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Message-ID: <20241115054616.1226735-6-alistair@alistair23.me>
Date: Fri, 15 Nov 2024 15:46:15 +1000
From: Alistair Francis <alistair@...stair23.me>
To: lukas@...ner.de,
Jonathan.Cameron@...wei.com,
linux-kernel@...r.kernel.org,
rust-for-linux@...r.kernel.org,
akpm@...ux-foundation.org,
bhelgaas@...gle.com,
linux-pci@...r.kernel.org,
linux-cxl@...r.kernel.org
Cc: bjorn3_gh@...tonmail.com,
ojeda@...nel.org,
tmgross@...ch.edu,
boqun.feng@...il.com,
benno.lossin@...ton.me,
a.hindborg@...nel.org,
wilfred.mallawa@....com,
alistair23@...il.com,
alex.gaynor@...il.com,
gary@...yguo.net,
aliceryhl@...gle.com,
Alistair Francis <alistair@...stair23.me>
Subject: [RFC 5/6] lib: rspdm: Support SPDM get_capabilities
Support the GET_CAPABILITIES SPDM command.
Signed-off-by: Alistair Francis <alistair@...stair23.me>
---
lib/rspdm/consts.rs | 18 ++++++++--
lib/rspdm/lib.rs | 4 +++
lib/rspdm/state.rs | 73 +++++++++++++++++++++++++++++++++++++++--
lib/rspdm/validator.rs | 74 ++++++++++++++++++++++++++++++++++++++++++
4 files changed, 164 insertions(+), 5 deletions(-)
diff --git a/lib/rspdm/consts.rs b/lib/rspdm/consts.rs
index e263d62fa648..d60f8302f389 100644
--- a/lib/rspdm/consts.rs
+++ b/lib/rspdm/consts.rs
@@ -11,9 +11,7 @@
/* SPDM versions supported by this implementation */
pub(crate) const SPDM_VER_10: u8 = 0x10;
-#[allow(dead_code)]
pub(crate) const SPDM_VER_11: u8 = 0x11;
-#[allow(dead_code)]
pub(crate) const SPDM_VER_12: u8 = 0x12;
pub(crate) const SPDM_VER_13: u8 = 0x13;
@@ -54,3 +52,19 @@ pub(crate) enum SpdmErrorCode {
pub(crate) const SPDM_GET_VERSION: u8 = 0x84;
pub(crate) const SPDM_GET_VERSION_LEN: usize = mem::size_of::<SpdmHeader>() + 255;
+
+pub(crate) const SPDM_GET_CAPABILITIES: u8 = 0xe1;
+pub(crate) const SPDM_MIN_DATA_TRANSFER_SIZE: u32 = 42;
+
+// SPDM cryptographic timeout of this implementation:
+// Assume calculations may take up to 1 sec on a busy machine, which equals
+// roughly 1 << 20. That's within the limits mandated for responders by CMA
+// (1 << 23 usec, PCIe r6.2 sec 6.31.3) and DOE (1 sec, PCIe r6.2 sec 6.30.2).
+// Used in GET_CAPABILITIES exchange.
