* [OE-core][wrynose][patch 1/2] python3-cryptography: Fix CVE-2026-69248 @ 2026-09-11 14:18 Vijay Anusuri 2026-09-11 14:18 ` [OE-core][wrynose][patch 2/2] python3-cryptography: Fix CVE-2026-69249 Vijay Anusuri 0 siblings, 1 reply; 2+ messages in thread From: Vijay Anusuri @ 2026-09-11 14:18 UTC (permalink / raw) To: openembedded-core; +Cc: Vijay Anusuri Pick patch according to [2] [1] https://nvd.nist.gov/vuln/detail/cve-2026-69248 [2] https://security-tracker.debian.org/tracker/CVE-2026-69248 Signed-off-by: Vijay Anusuri <vanusuri@mvista.com> --- .../python/python3-cryptography.bb | 1 + .../python3-cryptography/CVE-2026-69248.patch | 302 ++++++++++++++++++ 2 files changed, 303 insertions(+) create mode 100644 meta/recipes-devtools/python/python3-cryptography/CVE-2026-69248.patch diff --git a/meta/recipes-devtools/python/python3-cryptography.bb b/meta/recipes-devtools/python/python3-cryptography.bb index c6561deb3c..5c1de9192b 100644 --- a/meta/recipes-devtools/python/python3-cryptography.bb +++ b/meta/recipes-devtools/python/python3-cryptography.bb @@ -15,6 +15,7 @@ SRC_URI[sha256sum] = "e4cfd68c5f3e0bfdad0d38e023239b96a2fe84146481852dffbcca442c SRC_URI += "file://0001-pyproject.toml-remove-benchmark-disable-option.patch \ file://0002-Fix-installing-stray-files-into-site-packages.patch \ + file://CVE-2026-69248.patch \ file://check-memfree.py \ file://run-ptest \ " diff --git a/meta/recipes-devtools/python/python3-cryptography/CVE-2026-69248.patch b/meta/recipes-devtools/python/python3-cryptography/CVE-2026-69248.patch new file mode 100644 index 0000000000..66cfa12a6c --- /dev/null +++ b/meta/recipes-devtools/python/python3-cryptography/CVE-2026-69248.patch @@ -0,0 +1,302 @@ +From 4d035a4225965edeffd312079a510ef25fcfdcb2 Mon Sep 17 00:00:00 2001 +From: William Woodruff <william@yossarian.net> +Date: Thu, 21 May 2026 20:44:05 -0400 +Subject: [PATCH] x509: distinguish NC kinds when evaluating wildcard DNS SANs + (#14888) + +* x509: distinguish NC kinds when evaluating wildcard DNS SANs + +* Bump x509-limbo + +Upstream-Status: Backport [https://github.com/pyca/cryptography/commit/4d035a4225965edeffd312079a510ef25fcfdcb2] +CVE: CVE-2026-69248 +Signed-off-by: Vijay Anusuri <vanusuri@mvista.com> +--- + .../cryptography-x509-verification/src/lib.rs | 43 ++++- + .../src/types.rs | 165 ++++++++++++------ + 2 files changed, 145 insertions(+), 63 deletions(-) + +diff --git a/src/rust/cryptography-x509-verification/src/lib.rs b/src/rust/cryptography-x509-verification/src/lib.rs +index c59f84f..60c89d4 100644 +--- a/src/rust/cryptography-x509-verification/src/lib.rs ++++ b/src/rust/cryptography-x509-verification/src/lib.rs +@@ -147,6 +147,7 @@ impl<'a, 'chain> NameChain<'a, 'chain> { + + fn evaluate_single_constraint<B: CryptoOps>( + &self, ++ kind: SubtreeKind, + constraint: &GeneralName<'chain>, + san: &GeneralName<'chain>, + budget: &mut Budget, +@@ -155,14 +156,18 @@ impl<'a, 'chain> NameChain<'a, 'chain> { + + match (constraint, san) { + (GeneralName::DNSName(constraint), GeneralName::DNSName(name)) => { +- // NOTE: A DNS SAN can be a wildcard pattern instead of a normal DNS name. +- // These are handled by matching unconditionally on the inner name, +- // since a NC of `foo.com` will match both `foo.com` and any arbitrarily deep +- // subdomain of `foo.com`, where a wildcard SAN like `*.foo.com` will only +- // match exactly one subdomain of `foo.com`. Therefore, the NC's matching +- // set is a strict superset of any possible wildcard SAN pattern. ++ // NOTE: A DNS SAN can be a wildcard pattern (e.g. `*.foo.com`) ++ // rather than an ordinary DNS name. A wildcard represents a ++ // *set* of names, so the check depends on which subtree we're ++ // evaluating: a `permittedSubtrees` constraint must contain ++ // *every* name the wildcard can expand to, whereas an ++ // `excludedSubtrees` constraint matches if it overlaps the ++ // wildcard at all. We dispatch on `kind` accordingly. + match (DNSConstraint::new(constraint.0), DNSPattern::new(name.0)) { +- (Some(constraint), Some(name)) => Ok(Applied(constraint.matches(&name))), ++ (Some(constraint), Some(name)) => Ok(Applied(match kind { ++ SubtreeKind::Permitted => constraint.permits(&name), ++ SubtreeKind::Excluded => constraint.excludes(&name), ++ })), + (_, None) => Err(ValidationError::new(ValidationErrorKind::Other(format!