[avb] Refator descriptor module to allow multiple descriptor types
Before this cl, only hash descriptors were allowed in the kernel
avb footer. This cl refactors the descriptor module in pvmfw_avb
to make it easier to add other types of descriptors.
Test: atest libpvmfw_avb.integration_test
Bug: 279557218
Change-Id: I22b8b06598fc7119c7cc3929a6fb053fc6763f02
diff --git a/pvmfw/avb/src/descriptor.rs b/pvmfw/avb/src/descriptor.rs
deleted file mode 100644
index cd623ac..0000000
--- a/pvmfw/avb/src/descriptor.rs
+++ /dev/null
@@ -1,201 +0,0 @@
-// Copyright 2023, The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//! Structs and functions relating to the descriptors.
-
-use crate::error::{AvbIOError, AvbSlotVerifyError};
-use crate::partition::PartitionName;
-use crate::utils::{self, is_not_null, to_nonnull, to_usize, usize_checked_add};
-use avb_bindgen::{
- avb_descriptor_foreach, avb_hash_descriptor_validate_and_byteswap, AvbDescriptor,
- AvbHashDescriptor, AvbVBMetaData, AVB_SHA256_DIGEST_SIZE,
-};
-use core::{
- ffi::c_void,
- mem::{size_of, MaybeUninit},
- ops::Range,
- slice,
-};
-use tinyvec::ArrayVec;
-
-/// Digest type for kernel and initrd.
-pub type Digest = [u8; AVB_SHA256_DIGEST_SIZE as usize];
-
-/// `HashDescriptors` can have maximum one `HashDescriptor` per known partition.
-#[derive(Default)]
-pub(crate) struct HashDescriptors(
- ArrayVec<[HashDescriptor; PartitionName::NUM_OF_KNOWN_PARTITIONS]>,
-);
-
-impl HashDescriptors {
- /// Builds `HashDescriptors` from `AvbVBMetaData`.
- /// Returns an error if the given `AvbVBMetaData` contains non-hash descriptor, hash
- /// descriptor of unknown `PartitionName` or duplicated hash descriptors.
- ///
- /// # Safety
- ///
- /// Behavior is undefined if any of the following conditions are violated:
- /// * `vbmeta.vbmeta_data` must be non-null and points to a valid VBMeta.
- /// * `vbmeta.vbmeta_data` must be valid for reading `vbmeta.vbmeta_size` bytes.
- pub(crate) unsafe fn from_vbmeta(vbmeta: AvbVBMetaData) -> Result<Self, AvbSlotVerifyError> {
- is_not_null(vbmeta.vbmeta_data).map_err(|_| AvbSlotVerifyError::Io)?;
- let mut descriptors = Self::default();
- // SAFETY: It is safe as the raw pointer `vbmeta.vbmeta_data` is a non-null pointer and
- // points to a valid VBMeta structure.
- if !unsafe {
- avb_descriptor_foreach(
- vbmeta.vbmeta_data,
- vbmeta.vbmeta_size,
- Some(check_and_save_descriptor),
- &mut descriptors as *mut _ as *mut c_void,
- )
- } {
- return Err(AvbSlotVerifyError::InvalidMetadata);
- }
- Ok(descriptors)
- }
-
- fn push(&mut self, descriptor: HashDescriptor) -> utils::Result<()> {
- if self.0.iter().any(|d| d.partition_name_eq(&descriptor)) {
- return Err(AvbIOError::Io);
- }
- self.0.push(descriptor);
- Ok(())
- }
-
- pub(crate) fn len(&self) -> usize {
- self.0.len()
- }
-
- /// Finds the `HashDescriptor` for the given `PartitionName`.
- /// Throws an error if no corresponding descriptor found.
