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Make pcs_init compatible with multiple DSOs (#2488)

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* make pcs_init compatible with multiple DSOs

* clippy
This commit is contained in:
Addison Crump 2024-08-15 15:56:41 +02:00 committed by GitHub
parent 21051dc26f
commit f3433767be
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GPG Key ID: B5690EEEBB952194
1 changed files with 19 additions and 38 deletions
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57
libafl_targets/src/sancov_pcguard.rs
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@ -3,7 +3,7 @@
#[rustversion::nightly]
#[cfg(feature = "sancov_ngram4")]
use core::simd::num::SimdUint;
use core::{mem::align_of, ptr, slice};
use core::{mem::align_of, slice};
#[cfg(any(feature = "sancov_ngram4", feature = "sancov_ctx"))]
use libafl::executors::{hooks::ExecutorHook, HasObservers};
@ -61,6 +61,7 @@ pub static SHR_4: Ngram4 = Ngram4::from_array([1, 1, 1, 1]);
#[rustversion::nightly]
pub static SHR_8: Ngram8 = Ngram8::from_array([1, 1, 1, 1, 1, 1, 1, 1]);
use alloc::vec::Vec;
#[cfg(any(
feature = "sancov_ngram4",
feature = "sancov_ngram8",
@ -287,23 +288,27 @@ pub unsafe extern "C" fn __sanitizer_cov_trace_pc_guard_init(mut start: *mut u32
}
}
static mut PCS_BEG: *const usize = ptr::null();
static mut PCS_END: *const usize = ptr::null();
static mut PC_TABLES: Vec<&'static [PcTableEntry]> = Vec::new();
#[no_mangle]
unsafe extern "C" fn __sanitizer_cov_pcs_init(pcs_beg: *const usize, pcs_end: *const usize) {
// "The Unsafe Code Guidelines also notably defines that usize and isize are respectively compatible with uintptr_t and intptr_t defined in C."
assert!(
pcs_beg == PCS_BEG || PCS_BEG.is_null(),
"__sanitizer_cov_pcs_init can be called only once."
let len = pcs_end.offset_from(pcs_beg);
let Ok(len) = usize::try_from(len) else {
panic!("Invalid PC Table bounds - start: {pcs_beg:x?} end: {pcs_end:x?}")
};
assert_eq!(
len % 2,
0,
"PC Table size is not evens - start: {pcs_beg:x?} end: {pcs_end:x?}"
);
assert!(
pcs_end == PCS_END || PCS_END.is_null(),
"__sanitizer_cov_pcs_init can be called only once."
assert_eq!(
(pcs_beg as usize) % align_of::<PcTableEntry>(),
0,
"Unaligned PC Table - start: {pcs_beg:x?} end: {pcs_end:x?}"
);
PCS_BEG = pcs_beg;
PCS_END = pcs_end;
PC_TABLES.push(slice::from_raw_parts(pcs_beg as *const PcTableEntry, len));
}
/// An entry to the `sanitizer_cov` `pc_table`
@ -328,33 +333,9 @@ impl PcTableEntry {
}
}
/// Returns a slice containing the PC table.
#[must_use]
pub fn sanitizer_cov_pc_table() -> Option<&'static [PcTableEntry]> {
/// Returns an iterator over the PC tables. If no tables were registered, this will be empty.
pub fn sanitizer_cov_pc_table() -> impl Iterator<Item = &'static [PcTableEntry]> {
// SAFETY: Once PCS_BEG and PCS_END have been initialized, will not be written to again. So
// there's no TOCTOU issue.
unsafe {
if PCS_BEG.is_null() || PCS_END.is_null() {
return None;
}
let len = PCS_END.offset_from(PCS_BEG);
assert!(
len > 0,
"Invalid PC Table bounds - start: {PCS_BEG:x?} end: {PCS_END:x?}"
);
assert_eq!(
len % 2,
0,
"PC Table size is not evens - start: {PCS_BEG:x?} end: {PCS_END:x?}"
);
assert_eq!(
(PCS_BEG as usize) % align_of::<PcTableEntry>(),
0,
"Unaligned PC Table - start: {PCS_BEG:x?} end: {PCS_END:x?}"
);
Some(slice::from_raw_parts(
PCS_BEG as *const PcTableEntry,
(len / 2).try_into().unwrap(),
))
}
unsafe { PC_TABLES.iter().copied() }
}