( + "unsatisfiable DNS name constraint: malformed SAN {}", + name.0 +@@ -232,7 +237,12 @@ impl<'a, 'chain> NameChain<'a, 'chain> { + let mut permit = true; + if let Some(permitted_subtrees) = &constraints.permitted_subtrees { + for p in permitted_subtrees.clone() { +- let status = self.evaluate_single_constraint(&p.base, &san, budget)?; ++ let status = self.evaluate_single_constraint( ++ SubtreeKind::Permitted, ++ &p.base, ++ &san, ++ budget, ++ )?; + if status.is_applied() { + permit = status.is_match(); + if permit { +@@ -250,7 +260,12 @@ impl<'a, 'chain> NameChain<'a, 'chain> { + + if let Some(excluded_subtrees) = &constraints.excluded_subtrees { + for e in excluded_subtrees.clone() { +- let status = self.evaluate_single_constraint(&e.base, &san, budget)?; ++ let status = self.evaluate_single_constraint( ++ SubtreeKind::Excluded, ++ &e.base, ++ &san, ++ budget, ++ )?; + if status.is_match() { + return Err(ValidationError::new(ValidationErrorKind::Other( + "excluded name constraint matched SAN".into(), +@@ -284,6 +299,16 @@ struct ChainBuilder<'a, 'chain, B: CryptoOps> { + store: &'a Store<'chain, B>, + } + ++/// Identifies which kind of name constraint subtree a SAN is being evaluated ++/// against. The two subtree kinds use different matching semantics for ++/// wildcard DNS SANs (containment vs. overlap); see [`DNSConstraint::permits`] ++/// and [`DNSConstraint::excludes`]. ++#[derive(Clone, Copy)] ++enum SubtreeKind { ++ Permitted, ++ Excluded, ++} ++ + // When applying a name constraint, we need to distinguish between a few different scenarios: + // * `Applied(true)`: The name constraint is the same type as the SAN and matches. + // * `Applied(false)`: The name constraint is the same type as the SAN and does not match. +diff --git a/src/rust/cryptography-x509-verification/src/types.rs b/src/rust/cryptography-x509-verification/src/types.rs +index 86316f4..0ec0be2 100644 +--- a/src/rust/cryptography-x509-verification/src/types.rs ++++ b/src/rust/cryptography-x509-verification/src/types.rs +@@ -150,44 +150,69 @@ impl<'a> DNSConstraint<'a> { + DNSName::new(pattern).map(Self) + } + +- /// Returns true if this `DNSConstraint` matches the given `DNSPattern`. ++ /// Returns true if the given exact `DNSName` falls within this ++ /// constraint's subtree. + /// +- /// Constraint matching is defined by RFC 5280: any DNS name that can +- /// be constructed by simply adding zero or more labels to the left-hand +- /// side of the name satisfies the name constraint. ++ /// Per RFC 5280, a name satisfies the constraint if it can be constructed ++ /// by adding zero or more labels to the left-hand side of the constraint's ++ /// name (i.e. it is the constraint's name, or a subdomain of it). ++ fn contains(&self, name: &DNSName<'_>) -> bool { ++ // NOTE: This may seem like an obtuse way to perform label matching, ++ // but it saves us a few allocations: doing a substring check instead ++ // would require us to clone each string and do case normalization. ++ // Note also that we check the length in advance: Rust's zip ++ // implementation terminates with the shorter iterator, so we need ++ // to first check that the candidate name is at least as long as ++ // the constraint it's matching against. ++ name.as_str().len() >= self.0.as_str().len() ++ && self ++ .0 ++ .rlabels() ++ .zip(name.rlabels()) ++ .all(|(a, o)| a.eq_ignore_ascii_case(o)) ++ } ++ ++ /// Returns true if the given `DNSPattern` is permitted by this constraint, ++ /// for use with a `permittedSubtrees` name constraint. + /// +- /// On top of what RFC 5280 specifies, we define behavior for wildcard +- /// patterns (which are not covered by RFC 5280): a wildcard pattern +- /// matches a constraint if the pattern matches the constraint's inner name, +- /// _or_ if the pattern's inner name matches the constraint. +- /// This allows us to reject DNS names like `*.example.com` when +- /// the constraint is `example.com` or `bar.example.com`. +- pub fn matches(&self, name: &DNSPattern<'_>) -> bool { +- match name { +- DNSPattern::Exact(name) => { +- // NOTE: This may seem like an obtuse way to perform label matching, +- // but it saves us a few allocations: doing a substring check instead +- // would require us to clone each string and do case normalization. +- // Note also that we check the length in advance: Rust's zip +- // implementation terminates with the shorter iterator, so we need +- // to first check that the candidate name is at least as long as +- // the constraint it's matching against. +- name.as_str().len() >= self.0.as_str().len() +- && self +- .0 +- .rlabels() +- .zip(name.rlabels()) +- .all(|(a, o)| a.eq_ignore_ascii_case(o)) +- } +- DNSPattern::Wildcard(inner) => { +- // NOTE: This check is not as simple as a single pattern match, +- // since we need two subtly distinct cases here: +- // 1. Constraint `bar.example.com` on `*.example.com` +- // 2. Constraint `example.com` on `*.example.com` +- // The first cases is handled by `DNSPattern::matches`, and the second is handled +- // by `DNSConstraint::matches`. +- name.matches(&self.0) || self.matches(&DNSPattern::Exact(inner.clone())) +- } ++ /// A pattern is permitted only if *every* name it can represent falls ++ /// within the constraint's subtree. An exact name is permitted by ordinary ++ /// subtree containment (per RFC 5280). ++ /// ++ /// Wildcard patterns are not covered by RFC 5280; we define their behavior ++ /// here. A wildcard pattern `*.X` is permitted only if its base name `X` ++ /// itself falls within the constraint's subtree. This is stricter than ++ /// mere overlap: `*.example.com` is *not* permitted by `foo.example.com`, ++ /// since it can also expand to a sibling such as `bar.example.com` that ++ /// lies outside the permitted subtree. ++ pub fn permits(&self, pattern: &DNSPattern<'_>) -> bool { ++ match pattern { ++ DNSPattern::Exact(name) => self.contains(name), ++ DNSPattern::Wildcard(base) => self.contains(base), ++ } ++ } ++ ++ /// Returns true if the given `DNSPattern` is excluded by this constraint, ++ /// for use with an `excludedSubtrees` name constraint. ++ /// ++ /// A pattern is excluded if *any* name it can represent falls within the ++ /// constraint's subtree. An exact name is excluded by ordinary subtree ++ /// containment (per RFC 5280). ++ /// ++ /// Wildcard patterns are not covered by RFC 5280; we define their behavior ++ /// here. A wildcard pattern `*.X` is excluded if it overlaps the subtree ++ /// at all, which happens in two subtly distinct cases: ++ /// ++ /// 1. The constraint is more specific than the wildcard, e.g. constraint ++ /// `bar.example.com` and pattern `*.example.com` (which can expand to ++ /// `bar.example.com`). This is handled by `DNSPattern::matches`. ++ /// 2. The wildcard's base name falls within the subtree, e.g. constraint ++ /// `example.com` and pattern `*.example.com`. This is handled by ++ /// `DNSConstraint::contains`. ++ pub fn excludes(&self, pattern: &DNSPattern<'_>) -> bool { ++ match pattern { ++ DNSPattern::Exact(name) => self.contains(name), ++ DNSPattern::Wildcard(base) => pattern.matches(&self.0) || self.contains(base), + } + } + } +@@ -590,37 +615,69 @@ mod tests { + } + + #[test] +- fn test_dnsconstraint_matches() { ++ fn test_dnsconstraint_exact() { + let example_com = DNSConstraint::new("example.com").unwrap(); + +- // Exact domain and arbitrary subdomains match. +- assert!