From 95d5fef771b63184012897d480476fd6b4177583 Mon Sep 17 00:00:00 2001
From: Rajas Paranjpe <52586855+ChocolateLoverRaj@users.noreply.github.com>
Date: Tue, 4 Jun 2024 22:00:11 -0700
Subject: [PATCH] set fp seed command

This command can only be run once per reboot (I'm pretty sure) so it can be hard to debug. Luckily it worked 1st try for me.
---
 crosec/src/commands/fp_set_seed.rs | 31 ++++++++++++++++++++++++++++++
 crosec/src/commands/mod.rs         |  2 ++
 ectool/src/main.rs                 | 20 +++++++++++++++++++
 3 files changed, 53 insertions(+)
 create mode 100644 crosec/src/commands/fp_set_seed.rs

diff --git a/crosec/src/commands/fp_set_seed.rs b/crosec/src/commands/fp_set_seed.rs
new file mode 100644
index 0000000..884e374
--- /dev/null
+++ b/crosec/src/commands/fp_set_seed.rs
@@ -0,0 +1,31 @@
+use std::ffi::c_int;
+
+use bytemuck::{Pod, Zeroable};
+
+use crate::{ec_command::ec_command_bytemuck, EcCmdResult};
+
+use super::CrosEcCmd;
+
+pub const FP_CONTEXT_TPM_BYTES: usize = 32;
+const FP_TEMPLATE_FORMAT_VERSION: u16 = 4;
+
+#[repr(C, align(4))]
+#[derive(Pod, Zeroable, Clone, Copy)]
+struct EcParamsFpSeed {
+    pub struct_version: u16,
+    pub reserved: u16,
+    pub seed: [u8; FP_CONTEXT_TPM_BYTES],
+}
+
+pub fn fp_set_seed(fd: c_int, seed: [u8; FP_CONTEXT_TPM_BYTES]) -> EcCmdResult<()> {
+    ec_command_bytemuck(
+        CrosEcCmd::FpSetSeed,
+        0,
+        &EcParamsFpSeed {
+            struct_version: FP_TEMPLATE_FORMAT_VERSION,
+            reserved: Default::default(),
+            seed,
+        },
+        fd,
+    )
+}
diff --git a/crosec/src/commands/mod.rs b/crosec/src/commands/mod.rs
index bf588ae..c77c42a 100644
--- a/crosec/src/commands/mod.rs
+++ b/crosec/src/commands/mod.rs
@@ -18,12 +18,14 @@ pub enum CrosEcCmd {
     ConsoleRead = 0x0098,
     FpInfo = 0x0403,
     FpStats = 0x0407,
+    FpSetSeed = 0x0408,
     BatteryGetStatic = 0x0600,
 }
 
 pub mod board_version;
 pub mod charge_control;
 pub mod fp_info;
+pub mod fp_set_seed;
 pub mod fp_stats;
 pub mod get_chip_info;
 pub mod get_cmd_versions;
diff --git a/ectool/src/main.rs b/ectool/src/main.rs
index f059d21..a5c0b90 100644
--- a/ectool/src/main.rs
+++ b/ectool/src/main.rs
@@ -4,6 +4,7 @@ use std::os::fd::AsRawFd;
 use clap::{Parser, Subcommand, ValueEnum};
 use color_eyre::eyre::Result;
 use crosec::commands::fp_info::fp_info;
+use crosec::commands::fp_set_seed::{fp_set_seed, FP_CONTEXT_TPM_BYTES};
 use crosec::commands::fp_stats::fp_stats;
 use crosec::commands::get_protocol_info::get_protocol_info;
 use num_traits::cast::FromPrimitive;
@@ -92,6 +93,9 @@ enum Commands {
     },
     FpInfo,
     FpStats,
+    FpSetSeed {
+        seed: String,
+    },
 }
 
 #[derive(Subcommand)]
@@ -280,6 +284,22 @@ fn main() -> Result<()> {
             let stats = fp_stats(fd)?;
             println!("{stats:#?}");
         }
+        Commands::FpSetSeed { seed } => {
+            match <Vec<u8> as TryInto<[u8; FP_CONTEXT_TPM_BYTES]>>::try_into(
+                seed.as_bytes().to_owned(),
+            ) {
+                Ok(seed) => {
+                    let file = File::open(CROS_FP_PATH).unwrap();
+                    let fd = file.as_raw_fd();
+                    fp_set_seed(fd, seed)?;
+                    println!("Set fp seed");
+                }
+                Err(seed) => {
+                    let seed_len = seed.len();
+                    println!("The seed must be {FP_CONTEXT_TPM_BYTES} bytes long. The seed you inputted is {seed_len} bytes long.");
+                }
+            }
+        }
     }
 
     Ok(())