From 9803fbf30b7847d27f1f8bf024c2d51363bcd998 Mon Sep 17 00:00:00 2001 From: David Anderson Date: Mon, 25 Jun 2018 16:12:21 -0700 Subject: [PATCH] fs_mgr: Use libdm for fs_mgr_verity. This change uses libdm to replace the hand-coded ioctl code in fs_mgr_verity. Since AVB2 is now preferred to AVB1, this is a surgical change to allow us to remove fs_mgr_dm_ioctl. Rather than refactor the target string construction code, we instead provide a DmTargetVerityString class which passes a raw parameter string directly to DmTable. Bug: 110035986 Test: AVB1 device still boots Change-Id: Iad88993a98abb388a12cec9e6d4543dfb4157414 --- fs_mgr/fs_mgr_verity.cpp | 94 +++++++------------------- fs_mgr/libdm/include/libdm/dm_target.h | 16 +++++ 2 files changed, 42 insertions(+), 68 deletions(-) diff --git a/fs_mgr/fs_mgr_verity.cpp b/fs_mgr/fs_mgr_verity.cpp index fe41f8ac2..5fb4ebba0 100644 --- a/fs_mgr/fs_mgr_verity.cpp +++ b/fs_mgr/fs_mgr_verity.cpp @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -44,7 +45,6 @@ #include "fs_mgr.h" #include "fs_mgr_priv.h" -#include "fs_mgr_priv_dm_ioctl.h" #define VERITY_TABLE_RSA_KEY "/verity_key" #define VERITY_TABLE_HASH_IDX 8 @@ -250,48 +250,27 @@ static bool format_legacy_verity_table(char *buf, const size_t bufsize, return true; } -static int load_verity_table(struct dm_ioctl *io, const std::string &name, - uint64_t device_size, int fd, - const struct verity_table_params *params, format_verity_table_func format) -{ - char *verity_params; - char *buffer = (char*) io; - size_t bufsize; +static int load_verity_table(android::dm::DeviceMapper& dm, const std::string& name, + uint64_t device_size, const struct verity_table_params* params, + format_verity_table_func format) { + android::dm::DmTable table; + table.set_readonly(true); - fs_mgr_dm_ioctl_init(io, DM_BUF_SIZE, name); - - struct dm_target_spec *tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)]; - - // set tgt arguments - io->target_count = 1; - io->flags = DM_READONLY_FLAG; - tgt->status = 0; - tgt->sector_start = 0; - tgt->length = device_size / 512; - strcpy(tgt->target_type, "verity"); - - // build the verity params - verity_params = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec); - bufsize = DM_BUF_SIZE - (verity_params - buffer); - - if (!format(verity_params, bufsize, params)) { + char buffer[DM_BUF_SIZE]; + if (!format(buffer, sizeof(buffer), params)) { LERROR << "Failed to format verity parameters"; return -1; } - LINFO << "loading verity table: '" << verity_params << "'"; - - // set next target boundary - verity_params += strlen(verity_params) + 1; - verity_params = (char*)(((uintptr_t)verity_params + 7) & ~7); - tgt->next = verity_params - buffer; - - // send the ioctl to load the verity table - if (ioctl(fd, DM_TABLE_LOAD, io)) { - PERROR << "Error loading verity table"; + android::dm::DmTargetVerityString target(0, device_size / 512, buffer); + if (!table.AddTarget(std::make_unique(target))) { + LERROR << "Failed to add verity target"; + return -1; + } + if (!dm.CreateDevice(name, table)) { + LERROR << "Failed to create verity device \"" << name << "\""; return -1; } - return 0; } @@ -761,11 +740,11 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab, bool wait_for_verity_dev) struct fec_verity_metadata verity; struct verity_table_params params = { .table = NULL }; - alignas(dm_ioctl) char buffer[DM_BUF_SIZE]; - struct dm_ioctl *io = (struct dm_ioctl *) buffer; const std::string mount_point(basename(fstab->mount_point)); bool verified_at_boot = false; + android::dm::DeviceMapper& dm = android::dm::DeviceMapper::Instance(); + if (fec_open(&f, fstab->blk_device, O_RDONLY, FEC_VERITY_DISABLE, FEC_DEFAULT_ROOTS) < 0) { PERROR << "Failed to open '" << fstab->blk_device << "'"; @@ -798,24 +777,6 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab, bool