- pub(crate) fn find(
- &self,
- partition_name: PartitionName,
- ) -> Result<&HashDescriptor, AvbSlotVerifyError> {
- self.0
- .iter()
- .find(|d| d.partition_name == partition_name)
- .ok_or(AvbSlotVerifyError::InvalidMetadata)
- }
-}
-
-/// # Safety
-///
-/// Behavior is undefined if any of the following conditions are violated:
-/// * The `descriptor` pointer must be non-null and points to a valid `AvbDescriptor` struct.
-/// * The `user_data` pointer must be non-null and points to a valid `HashDescriptors` struct.
-unsafe extern "C" fn check_and_save_descriptor(
- descriptor: *const AvbDescriptor,
- user_data: *mut c_void,
-) -> bool {
- // SAFETY: It is safe because the caller must ensure that the `descriptor` pointer and
- // the `user_data` are non-null and valid.
- unsafe { try_check_and_save_descriptor(descriptor, user_data).is_ok() }
-}
-
-/// # Safety
-///
-/// Behavior is undefined if any of the following conditions are violated:
-/// * The `descriptor` pointer must be non-null and points to a valid `AvbDescriptor` struct.
-/// * The `user_data` pointer must be non-null and points to a valid `HashDescriptors` struct.
-unsafe fn try_check_and_save_descriptor(
- descriptor: *const AvbDescriptor,
- user_data: *mut c_void,
-) -> utils::Result<()> {
- is_not_null(descriptor)?;
- // SAFETY: It is safe because the caller ensures that `descriptor` is a non-null pointer
- // pointing to a valid struct.
- let desc = unsafe { AvbHashDescriptorWrap::from_descriptor_ptr(descriptor)? };
- // SAFETY: It is safe because the caller ensures that `descriptor` is a non-null pointer
- // pointing to a valid struct.
- let data = unsafe { slice::from_raw_parts(descriptor as *const u8, desc.len()?) };
- let mut descriptors = to_nonnull(user_data as *mut HashDescriptors)?;
- // SAFETY: It is safe because the caller ensures that `user_data` is a non-null pointer
- // pointing to a valid struct.
- let descriptors = unsafe { descriptors.as_mut() };
- descriptors.push(HashDescriptor::new(&desc, data)?)
-}
-
-#[derive(Default)]
-pub(crate) struct HashDescriptor {
- partition_name: PartitionName,
- pub(crate) digest: Digest,
-}
-
-impl HashDescriptor {
- fn new(desc: &AvbHashDescriptorWrap, data: &[u8]) -> utils::Result<Self> {
- let partition_name = data
- .get(desc.partition_name_range()?)
- .ok_or(AvbIOError::RangeOutsidePartition)?
- .try_into()?;
- let partition_digest =
- data.get(desc.digest_range()?).ok_or(AvbIOError::RangeOutsidePartition)?;
- let mut digest = [0u8; size_of::<Digest>()];
- digest.copy_from_slice(partition_digest);
- Ok(Self { partition_name, digest })
- }
-
- fn partition_name_eq(&self, other: &HashDescriptor) -> bool {
- self.partition_name == other.partition_name
- }
-}
-
-/// `AvbHashDescriptor` contains the metadata for the given descriptor.
-struct AvbHashDescriptorWrap(AvbHashDescriptor);
-
-impl AvbHashDescriptorWrap {
- /// # Safety
- ///
- /// Behavior is undefined if any of the following conditions are violated:
- /// * The `descriptor` pointer must be non-null and point to a valid `AvbDescriptor`.
- unsafe fn from_descriptor_ptr(descriptor: *const AvbDescriptor) -> utils::Result<Self> {
- is_not_null(descriptor)?;
- // SAFETY: It is safe as the raw pointer `descriptor` is non-null and points to
- // a valid `AvbDescriptor`.
