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sys_util: use checked arithmetic and alignment in sock_ctrl_msg

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Change-Id: I45125fc3a6af83e7f7ec791a2f9c5daef723ec89
Reviewed-on: https://chromium-review.googlesource.com/1277872
Commit-Ready: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
This commit is contained in:
Zach Reizner 2018-10-11 13:43:41 -07:00 committed by chrome-bot
parent c7af4b1e68
commit 029fc665a1
1 changed files with 24 additions and 11 deletions
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35
sys_util/src/sock_ctrl_msg.rs
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@ -45,15 +45,17 @@ macro_rules! CMSG_LEN {
// module supports.
#[allow(non_snake_case)]
#[inline(always)]
fn CMSG_DATA(cmsg_buffer: *mut u8) -> *mut RawFd {
fn CMSG_DATA(cmsg_buffer: *mut cmsghdr) -> *mut RawFd {
// Essentially returns a pointer to just past the header.
(cmsg_buffer as *mut cmsghdr).wrapping_offset(1) as *mut RawFd
cmsg_buffer.wrapping_offset(1) as *mut RawFd
}
// This function is like CMSG_NEXT, but safer because it reads only from references, although it
// does some pointer arithmetic on cmsg_ptr.
fn get_next_cmsg(msghdr: &msghdr, cmsg: &cmsghdr, cmsg_ptr: *mut u8) -> *mut u8 {
let next_cmsg = cmsg_ptr.wrapping_offset(CMSG_ALIGN!(cmsg.cmsg_len) as isize);
#[cfg_attr(feature = "cargo-clippy", allow(cast_ptr_alignment))]
fn get_next_cmsg(msghdr: &msghdr, cmsg: &cmsghdr, cmsg_ptr: *mut cmsghdr) -> *mut cmsghdr {
let next_cmsg =
(cmsg_ptr as *mut u8).wrapping_offset(CMSG_ALIGN!(cmsg.cmsg_len) as isize) as *mut cmsghdr;
if next_cmsg
.wrapping_offset(1)
.wrapping_sub(msghdr.msg_control as usize) as usize
@ -68,22 +70,33 @@ fn get_next_cmsg(msghdr: &msghdr, cmsg: &cmsghdr, cmsg_ptr: *mut u8) -> *mut u8
const CMSG_BUFFER_INLINE_CAPACITY: usize = CMSG_SPACE!(size_of::<RawFd>() * 32);
enum CmsgBuffer {
Inline([u8; CMSG_BUFFER_INLINE_CAPACITY]),
Heap(Box<[u8]>),
Inline([u64; (CMSG_BUFFER_INLINE_CAPACITY + 7) / 8]),
Heap(Box<[cmsghdr]>),
}
impl CmsgBuffer {
fn with_capacity(capacity: usize) -> CmsgBuffer {
let cap_in_cmsghdr_units =
(capacity.checked_add(size_of::<cmsghdr>()).unwrap() - 1) / size_of::<cmsghdr>();
if capacity <= CMSG_BUFFER_INLINE_CAPACITY {
CmsgBuffer::Inline([0u8; CMSG_BUFFER_INLINE_CAPACITY])
CmsgBuffer::Inline([0u64; (CMSG_BUFFER_INLINE_CAPACITY + 7) / 8])
} else {
CmsgBuffer::Heap(vec![0; capacity].into_boxed_slice())
CmsgBuffer::Heap(
vec![
cmsghdr {
cmsg_len: 0,
cmsg_level: 0,
cmsg_type: 0,
};
cap_in_cmsghdr_units
].into_boxed_slice(),
)
}
}
fn as_mut_ptr(&mut self) -> *mut u8 {
fn as_mut_ptr(&mut self) -> *mut cmsghdr {
match self {
CmsgBuffer::Inline(a) => a.as_mut_ptr(),
CmsgBuffer::Inline(a) => a.as_mut_ptr() as *mut cmsghdr,
CmsgBuffer::Heap(a) => a.as_mut_ptr(),
}
}
@ -177,7 +190,7 @@ fn raw_recvmsg(fd: RawFd, in_data: &mut [u8], in_fds: &mut [RawFd]) -> Result<(u
return Ok((0, 0));
}
let mut cmsg_ptr = msg.msg_control as *mut u8;
let mut cmsg_ptr = msg.msg_control as *mut cmsghdr;
let mut in_fds_count = 0;
while !cmsg_ptr.is_null() {
// Safe because we checked that cmsg_ptr was non-null, and the loop is constructed such that