(example_com.matches(&DNSPattern::new("example.com").unwrap())); +- assert!(example_com.matches(&DNSPattern::new("foo.example.com").unwrap())); +- assert!(example_com.matches(&DNSPattern::new("foo.bar.baz.quux.example.com").unwrap())); ++ // For exact patterns, `permits` and `excludes` behave identically: ++ // the pattern must fall within the constraint's subtree. ++ for permitted in [ ++ "example.com", ++ "foo.example.com", ++ "foo.bar.baz.quux.example.com", ++ ] { ++ let pattern = DNSPattern::new(permitted).unwrap(); ++ assert!(example_com.permits(&pattern)); ++ assert!(example_com.excludes(&pattern)); ++ } + + // Parent domains, distinct domains, and substring domains do not match. +- assert!(!example_com.matches(&DNSPattern::new("com").unwrap())); +- assert!(!example_com.matches(&DNSPattern::new("badexample.com").unwrap())); +- assert!(!example_com.matches(&DNSPattern::new("wrong.com").unwrap())); ++ for rejected in ["com", "badexample.com", "wrong.com"] { ++ let pattern = DNSPattern::new(rejected).unwrap(); ++ assert!(!example_com.permits(&pattern)); ++ assert!(!example_com.excludes(&pattern)); ++ } + } + + #[test] +- fn test_dnsconstraint_matches_wildcard() { ++ fn test_dnsconstraint_permits_wildcard() { ++ let com = DNSConstraint::new("com").unwrap(); ++ let example_com = DNSConstraint::new("example.com").unwrap(); ++ let foo_example_com = DNSConstraint::new("foo.example.com").unwrap(); ++ let any_example_com = DNSPattern::new("*.example.com").unwrap(); ++ ++ // A wildcard `*.example.com` is permitted only by constraints whose ++ // subtree contains *every* name the wildcard can expand to, i.e. those ++ // that contain `example.com` itself. ++ assert!(com.permits(&any_example_com)); ++ assert!(example_com.permits(&any_example_com)); ++ ++ // A constraint more specific than the wildcard's base does *not* ++ // permit it: the wildcard can expand to siblings outside the subtree ++ // (e.g. `*.example.com` can be `bar.example.com`, which lies outside ++ // `foo.example.com`). ++ assert!(!foo_example_com.permits(&any_example_com)); ++ } ++ ++ #[test] ++ fn test_dnsconstraint_excludes_wildcard() { + let com = DNSConstraint::new("com").unwrap(); + let example_com = DNSConstraint::new("example.com").unwrap(); + let bar_example_com = DNSConstraint::new("bar.example.com").unwrap(); + let baz_bar_example_com = DNSConstraint::new("baz.bar.example.com").unwrap(); + let any_example_com = DNSPattern::new("*.example.com").unwrap(); + +- assert!(com.matches(&any_example_com)); +- assert!(example_com.matches(&any_example_com)); +- assert!(bar_example_com.matches(&any_example_com)); +- +- // A constraint on `baz.bar.example.com` doesn't match `*.example.com`, +- // since `baz.bar.example.com` matches zero or more sublabels of +- // `baz.bar.example.com` while `*.example.com` matches exactly one +- // sublabel of `example.com`. +- assert!(!baz_bar_example_com.matches(&any_example_com)); ++ // A wildcard `*.example.com` is excluded by any constraint whose ++ // subtree it overlaps, including constraints more specific than the ++ // wildcard's base. ++ assert!(com.excludes(&any_example_com)); ++ assert!(example_com.excludes(&any_example_com)); ++ assert!(bar_example_com.excludes(&any_example_com)); ++ ++ // A constraint on `baz.bar.example.com` doesn't overlap ++ // `*.example.com`, since `baz.bar.example.com` matches zero or more ++ // sublabels of `baz.bar.example.com` while `*.example.com` matches ++ // exactly one sublabel of `example.com`. ++ assert!(!baz_bar_example_com.excludes(&any_example_com)); + } + + #[test] +-- +2.43.0 + -- 2.43.0 ^ permalink raw reply related [flat|nested] 2+ messages in thread