- let desc = unsafe {
- let mut desc = MaybeUninit::uninit();
- if !avb_hash_descriptor_validate_and_byteswap(
- descriptor as *const AvbHashDescriptor,
- desc.as_mut_ptr(),
- ) {
- return Err(AvbIOError::Io);
- }
- desc.assume_init()
- };
- Ok(Self(desc))
- }
-
- fn len(&self) -> utils::Result<usize> {
- usize_checked_add(
- size_of::<AvbDescriptor>(),
- to_usize(self.0.parent_descriptor.num_bytes_following)?,
- )
- }
-
- fn partition_name_end(&self) -> utils::Result<usize> {
- usize_checked_add(size_of::<AvbHashDescriptor>(), to_usize(self.0.partition_name_len)?)
- }
-
- fn partition_name_range(&self) -> utils::Result<Range<usize>> {
- let start = size_of::<AvbHashDescriptor>();
- Ok(start..(self.partition_name_end()?))
- }
-
- fn digest_range(&self) -> utils::Result<Range<usize>> {
- let start = usize_checked_add(self.partition_name_end()?, to_usize(self.0.salt_len)?)?;
- let end = usize_checked_add(start, to_usize(self.0.digest_len)?)?;
- Ok(start..end)
- }
-}
diff --git a/pvmfw/avb/src/descriptor/descriptors.rs b/pvmfw/avb/src/descriptor/descriptors.rs
new file mode 100644
index 0000000..b577adf
--- /dev/null
+++ b/pvmfw/avb/src/descriptor/descriptors.rs
@@ -0,0 +1,140 @@
+// Copyright 2023, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Structs and functions relating to the descriptor data.
+
+use crate::error::AvbIOError;
+use crate::partition::PartitionName;
+use crate::utils::{self, is_not_null, to_usize, usize_checked_add};
+use crate::Digest;
+use avb_bindgen::{
+ avb_descriptor_validate_and_byteswap, avb_hash_descriptor_validate_and_byteswap, AvbDescriptor,
+ AvbDescriptorTag, AvbHashDescriptor,
+};
+use core::{
+ mem::{size_of, MaybeUninit},
+ ops::Range,
+ slice,
+};
+
+pub(super) enum Descriptor {
+ Hash(HashDescriptor),
+}
+
+impl Descriptor {
+ /// # Safety
+ ///
+ /// Behavior is undefined if any of the following conditions are violated:
+ /// * The `descriptor` pointer must be non-null and point to a valid `AvbDescriptor`.
+ pub(super) unsafe fn from_descriptor_ptr(
+ descriptor: *const AvbDescriptor,
+ ) -> utils::Result<Self> {
+ // SAFETY: It is safe as the raw pointer `descriptor` is non-null and points to
+ // a valid `AvbDescriptor`.
+ let avb_descriptor =
+ unsafe { get_valid_descriptor(descriptor, avb_descriptor_validate_and_byteswap)? };
+ let len = usize_checked_add(
+ size_of::<AvbDescriptor>(),
+ to_usize(avb_descriptor.num_bytes_following)?,
+ )?;
+ // SAFETY: It is safe because the caller ensures that `descriptor` is a non-null pointer
+ // pointing to a valid struct.
+ let data = unsafe { slice::from_raw_parts(descriptor as *const u8, len) };
+ match avb_descriptor.tag.try_into() {
+ Ok(AvbDescriptorTag::AVB_DESCRIPTOR_TAG_HASH) => {
+ // SAFETY: It is safe because the caller ensures that `descriptor` is a non-null
+ // pointer pointing to a valid struct.
+ let h = unsafe { HashDescriptorHeader::from_descriptor_ptr(descriptor)? };
+ Ok(Self::Hash(HashDescriptor::new(&h, data)?))
+ }
+ _ => Err(AvbIOError::NoSuchValue),
+ }
+ }
+}
+
+struct HashDescriptorHeader(AvbHashDescriptor);
+
+impl HashDescriptorHeader {
+ /// # Safety
+ ///
+ /// Behavior is undefined if any of the following conditions are violated:
+ /// * The `descriptor` pointer must be non-null and point to a valid `AvbDescriptor`.
