdm/include/libdm/dm_target.h b/fs_mgr/libdm/include/libdm/dm_target.h
index 8fb49ac..346758a 100644
--- a/fs_mgr/libdm/include/libdm/dm_target.h
+++ b/fs_mgr/libdm/include/libdm/dm_target.h
@@ -21,6 +21,7 @@
#include <stdint.h>
#include <string>
+#include <vector>
#include <android-base/logging.h>
@@ -69,6 +70,8 @@
// must implement this, for it to be used on a device.
std::string Serialize() const;
+ virtual bool Valid() const { return true; }
+
protected:
// Get the parameter string that is passed to the end of the dm_target_spec
// for this target type.
@@ -103,6 +106,28 @@
uint64_t physical_sector_;
};
+class DmTargetVerity final : public DmTarget {
+ public:
+ DmTargetVerity(uint64_t start, uint64_t length, uint32_t version,
+ const std::string& block_device, const std::string& hash_device,
+ uint32_t data_block_size, uint32_t hash_block_size, uint32_t num_data_blocks,
+ uint32_t hash_start_block, const std::string& hash_algorithm,
+ const std::string& root_digest, const std::string& salt);
+
+ void UseFec(const std::string& device, uint32_t num_roots, uint32_t num_blocks, uint32_t start);
+ void SetVerityMode(const std::string& mode);
+ void IgnoreZeroBlocks();
+
+ std::string name() const override { return "verity"; }
+ std::string GetParameterString() const override;
+ bool Valid() const override { return valid_; }
+
+ private:
+ std::vector<std::string> base_args_;
+ std::vector<std::string> optional_args_;
+ bool valid_;
+};
+
} // namespace dm
} // namespace android