* [OE-core][wrynose][patch 2/2] python3-cryptography: Fix CVE-2026-69249 2026-09-11 14:18 [OE-core][wrynose][patch 1/2] python3-cryptography: Fix CVE-2026-69248 Vijay Anusuri @ 2026-09-11 14:18 ` Vijay Anusuri 0 siblings, 0 replies; 2+ messages in thread From: Vijay Anusuri @ 2026-09-11 14:18 UTC (permalink / raw) To: openembedded-core; +Cc: Vijay Anusuri Pick patch according to [2] [1] https://nvd.nist.gov/vuln/detail/cve-2026-69249 [2] https://security-tracker.debian.org/tracker/CVE-2026-69249 Signed-off-by: Vijay Anusuri <vanusuri@mvista.com> --- .../python/python3-cryptography.bb | 1 + .../python3-cryptography/CVE-2026-69249.patch | 338 ++++++++++++++++++ 2 files changed, 339 insertions(+) create mode 100644 meta/recipes-devtools/python/python3-cryptography/CVE-2026-69249.patch diff --git a/meta/recipes-devtools/python/python3-cryptography.bb b/meta/recipes-devtools/python/python3-cryptography.bb index 5c1de9192b..f3cb755ed5 100644 --- a/meta/recipes-devtools/python/python3-cryptography.bb +++ b/meta/recipes-devtools/python/python3-cryptography.bb @@ -16,6 +16,7 @@ SRC_URI[sha256sum] = "e4cfd68c5f3e0bfdad0d38e023239b96a2fe84146481852dffbcca442c SRC_URI += "file://0001-pyproject.toml-remove-benchmark-disable-option.patch \ file://0002-Fix-installing-stray-files-into-site-packages.patch \ file://CVE-2026-69248.patch \ + file://CVE-2026-69249.patch \ file://check-memfree.py \ file://run-ptest \ " diff --git a/meta/recipes-devtools/python/python3-cryptography/CVE-2026-69249.patch b/meta/recipes-devtools/python/python3-cryptography/CVE-2026-69249.patch new file mode 100644 index 0000000000..f700d3f1ee --- /dev/null +++ b/meta/recipes-devtools/python/python3-cryptography/CVE-2026-69249.patch @@ -0,0 +1,338 @@ +From 4a12cf49675a184e47f912b00b04f3a629283582 Mon Sep 17 00:00:00 2001 +From: William Woodruff <william@yossarian.net> +Date: Sat, 6 Jun 2026 23:30:03 -0400 +Subject: [PATCH] Add a signature validation budget during path construction + (#14960) + +* Add a signature validation budget during path construction + +This extends our existing NC budget check to include a budget +for signature validations. If a path construction exceeds the +budget by performing more than the allowed number of signature +validation steps, the entire construction fails. + +For now, our budget is 128 signature validations. This is +consistent with (higher than) Go and rustls-webpki, which +both set a limit of 100. Like Go, we attempt to make the "best" +use of our signature budget by ordering by likelihood, using +AKI/SKI match as the strongest signal of fitness. + +* Bump limbo + +* Temporary commit + +* Revert "Temporary commit" + +This reverts commit bcdb6808562a8b8f484f85d21cb201cfdb2bbbd7. + +* Fudge a coverage test into place + +* Coverage for the coverage god + +Upstream-Status: Backport [https://github.com/pyca/cryptography/commit/4a12cf49675a184e47f912b00b04f3a629283582] +CVE: CVE-2026-69249 +Signed-off-by: Vijay Anusuri <vanusuri@mvista.com> +--- + .../cryptography-x509-verification/src/lib.rs | 183 +++++++++++++++++- + .../src/policy/mod.rs | 9 +- + 2 files changed, 182 insertions(+), 10 deletions(-) + +diff --git a/src/rust/cryptography-x509-verification/src/lib.rs b/src/rust/cryptography-x509-verification/src/lib.rs +index 60c89d4..7ee3bb0 100644 +--- a/src/rust/cryptography-x509-verification/src/lib.rs ++++ b/src/rust/cryptography-x509-verification/src/lib.rs +@@ -18,10 +18,14 @@ use std::vec; + use asn1::ObjectIdentifier; + use cryptography_x509::common::Asn1Read; + use cryptography_x509::extensions::{ +- DuplicateExtensionsError, Extensions, NameConstraints, SubjectAlternativeName, ++ AuthorityKeyIdentifier, DuplicateExtensionsError, Extensions, NameConstraints, ++ SubjectAlternativeName, + }; + use cryptography_x509::name::GeneralName; +-use cryptography_x509::oid::{NAME_CONSTRAINTS_OID, SUBJECT_ALTERNATIVE_NAME_OID}; ++use cryptography_x509::oid::{ ++ AUTHORITY_KEY_IDENTIFIER_OID, NAME_CONSTRAINTS_OID, SUBJECT_ALTERNATIVE_NAME_OID, ++ SUBJECT_KEY_IDENTIFIER_OID, ++}; + + use crate::certificate::cert_is_self_issued; + use crate::ops::{CryptoOps, VerificationCertificate}; +@@ -98,15 +102,23 @@ impl<B: CryptoOps> Display for ValidationError<'_, B> { + + struct Budget { + name_constraint_checks: usize, ++ signature_checks: usize, + } + + impl Budget { +- // Same limit as other validators ++ // The maximum number of name constraint checks performed when attempting ++ // path construction. This is the same limit as other validators. + const DEFAULT_NAME_CONSTRAINT_CHECK_LIMIT: usize = 1 << 20; + ++ // The maximum number of signature verifications performed when attempting ++ // path construction. The is similar to other validators: ++ // both Go and rustls-webpki pick 100. ++ const DEFAULT_SIGNATURE_CHECK_LIMIT: usize = 1 << 7; ++ + fn new() -> Budget { + Budget { + name_constraint_checks: Self::DEFAULT_NAME_CONSTRAINT_CHECK_LIMIT, ++ signature_checks: Self::DEFAULT_SIGNATURE_CHECK_LIMIT, + } + } + +@@ -119,6 +131,15 @@ impl Budget { + })?; + Ok(()) + } ++ ++ fn signature_check<'chain, B: CryptoOps>(&mut self) -> ValidationResult<'chain, (), B> { ++ self.signature_checks = self.signature_checks.checked_sub(1).ok_or_else(|| { ++ ValidationError::new(ValidationErrorKind::FatalError( ++ "Exceeded maximum signature check limit", ++ )) ++ })?; ++ Ok(()) ++ } + } + + struct NameChain<'a, 'chain> { +@@ -341,18 +362,57 @@ impl<'a, 'chain, B: CryptoOps> ChainBuilder<'a, 'chain, B> { + } + } + ++ /// Identify and return potential issuers for `cert`, considering ++ /// candidates from both the trusted store and untrusted intermediate set. ++ /// Trusted candidates are returned before untrusted intermediate ++ /// candidates, and both groups are opportunisitically ordered by ++ /// "likeliness" in terms of AKI/SKI match. + fn potential_issuers( + &self, + cert: &'a VerificationCertificate<'chain, B>, +- ) -> impl Iterator<Item = &'a VerificationCertificate<'chain, B>> + '_ { +- // TODO: Optimizations: +- // * Search by AKI and other identifiers? +- self.store ++ cert_extensions: &Extensions<'chain>, ++ ) -> Vec<&'a VerificationCertificate<'chain, B>> { ++ let mut candidates: Vec<&'a VerificationCertificate<'chain, B>> = self ++ .store + .get_by_subject(&cert.certificate().tbs_cert.issuer) + .iter() + .chain(self.intermediates.iter().filter(|&candidate| { + candidate.certificate().subject() == cert.certificate().issuer() + })) ++ .collect(); ++ ++ let want_kid: Option<&[u8]> = cert_extensions ++ .get_extension(&AUTHORITY_KEY_IDENTIFIER_OID) ++ .and_then(|ext| ext.value::<AuthorityKeyIdentifier<'_, Asn1Read>>().ok()) ++ .and_then(|aki| aki.key_identifier); ++ ++ // This mirrors Go's `findPotentialParents`: we have a global ++ // signature budget, so we want to bucket candidates by likeliness ++ // to avoid wasting budget on (potentially adversarial) name collisions. ++ // ++ // Observe that we use a stable sort to preserve trusted candidates ++ // before untrusted candidates in each likeliness bucket. In other ++ // words, we always try a likely trusted candidate over an equally ++ // likely untrusted one. ++ // ++ // See: <https://github.com/golang/go/blob/d00c67f297e/src/crypto/x509/cert_pool.go#L136> ++ candidates.sort_by_key(|candidate| { ++ let have_kid: Option<&[u8]> = ++ candidate.certificate().extensions().ok().and_then(|exts| { ++ exts.get_extension(&SUBJECT_KEY_IDENTIFIER_OID) ++ .and_then(|ext| ext.value::<&[u8]>().ok()) ++ }); ++ ++ match (want_kid, have_kid) { ++ // cert AKID matches candidate SKID, highest likelihood. ++ (Some(want), Some(have)) if want == have => 0, ++ // cert AKID and candidate SKID don't match, lowest likelihood. ++ (Some(_), Some(_)) => 2, ++ // cert AKID and/or candidate SKID is not present, medium likelihood. ++ _ => 1u8, ++ } ++ }); ++ candidates + } + + fn build_chain_inner( +@@ -385,7 +445,8 @@ impl<'a, 'chain, B: CryptoOps> ChainBuilder<'a, 'chain, B> { + // Otherwise, we collect a list of potential issuers for this cert, + // and continue with the first that verifies. + let mut last_err: Option<ValidationError<'_, B>> = None; +- for issuing_cert_candidate in self.potential_issuers(working_cert) { ++ for issuing_cert_candidate in self.potential_issuers(working_cert, working_cert_extensions) ++ { + // A candidate issuer is said to verify if it both + // signs for the working certificate and conforms to the + // policy. +@@ -395,6 +456,7 @@ impl<'a, 'chain, B: CryptoOps> ChainBuilder<'a, 'chain, B> { + working_cert, + current_depth, + &issuer_extensions, ++ budget, + ) { + Ok(_) => { + match self.build_chain_inner( +@@ -503,10 +565,15 @@ impl<'a, 'chain, B: CryptoOps> ChainBuilder<'a, 'chain, B> { + #[cfg(test)] + mod tests { + use asn1::ParseError; ++ use cryptography_x509::certificate::Certificate; + use cryptography_x509::oid::SUBJECT_ALTERNATIVE_NAME_OID; + + use crate::certificate::tests::PublicKeyErrorOps; +- use crate::{ValidationError, ValidationErrorKind}; ++ use crate::ops::{CryptoOps, VerificationCertificate}; ++ use crate::policy::{Policy, PolicyDefinition, Subject}; ++ use crate::trust_store::Store; ++ use crate::types::DNSName; ++ use crate::{Budget, ChainBuilder, NameChain, ValidationError, ValidationErrorKind}; + + #[test] + fn test_validationerror_display() { +@@ -528,4 +595,102 @@ mod tests { + ValidationError::<PublicKeyErrorOps>::new(ValidationErrorKind::FatalError("oops")); + assert_eq!(err.to_string(), "fatal error: oops"); + } ++ ++ /// A `CryptoOps` whose public key extraction and signature verification ++ /// always succeed, so that `valid_issuer` can be driven to completion ++ /// without real cryptographic material. ++ struct NullOps; ++ ++ impl CryptoOps for NullOps { ++ type Key = (); ++ type Err = (); ++ type CertificateExtra = (); ++ type PolicyExtra = (); ++ ++ fn public_key(&self, _cert: &Certificate<'_>) -> Result<Self::Key, Self::Err> { ++ Ok(()) ++ } ++ ++ fn verify_signed_by( ++ &self, ++ _cert: &Certificate<'_>, ++ _key: &Self::Key, ++ ) -> Result<(), Self::Err> { ++ Ok(()) ++ } ++ ++ fn clone_public_key(_key: &Self::Key) -> Self::Key {} ++ ++ fn clone_extra(_extra: &Self::CertificateExtra) -> Self::CertificateExtra {} ++ } ++ ++ #[test] ++ fn test_clone() { ++ assert_eq!(NullOps::clone_public_key(&()), ()); ++ assert_eq!(NullOps::clone_extra(&()), ()); ++ } ++ ++ // A self-issued ("looping") CA certificate that is its own issuer. ++ fn looping_ca_pem() -> pem::Pem { ++ pem::parse( ++ "-----BEGIN CERTIFICATE----- ++MIIBcjCCARmgAwIBAgIBATAKBggqhkjOPQQDAjAhMR8wHQYDVQQDDBZsb29waW5n ++IHNlbGYtc2lnbmVkIENBMB4XDTIzMTIzMTAwMDAwMFoXDTI0MDEzMTAwMDAwMFow ++ITEfMB0GA1UEAwwWbG9vcGluZyBzZWxmLXNpZ25lZCBDQTBZMBMGByqGSM49AgEG ++CCqGSM49AwEHA0IABKAoXUGnHdfXJbSXjRjeW+PCVHmlo4KEki69N5pJUA0QyQMR ++v9ySOMnWf3Ea7TR4g3zdguwTP7LdpSku3uR1QkmjQjBAMA8GA1UdEwEB/wQFMAMB ++Af8wDgYDVR0PAQH/BAQDAgGGMB0GA1UdDgQWBBR23MGdG1Ma9iR+3CxKTafD/OE0 ++dTAKBggqhkjOPQQDAgNHADBEAiA4RCr07KfZdM16VfGNZAQFjvC60SWIU3RRVY/L ++qolIOwIgCaIgj9ipK0Q0p+45UJiq+L/ncrxsweJkFq/UYubzhX0= ++-----END CERTIFICATE-----", ++ ) ++ .unwrap() ++ } ++ ++ /// Exercises our pathlen overflow error scenario. ++ /// ++ /// This condition is logically unreachable