+ unsafe fn from_descriptor_ptr(descriptor: *const AvbDescriptor) -> utils::Result<Self> {
+ // SAFETY: It is safe as the raw pointer `descriptor` is non-null and points to
+ // a valid `AvbDescriptor`.
+ unsafe {
+ get_valid_descriptor(
+ descriptor as *const AvbHashDescriptor,
+ avb_hash_descriptor_validate_and_byteswap,
+ )
+ .map(Self)
+ }
+ }
+
+ fn partition_name_end(&self) -> utils::Result<usize> {
+ usize_checked_add(size_of::<AvbHashDescriptor>(), to_usize(self.0.partition_name_len)?)
+ }
+
+ fn partition_name_range(&self) -> utils::Result<Range<usize>> {
+ let start = size_of::<AvbHashDescriptor>();
+ Ok(start..(self.partition_name_end()?))
+ }
+
+ fn digest_range(&self) -> utils::Result<Range<usize>> {
+ let start = usize_checked_add(self.partition_name_end()?, to_usize(self.0.salt_len)?)?;
+ let end = usize_checked_add(start, to_usize(self.0.digest_len)?)?;
+ Ok(start..end)
+ }
+}
+
+/// # Safety
+///
+/// Behavior is undefined if any of the following conditions are violated:
+/// * The `descriptor_ptr` pointer must be non-null and point to a valid `AvbDescriptor`.
+unsafe fn get_valid_descriptor<T>(
+ descriptor_ptr: *const T,
+ descriptor_validate_and_byteswap: unsafe extern "C" fn(src: *const T, dest: *mut T) -> bool,
+) -> utils::Result<T> {
+ is_not_null(descriptor_ptr)?;
+ // SAFETY: It is safe because the caller ensures that `descriptor_ptr` is a non-null pointer
+ // pointing to a valid struct.
+ let descriptor = unsafe {
+ let mut desc = MaybeUninit::uninit();
+ if !descriptor_validate_and_byteswap(descriptor_ptr, desc.as_mut_ptr()) {
+ return Err(AvbIOError::Io);
+ }
+ desc.assume_init()
+ };
+ Ok(descriptor)
+}
+
+#[derive(Default)]
+pub(crate) struct HashDescriptor {
+ pub(crate) partition_name: PartitionName,
+ pub(crate) digest: Digest,
+}
+
+impl HashDescriptor {
+ fn new(desc: &HashDescriptorHeader, data: &[u8]) -> utils::Result<Self> {
+ let partition_name = data
+ .get(desc.partition_name_range()?)
+ .ok_or(AvbIOError::RangeOutsidePartition)?
+ .try_into()?;
+ let partition_digest =
+ data.get(desc.digest_range()?).ok_or(AvbIOError::RangeOutsidePartition)?;
+ let mut digest = [0u8; size_of::<Digest>()];
+ digest.copy_from_slice(partition_digest);
+ Ok(Self { partition_name, digest })
+ }
+}
diff --git a/pvmfw/avb/src/descriptor/mod.rs b/pvmfw/avb/src/descriptor/mod.rs
new file mode 100644
index 0000000..67f85d9
--- /dev/null
+++ b/pvmfw/avb/src/descriptor/mod.rs
@@ -0,0 +1,129 @@
+// Copyright 2023, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Structs and functions relating to the descriptors.
+
+mod descriptors;
+
+pub(crate) use self::descriptors::HashDescriptor;
+
+use self::descriptors::Descriptor;
+use crate::error::{AvbIOError, AvbSlotVerifyError};
+use crate::partition::PartitionName;
+use crate::utils::{self, is_not_null, to_nonnull};
+use avb_bindgen::{avb_descriptor_foreach, AvbDescriptor, AvbVBMetaData, AVB_SHA256_DIGEST_SIZE};
+use core::ffi::c_void;
+use tinyvec::ArrayVec;
+
+/// Digest type for kernel and initrd.