+pub(crate) const SPDM_CTEXPONENT: u8 = 20;
+
+pub(crate) const SPDM_CERT_CAP: u32 = 1 << 1;
+pub(crate) const SPDM_CHAL_CAP: u32 = 1 << 2;
+
+pub(crate) const SPDM_REQ_CAPS: u32 = SPDM_CERT_CAP | SPDM_CHAL_CAP;
+pub(crate) const SPDM_RSP_MIN_CAPS: u32 = SPDM_CERT_CAP | SPDM_CHAL_CAP;
diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
index 670ecc02a471..bbd755854acd 100644
--- a/lib/rspdm/lib.rs
+++ b/lib/rspdm/lib.rs
@@ -111,6 +111,10 @@
return e.to_errno() as c_int;
}
+ if let Err(e) = state.get_capabilities() {
+ return e.to_errno() as c_int;
+ }
+
0
}
diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
index 9ace0bbaa21a..05a7faf17d47 100644
--- a/lib/rspdm/state.rs
+++ b/lib/rspdm/state.rs
@@ -16,10 +16,13 @@
};
use crate::consts::{
- SpdmErrorCode, SPDM_ERROR, SPDM_GET_VERSION, SPDM_GET_VERSION_LEN, SPDM_MAX_VER, SPDM_MIN_VER,
- SPDM_REQ,
+ SpdmErrorCode, SPDM_CTEXPONENT, SPDM_ERROR, SPDM_GET_CAPABILITIES, SPDM_GET_VERSION,
+ SPDM_GET_VERSION_LEN, SPDM_MAX_VER, SPDM_MIN_DATA_TRANSFER_SIZE, SPDM_MIN_VER, SPDM_REQ,
+ SPDM_REQ_CAPS, SPDM_RSP_MIN_CAPS, SPDM_VER_10, SPDM_VER_11, SPDM_VER_12,
+};
+use crate::validator::{
+ GetCapabilitiesReq, GetCapabilitiesRsp, GetVersionReq, GetVersionRsp, SpdmErrorRsp, SpdmHeader,
};
-use crate::validator::{GetVersionReq, GetVersionRsp, SpdmErrorRsp, SpdmHeader};
/// The current SPDM session state for a device. Based on the
/// C `struct spdm_state`.
@@ -35,6 +38,8 @@
///
/// @version: Maximum common supported version of requester and responder.
/// Negotiated during GET_VERSION exchange.
+/// @rsp_caps: Cached capabilities of responder.
+/// Received during GET_CAPABILITIES exchange.
///
/// @authenticated: Whether device was authenticated successfully.
#[allow(dead_code)]
@@ -48,6 +53,7 @@ pub struct SpdmState {
/* Negotiated state */
pub(crate) version: u8,
+ pub(crate) rsp_caps: u32,
pub(crate) authenticated: bool,
}
@@ -69,6 +75,7 @@ pub(crate) fn new(
keyring,
validate,
version: SPDM_MIN_VER,
+ rsp_caps: 0,
authenticated: false,
}
}
@@ -269,4 +276,64 @@ pub(crate) fn get_version(&mut self) -> Result<(), Error> {
Ok(())
}
+
+ /// Obtain the supported capabilities from an SPDM session and store the
+ /// information in the `SpdmState`.
+ pub(crate) fn get_capabilities(&mut self) -> Result<(), Error> {
+ let mut request = GetCapabilitiesReq::default();
+
+ request.version = self.version;
+ request.code = SPDM_GET_CAPABILITIES;
+ request.ctexponent = SPDM_CTEXPONENT;
+ request.flags = (SPDM_REQ_CAPS as u32).to_le();
+
+ let (req_sz, rsp_sz) = match self.version {
+ SPDM_VER_10 => (4, 8),
+ SPDM_VER_11 => (8, 8),
+ _ => {
+ request.data_transfer_size = self.transport_sz.to_le();
+ request.max_spdm_msg_size = request.data_transfer_size;
+
+ (
+ core::mem::size_of::<GetCapabilitiesReq>(),
+ core::mem::size_of::<GetCapabilitiesRsp>(),
+ )
+ }
+ };
+
+ // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
+ let request_buf = unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
+
+ let mut response_vec: KVec<u8> = KVec::with_capacity(rsp_sz, GFP_KERNEL)?;
+ // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
+ let response_buf = unsafe { from_raw_parts_mut(response_vec.as_mut_ptr(), rsp_sz) };
+
+ let rc = self.spdm_exchange(request_buf, response_buf)?;
+
+ if rc < (rsp_sz as i32) {
+ pr_err!("Truncated capabilities response\n");
+ to_result(-(bindings::EIO as i32))?;
+ }
+
+ // SAFETY: `rc` bytes where inserted to the raw pointer by spdm_exchange
+ unsafe { response_vec.set_len(rc as usize) };
+
+ let response: &mut GetCapabilitiesRsp =
+ Untrusted::new_mut(&mut response_vec).validate_mut()?;
+
+ self.rsp_caps = u32::from_le(response.flags);
+ if (self.rsp_caps & SPDM_RSP_MIN_CAPS) != SPDM_RSP_MIN_CAPS {
+ to_result(-(bindings::EPROTONOSUPPORT as i32))?;
+ }
+
+ if self.version >= SPDM_VER_12 {
+ if response.data_transfer_size < SPDM_MIN_DATA_TRANSFER_SIZE {
+ pr_err!("Malformed capabilities response\n");
+ to_result(-(bindings::EPROTO as i32))?;
+ }
+ self.transport_sz = self.transport_sz.min(response.data_transfer_size);
+ }
+
+ Ok(())
+ }
}
diff --git a/lib/rspdm/validator.rs b/lib/rspdm/validator.rs
index 05f1ba155920..cc998e70f235 100644
--- a/lib/rspdm/validator.rs
+++ b/lib/rspdm/validator.rs
@@ -117,3 +117,77 @@ fn validate(unvalidated: &mut Unvalidated<KVec<u8>>) -> Result<Self, Self::Err>
Ok(rsp)
}
}
+
+#[repr(C, packed)]
+pub(crate) struct GetCapabilitiesReq {
+ pub(crate) version: u8,
+ pub(crate) code: u8,
+ pub(crate) param1: u8,
+ pub(crate) param2: u8,
+
+ reserved1: u8,
+ pub(crate) ctexponent: u8,
+ reserved2: u16,
+
+ pub(crate) flags: u32,
+
+ /* End of SPDM 1.1 structure */
+ pub(crate) data_transfer_size: u32,
+ pub(crate) max_spdm_msg_size: u32,
+}
+
+impl Default for GetCapabilitiesReq {
+ fn default() -> Self {
+ GetCapabilitiesReq {
+ version: 0,
+ code: 0,
+ param1: 0,
+ param2: 0,
+ reserved1: 0,
+ ctexponent: 0,
+ reserved2: 0,
+ flags: 0,
+ data_transfer_size: 0,
+ max_spdm_msg_size: 0,
+ }
+ }
+}
+
+#[repr(C, packed)]
+pub(crate) struct GetCapabilitiesRsp {
+ pub(crate) version: u8,
+ pub(crate) code: u8,
+ pub(crate) param1: u8,
+ pub(crate) param2: u8,
+
+ reserved1: u8,
+ pub(crate) ctexponent: u8,
+ reserved2: u16,
+
+ pub(crate) flags: u32,
+
+ /* End of SPDM 1.1 structure */
+ pub(crate) data_transfer_size: u32,
+ pub(crate) max_spdm_msg_size: u32,
+
+ pub(crate) supported_algorithms: __IncompleteArrayField<__le16>,
+}
+
+impl Validate<&mut Unvalidated<KVec<u8>>> for &mut GetCapabilitiesRsp {
+ type Err = Error;
+
+ fn validate(unvalidated: &mut Unvalidated<KVec<u8>>) -> Result<Self, Self::Err> {
+ let raw = unvalidated.raw_mut();
+ if raw.len() < mem::size_of::<GetCapabilitiesRsp>() {
+ return Err(EINVAL);
+ }
+
+ let ptr = raw.as_mut_ptr();
+ // CAST: `GetCapabilitiesRsp` only contains integers and has `repr(C)`.
+ let ptr = ptr.cast::<GetCapabilitiesRsp>();
+ // SAFETY: `ptr` came from a reference and the cast above is valid.
+ let rsp: &mut GetCapabilitiesRsp = unsafe { &mut *ptr };
+
+ Ok(rsp)
+ }
+}
--
2.47.0
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