mirror of
https://github.com/edera-dev/sprout.git
synced 2026-11-04 23:52:22 +00:00
alex
8b94ebe5bd
Load options were decoded with CStr16::from_u16_with_nul, which needs an even byte count and exactly one null at the very end. Firmware that passed an odd size, left off the null terminator, or padded the string with extra nulls made argument parsing fail, and Sprout refused to boot. Decode the raw bytes as little-endian UTF-16 up to the first null instead, replacing anything that isn't valid.
69 lines
2.6 KiB
Rust
69 lines
2.6 KiB
Rust
use alloc::string::{String, ToString};
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use alloc::vec::Vec;
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use anyhow::{Context, Result};
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use uefi::proto::loaded_image::LoadedImage;
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/// Loads the command-line arguments passed to the current image.
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pub fn args() -> Result<Vec<String>> {
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// Acquire the current image handle.
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let handle = uefi::boot::image_handle();
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// Open the LoadedImage protocol for the current image.
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let loaded_image = uefi::boot::open_protocol_exclusive::<LoadedImage>(handle)
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.context("unable to open loaded image protocol for current image")?;
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// Load the command-line argument string.
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// Load options are usually a null-terminated UCS-2 string, but firmware is not consistent
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// about this. Some firmware passes an odd number of bytes, leaves off the null terminator,
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// or pads the string with extra nulls. We decode everything up to the first null and
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// replace anything that isn't valid UCS-2, instead of refusing to boot.
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let Some(options) = loaded_image.load_options_as_bytes() else {
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// No load options were passed. We will return an empty vector.
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return Ok(Vec::new());
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};
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// Decode the options as little-endian UTF-16, stopping at the first null.
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// A trailing odd byte can't be part of a character, so it is dropped.
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let options = options
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.as_chunks::<2>()
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.0
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.iter()
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.map(|pair| u16::from_le_bytes(*pair))
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.take_while(|c| *c != 0)
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.collect::<Vec<u16>>();
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let options = String::from_utf16_lossy(&options);
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// Use shlex to parse the options.
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// If shlex fails, we will perform a simple whitespace split.
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let mut args = shlex::split(&options).unwrap_or_else(|| {
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options
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.split_ascii_whitespace()
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.map(|string| string.to_string())
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.collect::<Vec<_>>()
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});
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// Correct firmware that may add invalid arguments at the start.
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// Witnessed this on a Dell Precision 5690 when direct booting.
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args = args
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.into_iter()
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.skip_while(|arg| {
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arg.chars()
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.next()
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// Filter out unprintable characters and backticks.
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// Both of which have been observed in the wild.
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.map(|c| c.is_ascii_control() || c == '`')
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.unwrap_or(false)
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})
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.collect();
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// If there is a first argument, check if it is not an option.
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// If it is not, we will assume it is the path to the executable and remove it.
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if let Some(arg) = args.first()
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&& !arg.starts_with('-')
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{
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args.remove(0);
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}
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Ok(args)
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}
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