+pub type Digest = [u8; AVB_SHA256_DIGEST_SIZE as usize];
+
+/// `Descriptors` can have at most one `HashDescriptor` per known partition and at most one
+/// `PropertyDescriptor`.
+#[derive(Default)]
+pub(crate) struct Descriptors {
+ hash_descriptors: ArrayVec<[HashDescriptor; PartitionName::NUM_OF_KNOWN_PARTITIONS]>,
+}
+
+impl Descriptors {
+ /// Builds `Descriptors` from `AvbVBMetaData`.
+ /// Returns an error if the given `AvbVBMetaData` contains non-hash descriptor, hash
+ /// descriptor of unknown `PartitionName` or duplicated hash descriptors.
+ ///
+ /// # Safety
+ ///
+ /// Behavior is undefined if any of the following conditions are violated:
+ /// * `vbmeta.vbmeta_data` must be non-null and points to a valid VBMeta.
+ /// * `vbmeta.vbmeta_data` must be valid for reading `vbmeta.vbmeta_size` bytes.
+ pub(crate) unsafe fn from_vbmeta(vbmeta: AvbVBMetaData) -> Result<Self, AvbSlotVerifyError> {
+ is_not_null(vbmeta.vbmeta_data).map_err(|_| AvbSlotVerifyError::Io)?;
+ let mut descriptors = Self::default();
+ // SAFETY: It is safe as the raw pointer `vbmeta.vbmeta_data` is a non-null pointer and
+ // points to a valid VBMeta structure.
+ if !unsafe {
+ avb_descriptor_foreach(
+ vbmeta.vbmeta_data,
+ vbmeta.vbmeta_size,
+ Some(check_and_save_descriptor),
+ &mut descriptors as *mut _ as *mut c_void,
+ )
+ } {
+ return Err(AvbSlotVerifyError::InvalidMetadata);
+ }
+ Ok(descriptors)
+ }
+
+ pub(crate) fn num_hash_descriptor(&self) -> usize {
+ self.hash_descriptors.len()
+ }
+
+ /// Finds the `HashDescriptor` for the given `PartitionName`.
+ /// Throws an error if no corresponding descriptor found.
+ pub(crate) fn find_hash_descriptor(
+ &self,
+ partition_name: PartitionName,
+ ) -> Result<&HashDescriptor, AvbSlotVerifyError> {
+ self.hash_descriptors
+ .iter()
+ .find(|d| d.partition_name == partition_name)
+ .ok_or(AvbSlotVerifyError::InvalidMetadata)
+ }
+
+ fn push(&mut self, descriptor: Descriptor) -> utils::Result<()> {
+ match descriptor {
+ Descriptor::Hash(d) => self.push_hash_descriptor(d),
+ }
+ }
+
+ fn push_hash_descriptor(&mut self, descriptor: HashDescriptor) -> utils::Result<()> {
+ if self.hash_descriptors.iter().any(|d| d.partition_name == descriptor.partition_name) {
+ return Err(AvbIOError::Io);
+ }
+ self.hash_descriptors.push(descriptor);
+ Ok(())
+ }
+}
+
+/// # Safety
+///
+/// Behavior is undefined if any of the following conditions are violated:
+/// * The `descriptor` pointer must be non-null and points to a valid `AvbDescriptor` struct.
+/// * The `user_data` pointer must be non-null and points to a valid `Descriptors` struct.
+unsafe extern "C" fn check_and_save_descriptor(
+ descriptor: *const AvbDescriptor,
+ user_data: *mut c_void,
+) -> bool {
+ // SAFETY: It is safe because the caller must ensure that the `descriptor` pointer and
+ // the `user_data` are non-null and valid.