wait_for_verity_dev) params.ecc_dev = fstab->blk_device; - // get the device mapper fd - if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) { - PERROR << "Error opening device mapper"; - goto out; - } - - // create the device - if (!fs_mgr_dm_create_device(io, mount_point, fd)) { - LERROR << "Couldn't create verity device!"; - goto out; - } - - // get the name of the device file - if (!fs_mgr_dm_get_device_name(io, mount_point, fd, &verity_blk_name)) { - LERROR << "Couldn't get verity device number!"; - goto out; - } - if (load_verity_state(fstab, ¶ms.mode) < 0) { /* if accessing or updating the state failed, switch to the default * safe mode. This makes sure the device won't end up in an endless @@ -861,8 +822,7 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab, bool wait_for_verity_dev) fstab->fs_mgr_flags & MF_SLOTSELECT); // load the verity mapping table - if (load_verity_table(io, mount_point, verity.data_size, fd, ¶ms, - format_verity_table) == 0) { + if (load_verity_table(dm, mount_point, verity.data_size, ¶ms, format_verity_table) == 0) { goto loaded; } @@ -871,15 +831,14 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab, bool wait_for_verity_dev) LINFO << "Disabling error correction for " << mount_point.c_str(); params.ecc.valid = false; - if (load_verity_table(io, mount_point, verity.data_size, fd, ¶ms, - format_verity_table) == 0) { + if (load_verity_table(dm, mount_point, verity.data_size, ¶ms, format_verity_table) == 0) { goto loaded; } } // try the legacy format for backwards compatibility - if (load_verity_table(io, mount_point, verity.data_size, fd, ¶ms, - format_legacy_verity_table) == 0) { + if (load_verity_table(dm, mount_point, verity.data_size, ¶ms, format_legacy_verity_table) == + 0) { goto loaded; } @@ -888,8 +847,8 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab, bool wait_for_verity_dev) LINFO << "Falling back to EIO mode for " << mount_point.c_str(); params.mode = VERITY_MODE_EIO; - if (load_verity_table(io, mount_point, verity.data_size, fd, ¶ms, - format_legacy_verity_table) == 0) { + if (load_verity_table(dm, mount_point, verity.data_size, ¶ms, + format_legacy_verity_table) == 0) { goto loaded; } } @@ -898,9 +857,8 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab, bool wait_for_verity_dev) goto out; loaded: - - // activate the device - if (!fs_mgr_dm_resume_table(io, mount_point, fd)) { + if (!dm.GetDmDevicePathByName(mount_point, &verity_blk_name)) { + LERROR << "Couldn't get verity device number!"; goto out; } @@ -923,7 +881,7 @@ loaded: if (!verified_at_boot) { free(fstab->blk_device); fstab->blk_device = strdup(verity_blk_name.c_str()); - } else if (!fs_mgr_dm_destroy_device(io, mount_point, fd)) { + } else if (!dm.DeleteDevice(mount_point)) { LERROR << "Failed to remove verity device " << mount_point.c_str(); goto out; } diff --git a/fs_mgr/libdm/include/libdm/dm_target.h b/fs_mgr/libdm/include/libdm/dm_target.h index 346758ad3..d5974f4f1 100644 --- a/fs_mgr/libdm/include/libdm/dm_target.h +++ b/fs_mgr/libdm/include/libdm/dm_target.h @@ -128,6 +128,22 @@ class DmTargetVerity final : public DmTarget { bool valid_; }; +// This is the same as DmTargetVerity, but the table may be specified as a raw +// string. This code exists only for fs_mgr_verity and should be avoided. Use +// DmTargetVerity for new code instead. +class DmTargetVerityString final : public DmTarget { + public: + DmTargetVerityString(uint64_t start, uint64_t length, const std::string& target_string) + : DmTarget(start, length), target_string_(target_string) {} + + std::string name() const override { return "verity"; } + std::string GetParameterString() const override { return target_string_; } + bool Valid() const override { return true; } + + private: + std::string target_string_; +}; + } // namespace dm } // namespace android