from Python, since ++ /// we unconditionally limit signature checks to a number smaller ++ /// than `u8::MAX`, meaning that we always exhaust the signature budget ++ /// before potentially exhausting the pathlen budget. ++ /// ++ /// To test that directly, we manually lift the signature budget ++ /// and start our pathlen state right at `u8::MAX`, guaranteeing ++ /// an overflow on the immediate chain building step. ++ #[test] ++ fn test_build_chain_inner_depth_overflow() { ++ let pem = looping_ca_pem(); ++ let ca = asn1::parse_single::<Certificate<'_>>(pem.contents()).unwrap(); ++ let ca_exts = ca.extensions().ok().unwrap(); ++ ++ // The same self-issued CA is both the working certificate and its own ++ // (only) candidate issuer, so the search recurses on itself. ++ let working = VerificationCertificate::<NullOps>::new(&ca, ()); ++ let intermediates = [VerificationCertificate::<NullOps>::new(&ca, ())]; ++ let store: Store<'_, NullOps> = Store::new([]); ++ ++ let subject = Subject::DNS(DNSName::new("example.com").unwrap()); ++ let time = asn1::DateTime::new(2024, 1, 1, 0, 0, 0).unwrap(); ++ let policy_def = ++ PolicyDefinition::server(NullOps, subject, time, Some(u8::MAX), None, None).unwrap(); ++ let policy = Policy::new(&policy_def, ()); ++ ++ let builder = ChainBuilder::new(&intermediates, &policy, &store); ++ let mut budget = Budget { ++ name_constraint_checks: usize::MAX, ++ signature_checks: usize::MAX, ++ }; ++ ++ let name_chain = NameChain::new::<NullOps>(None, &ca_exts, false) ++ .ok() ++ .unwrap(); ++ let err = builder ++ .build_chain_inner(&working, u8::MAX, &ca_exts, name_chain, &mut budget) ++ .unwrap_err(); ++ ++ assert!(matches!( ++ err.kind, ++ ValidationErrorKind::Other(msg) if msg.contains("current depth calculation overflowed") ++ )); ++ } + } +diff --git a/src/rust/cryptography-x509-verification/src/policy/mod.rs b/src/rust/cryptography-x509-verification/src/policy/mod.rs +index 1d82e4b..b3a1f08 100644 +--- a/src/rust/cryptography-x509-verification/src/policy/mod.rs ++++ b/src/rust/cryptography-x509-verification/src/policy/mod.rs +@@ -30,7 +30,9 @@ pub use crate::policy::extension::{ + PresentExtensionValidatorCallback, + }; + use crate::types::{DNSName, DNSPattern, IPAddress}; +-use crate::{ValidationError, ValidationErrorKind, ValidationResult, VerificationCertificate}; ++use crate::{ ++ Budget, ValidationError, ValidationErrorKind, ValidationResult, VerificationCertificate, ++}; + + // RSA key constraints, as defined in CA/B 6.1.5. + const WEBPKI_MINIMUM_RSA_MODULUS: usize = 2048; +@@ -503,6 +505,7 @@ impl<'a, B: CryptoOps> Policy<'a, B> { + child: &VerificationCertificate<'chain, B>, + current_depth: u8, + issuer_extensions: &Extensions<'_>, ++ budget: &mut Budget, + ) -> ValidationResult<'chain, (), B> { + // The issuer needs to be a valid CA at the current depth. + self.permits_ca(issuer, current_depth, issuer_extensions) +@@ -563,6 +566,10 @@ impl<'a, B: CryptoOps> Policy<'a, B> { + } + } + ++ // Charge the (potentially expensive) signature verification against the ++ // budget before performing it, bounding the total work an attacker can ++ // force during chain building. ++ budget.signature_check()?; + if self.ops.verify_signed_by(child.certificate(), pk).is_err() { + return Err(ValidationError::new(ValidationErrorKind::Other( + "signature does not match".to_string(), +-- +2.43.0 + -- 2.43.0 ^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-09-11 14:18 UTC | newest] Thread overview: 2+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2026-09-11 14:18 [OE-core][wrynose][patch 1/2] python3-cryptography: Fix CVE-2026-69248 Vijay Anusuri 2026-09-11 14:18 ` [OE-core][wrynose][patch 2/2] python3-cryptography: Fix CVE-2026-69249 Vijay Anusuri
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