+ unsafe { try_check_and_save_descriptor(descriptor, user_data).is_ok() }
+}
+
+/// # Safety
+///
+/// Behavior is undefined if any of the following conditions are violated:
+/// * The `descriptor` pointer must be non-null and points to a valid `AvbDescriptor` struct.
+/// * The `user_data` pointer must be non-null and points to a valid `Descriptors` struct.
+unsafe fn try_check_and_save_descriptor(
+ descriptor: *const AvbDescriptor,
+ user_data: *mut c_void,
+) -> utils::Result<()> {
+ let mut descriptors = to_nonnull(user_data as *mut Descriptors)?;
+ // SAFETY: It is safe because the caller ensures that `user_data` is a non-null pointer
+ // pointing to a valid struct.
+ let descriptors = unsafe { descriptors.as_mut() };
+ // SAFETY: It is safe because the caller ensures that `descriptor` is a non-null pointer
+ // pointing to a valid struct.
+ let descriptor = unsafe { Descriptor::from_descriptor_ptr(descriptor)? };
+ descriptors.push(descriptor)
+}
diff --git a/pvmfw/avb/src/error.rs b/pvmfw/avb/src/error.rs
index 674e5a7..c2b7428 100644
--- a/pvmfw/avb/src/error.rs
+++ b/pvmfw/avb/src/error.rs
@@ -93,7 +93,6 @@
#[allow(dead_code)]
Oom,
/// AVB_IO_RESULT_ERROR_IO,
- #[allow(dead_code)]
Io,
/// AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION,
NoSuchPartition,
diff --git a/pvmfw/avb/src/verify.rs b/pvmfw/avb/src/verify.rs
index b03506c..05a6492 100644
--- a/pvmfw/avb/src/verify.rs
+++ b/pvmfw/avb/src/verify.rs
@@ -14,7 +14,7 @@
//! This module handles the pvmfw payload verification.
-use crate::descriptor::{Digest, HashDescriptors};
+use crate::descriptor::{Descriptors, Digest};
use crate::error::AvbSlotVerifyError;
use crate::ops::{Ops, Payload};
use crate::partition::PartitionName;
@@ -63,9 +63,9 @@
}
fn verify_vbmeta_has_only_one_hash_descriptor(
- hash_descriptors: &HashDescriptors,
+ descriptors: &Descriptors,
) -> Result<(), AvbSlotVerifyError> {
- if hash_descriptors.len() == 1 {
+ if descriptors.num_hash_descriptor() == 1 {
Ok(())
} else {
Err(AvbSlotVerifyError::InvalidMetadata)
@@ -112,11 +112,11 @@
// SAFETY: It is safe because the `vbmeta_image` is collected from `AvbSlotVerifyData`,
// which is returned by `avb_slot_verify()` when the verification succeeds. It is
// guaranteed by libavb to be non-null and to point to a valid VBMeta structure.
- let hash_descriptors = unsafe { HashDescriptors::from_vbmeta(vbmeta_image)? };
- let kernel_descriptor = hash_descriptors.find(PartitionName::Kernel)?;
+ let descriptors = unsafe { Descriptors::from_vbmeta(vbmeta_image)? };
+ let kernel_descriptor = descriptors.find_hash_descriptor(PartitionName::Kernel)?;
if initrd.is_none() {
- verify_vbmeta_has_only_one_hash_descriptor(&hash_descriptors)?;
+ verify_vbmeta_has_only_one_hash_descriptor(&descriptors)?;
return Ok(VerifiedBootData {
debug_level: DebugLevel::None,
kernel_digest: kernel_descriptor.digest,
@@ -140,7 +140,7 @@
initrd_partition_name,
initrd.len(),
)?;
- let initrd_descriptor = hash_descriptors.find(initrd_partition_name)?;
+ let initrd_descriptor = descriptors.find_hash_descriptor(initrd_partition_name)?;
Ok(VerifiedBootData {
debug_level,
kernel_digest: kernel_descriptor.digest,