diff options
author | Eric Biggers <ebiggers@google.com> | 2019-01-25 10:47:55 -0800 |
---|---|---|
committer | Eric Biggers <ebiggers@google.com> | 2019-01-25 13:42:02 -0800 |
commit | ed45ec3ae8bf2c18f72550bdf660035e2fee6dc4 (patch) | |
tree | a13000aaa0fb8e32bbc94de41c8c863cefe84b44 /cryptfs.cpp | |
parent | aaac873faf91fd540133e6fe8a041784b4ae16d1 (diff) | |
download | vold-ed45ec3ae8bf2c18f72550bdf660035e2fee6dc4.tar.gz |
cryptfs: round down dm-crypt device size to crypto sector boundary
This is needed to make adoptable storage volumes work with a 4K crypto
sector size when the block device size is not a multiple of 4K.
It is fine to do this because the filesystem ends on a 4K boundary
anyway and doesn't use any partial block at the end.
Bug: 123375298
Test: booted device configured to use FDE with sector size 4k, ran
'sm set-virtual-disk true' and formatted the virtual SD card as
adoptable storage. Then did the same but with a temporary patch
that changed kSizeVirtualDisk to be misaligned
Change-Id: I95ee6d7dcaaa8989c674aea9988c09116e830b0c
Diffstat (limited to 'cryptfs.cpp')
-rw-r--r-- | cryptfs.cpp | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/cryptfs.cpp b/cryptfs.cpp index ce01f1fb..01ac6948 100644 --- a/cryptfs.cpp +++ b/cryptfs.cpp @@ -35,6 +35,7 @@ #include "VolumeManager.h" #include "secontext.h" +#include <android-base/parseint.h> #include <android-base/properties.h> #include <android-base/stringprintf.h> #include <bootloader_message/bootloader_message.h> @@ -75,6 +76,7 @@ extern "C" { #include <crypto_scrypt.h> } +using android::base::ParseUint; using android::base::StringPrintf; using namespace std::chrono_literals; @@ -1046,19 +1048,37 @@ static std::string extra_params_as_string(const std::vector<std::string>& extra_ return extra_params; } -// Only adds parameters if the property is set. -static void add_sector_size_param(std::vector<std::string>* extra_params_vec) { +/* + * If the ro.crypto.fde_sector_size system property is set, append the + * parameters to make dm-crypt use the specified crypto sector size and round + * the crypto device size down to a crypto sector boundary. + */ +static int add_sector_size_param(std::vector<std::string>* extra_params_vec, + struct crypt_mnt_ftr* ftr) { constexpr char DM_CRYPT_SECTOR_SIZE[] = "ro.crypto.fde_sector_size"; - char sector_size[PROPERTY_VALUE_MAX]; + char value[PROPERTY_VALUE_MAX]; + + if (property_get(DM_CRYPT_SECTOR_SIZE, value, "") > 0) { + unsigned int sector_size; + + if (!ParseUint(value, §or_size) || sector_size < 512 || sector_size > 4096 || + (sector_size & (sector_size - 1)) != 0) { + SLOGE("Invalid value for %s: %s. Must be >= 512, <= 4096, and a power of 2\n", + DM_CRYPT_SECTOR_SIZE, value); + return -1; + } - if (property_get(DM_CRYPT_SECTOR_SIZE, sector_size, "") > 0) { - std::string param = StringPrintf("sector_size:%s", sector_size); + std::string param = StringPrintf("sector_size:%u", sector_size); extra_params_vec->push_back(std::move(param)); // With this option, IVs will match the sector numbering, instead // of being hard-coded to being based on 512-byte sectors. extra_params_vec->emplace_back("iv_large_sectors"); + + // Round the crypto device size down to a crypto sector boundary. + ftr->fs_size &= ~((sector_size / 512) - 1); } + return 0; } static int create_crypto_blk_dev(struct crypt_mnt_ftr* crypt_ftr, const unsigned char* master_key, @@ -1106,7 +1126,10 @@ static int create_crypto_blk_dev(struct crypt_mnt_ftr* crypt_ftr, const unsigned if (flags & CREATE_CRYPTO_BLK_DEV_FLAGS_ALLOW_ENCRYPT_OVERRIDE) { extra_params_vec.emplace_back("allow_encrypt_override"); } - add_sector_size_param(&extra_params_vec); + if (add_sector_size_param(&extra_params_vec, crypt_ftr)) { + SLOGE("Error processing dm-crypt sector size param\n"); + goto errout; + } load_count = load_crypto_mapping_table(crypt_ftr, master_key, real_blk_name, name, fd, extra_params_as_string(extra_params_vec).c_str()); if (load_count < 0) { |