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Check argument pointers for null to WASI calls

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This commit is contained in:
Mark McCaskey
2019-10-03 10:50:07 -07:00
parent b45b1c12f1
commit 70b55b801d
4 changed files with 32 additions and 9 deletions
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16
lib/runtime-c-api/src/import.rs
View File

@ -54,6 +54,7 @@ pub unsafe extern "C" fn wasmer_import_object_new() -> *mut wasmer_import_object
#[cfg(feature = "wasi")]
mod wasi {
use super::*;
use crate::get_slice_checked;
use std::path::PathBuf;
/// Opens a directory that's visible to the WASI module as `alias` but
@ -76,7 +77,11 @@ mod wasi {
}
}
/// Creates a WASI import object
/// Creates a WASI import object.
///
/// This function treats null pointers as empty collections.
/// For example, passing null for a string in `args`, will lead to a zero
/// length argument in that position.
#[no_mangle]
pub unsafe extern "C" fn wasmer_wasi_generate_import_object(
args: *const wasmer_byte_array,
@ -88,11 +93,10 @@ mod wasi {
mapped_dirs: *const wasmer_wasi_map_dir_entry_t,
mapped_dirs_len: c_uint,
) -> *mut wasmer_import_object_t {
let arg_list = std::slice::from_raw_parts(args, args_len as usize);
let env_list = std::slice::from_raw_parts(envs, envs_len as usize);
let preopened_file_list =
std::slice::from_raw_parts(preopened_files, preopened_files_len as usize);
let mapped_dir_list = std::slice::from_raw_parts(mapped_dirs, mapped_dirs_len as usize);
let arg_list = get_slice_checked(args, args_len as usize);
let env_list = get_slice_checked(envs, envs_len as usize);
let preopened_file_list = get_slice_checked(preopened_files, preopened_files_len as usize);
let mapped_dir_list = get_slice_checked(mapped_dirs, mapped_dirs_len as usize);
wasmer_wasi_generate_import_object_inner(
arg_list,

13
lib/runtime-c-api/src/lib.rs
View File

@ -133,7 +133,7 @@ pub struct wasmer_byte_array {
impl wasmer_byte_array {
/// Get the data as a slice
pub unsafe fn as_slice<'a>(&self) -> &'a [u8] {
std::slice::from_raw_parts(self.bytes, self.bytes_len as usize)
get_slice_checked(self.bytes, self.bytes_len as usize)
}
/// Copy the data into an owned Vec
@ -149,3 +149,14 @@ impl wasmer_byte_array {
std::str::from_utf8(self.as_slice())
}
}
/// Gets a slice from a pointer and a length, returning an empty slice if the
/// pointer is null
#[inline]
pub(crate) unsafe fn get_slice_checked<'a, T>(ptr: *const T, len: usize) -> &'a [T] {
if ptr.is_null() {
&[]
} else {
std::slice::from_raw_parts(ptr, len)
}
}

6
lib/runtime-c-api/wasmer.h
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@ -781,7 +781,11 @@ bool wasmer_validate(const uint8_t *wasm_bytes, uint32_t wasm_bytes_len);
wasmer_import_object_t *wasmer_wasi_generate_default_import_object(void);
/**
* Creates a WASI import object
* Creates a WASI import object.
*
* This function treats null pointers as empty collections.
* For example, passing null for a string in `args`, will lead to a zero
* length argument in that position.
*/
wasmer_import_object_t *wasmer_wasi_generate_import_object(const wasmer_byte_array *args,
unsigned int args_len,

6
lib/runtime-c-api/wasmer.hh
View File

@ -606,7 +606,11 @@ bool wasmer_validate(const uint8_t *wasm_bytes, uint32_t wasm_bytes_len);
/// empty values.
wasmer_import_object_t *wasmer_wasi_generate_default_import_object();
/// Creates a WASI import object
/// Creates a WASI import object.
///
/// This function treats null pointers as empty collections.
/// For example, passing null for a string in `args`, will lead to a zero
/// length argument in that position.
wasmer_import_object_t *wasmer_wasi_generate_import_object(const wasmer_byte_array *args,
unsigned int args_len,
const wasmer_byte_array *envs,