btls 0.5.6

BoringSSL bindings
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96

use crate::error::ErrorStack;
use foreign_types::{ForeignType, ForeignTypeRef};
use libc::{c_char, c_int, c_void};
use std::any::Any;
use std::panic::{self, AssertUnwindSafe};
use std::slice;

/// Wraps a user-supplied callback and a slot for panics thrown inside the callback (while FFI
/// frames are on the stack).
///
/// When dropped, checks if the callback has panicked, and resumes unwinding if so.
pub struct CallbackState<F> {
    /// The user callback. Taken out of the `Option` when called.
    cb: Option<F>,
    /// If the callback panics, we place the panic object here, to be re-thrown once OpenSSL
    /// returns.
    panic: Option<Box<dyn Any + Send + 'static>>,
}

impl<F> CallbackState<F> {
    pub fn new(callback: F) -> Self {
        CallbackState {
            cb: Some(callback),
            panic: None,
        }
    }
}

impl<F> Drop for CallbackState<F> {
    fn drop(&mut self) {
        if let Some(panic) = self.panic.take() {
            panic::resume_unwind(panic);
        }
    }
}

/// Password callback function, passed to private key loading functions.
///
/// `cb_state` is expected to be a pointer to a `CallbackState`.
pub unsafe extern "C" fn invoke_passwd_cb<F>(
    buf: *mut c_char,
    size: c_int,
    _rwflag: c_int,
    cb_state: *mut c_void,
) -> c_int
where
    F: FnOnce(&mut [u8]) -> Result<usize, ErrorStack>,
{
    unsafe {
        let callback = &mut *cb_state.cast::<CallbackState<F>>();

        let result = panic::catch_unwind(AssertUnwindSafe(|| {
            let pass_slice = slice::from_raw_parts_mut(buf.cast::<u8>(), size as usize);
            callback.cb.take().unwrap()(pass_slice)
        }));

        match result {
            Ok(Ok(len)) => len as c_int,
            Ok(Err(err)) => {
                err.put();
                0
            }
            Err(err) => {
                callback.panic = Some(err);
                0
            }
        }
    }
}

#[allow(dead_code)]
pub trait ForeignTypeExt: ForeignType {
    unsafe fn from_ptr_opt(ptr: *mut Self::CType) -> Option<Self> {
        if ptr.is_null() {
            None
        } else {
            Some(unsafe { Self::from_ptr(ptr) })
        }
    }
}
impl<FT: ForeignType> ForeignTypeExt for FT {}

pub trait ForeignTypeRefExt: ForeignTypeRef {
    unsafe fn from_const_ptr<'a>(ptr: *const Self::CType) -> &'a Self {
        unsafe { Self::from_ptr(ptr.cast_mut()) }
    }

    unsafe fn from_const_ptr_opt<'a>(ptr: *const Self::CType) -> Option<&'a Self> {
        if ptr.is_null() {
            None
        } else {
            Some(unsafe { Self::from_const_ptr(ptr.cast_mut()) })
        }
    }
}
impl<FT: ForeignTypeRef> ForeignTypeRefExt for FT {}