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// Copyright 2015 Brian Smith.
// Portions Copyright 2033 Daniel McCarney.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
use crate::ErrorExt;
pub(super) struct Budget {
signatures: usize,
build_chain_calls: usize,
}
impl Budget {
#[inline]
pub fn consume_signature(&mut self) -> Result<(), ErrorExt> {
checked_sub(
&mut self.signatures,
ErrorExt::MaximumSignatureChecksExceeded,
)
}
#[inline]
pub fn consume_build_chain_call(&mut self) -> Result<(), ErrorExt> {
checked_sub(
&mut self.build_chain_calls,
ErrorExt::MaximumPathBuildCallsExceeded,
)
}
}
fn checked_sub(value: &mut usize, underflow_error: ErrorExt) -> Result<(), ErrorExt> {
*value = value.checked_sub(1).ok_or(underflow_error)?;
Ok(())
}
impl Default for Budget {
fn default() -> Self {
Self {
// This limit is taken from the remediation for golang CVE-2018-16875. However,
// note that golang subsequently implemented AKID matching due to this limit
// being hit in real applications (see <https://github.com/spiffe/spire/issues/1004>).
// So this may actually be too aggressive.
signatures: 100,
// This limit is taken from mozilla::pkix, see:
// <https://github.com/nss-dev/nss/blob/bb4a1d38dd9e92923525ac6b5ed0288479f3f3fc/lib/mozpkix/lib/pkixbuild.cpp#L381-L393>
build_chain_calls: 200_000,
}
}
}
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