LIBRESSL-X509_STORE_CTX_GET_ERROR(3)

💅 X509_STORE_CTX_GET_ERROR(3) — get or set certificate verification status information

okay so first things first, bestie: this whole page lives in the Library Functions Manual and it's all about libcrypto, k? It's a big ol' grab bag of getters and setters that let you peek at (or poke at) the status info from a certificate verification run. Buckle up, there's a lot of functions but like... in a good way 🎀

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✨ NAME ✨

The full squad, in order, no cap:

• X509_STORE_CTX_get_error
• X509_STORE_CTX_set_error
• X509_STORE_CTX_get_error_depth
• X509_STORE_CTX_set_error_depth
• X509_STORE_CTX_get_current_cert
• X509_STORE_CTX_set_current_cert
• X509_STORE_CTX_get0_current_issuer
• X509_STORE_CTX_get0_current_crl
• X509_STORE_CTX_get0_parent_ctx
• X509_STORE_CTX_get_num_untrusted
• X509_STORE_CTX_get0_chain
• X509_STORE_CTX_get_chain
• X509_STORE_CTX_get1_chain
• X509_STORE_CTX_set0_verified_chain
• X509_verify_cert_error_string

...and together they get or set certificate verification status information. iconic 💅

#include <openssl/x509_vfy.h>

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🌸 SYNOPSIS 🌸

int
X509_STORE_CTX_get_error(X509_STORE_CTX *ctx);

void
X509_STORE_CTX_set_error(X509_STORE_CTX *ctx, int s);

int
X509_STORE_CTX_get_error_depth(X509_STORE_CTX *ctx);

void
X509_STORE_CTX_set_error_depth(X509_STORE_CTX *ctx, int depth);

X509 *
X509_STORE_CTX_get_current_cert(X509_STORE_CTX *ctx);

void
X509_STORE_CTX_set_current_cert(X509_STORE_CTX *ctx, X509 *cert);

X509 *
X509_STORE_CTX_get0_current_issuer(X509_STORE_CTX *ctx);

X509_CRL *
X509_STORE_CTX_get0_current_crl(X509_STORE_CTX *ctx);

X509_STORE_CTX *
X509_STORE_CTX_get0_parent_ctx(X509_STORE_CTX *ctx);

int
X509_STORE_CTX_get_num_untrusted(X509_STORE_CTX *ctx);

STACK_OF(X509) *
X509_STORE_CTX_get0_chain(X509_STORE_CTX *ctx);

STACK_OF(X509) *
X509_STORE_CTX_get_chain(X509_STORE_CTX *ctx);

STACK_OF(X509) *
X509_STORE_CTX_get1_chain(X509_STORE_CTX *ctx);

void
X509_STORE_CTX_set0_verified_chain(X509_STORE_CTX *ctx,
    STACK_OF(X509) *chain);

and then a whole separate include for this last one:

#include <openssl/x509.h>

const char *
X509_verify_cert_error_string(long n);

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🦋 DESCRIPTION 🦋

okay so like, most of these are the "what just happened" functions — you call them after X509_verify_cert(3) to inspect the status info from certificate verification. Some of them you can also call from inside a verification callback, to figure out the nature of an error while it's happening. very useful, very demure ✨

the error itself

• X509_STORE_CTX_get_error() — returns the error code of ctx. peek the ERROR CODES section for the full rundown of every single one, no skipping 🔥
• X509_STORE_CTX_set_error() — sets the error code of ctx to s. for example, a verification callback might use this to set an error based on some additional checks it did.

how deep does it go

• X509_STORE_CTX_get_error_depth() — returns the depth of the error. it's a non-negative integer representing where in the certificate chain the error occurred. 0? that's the end entity certificate. 1? that's the certificate which signed the end entity certificate. and so on, you get the vibe 👑
• X509_STORE_CTX_set_error_depth() — sets the error depth. use it in combination with X509_STORE_CTX_set_error() to set the depth at which an error condition was detected.

which cert tho

• X509_STORE_CTX_get_current_cert() — returns the certificate in ctx which caused the error, or NULL if no certificate is relevant.
• X509_STORE_CTX_set_current_cert() — sets the certificate which caused the error in ctx to the given cert. bestie, listen: this value is not intended to remain valid for very long, and it remains owned by the caller. it may be examined by a verification callback invoked to handle each error encountered during chain verification, and it's no longer required after such a callback. if a callback wants to save the certificate for use after it returns, it needs to increment its reference count via X509_up_ref(3). once such a saved certificate is no longer needed, it can be freed with X509_free(3). 🫶 (well, X509_free(3) — you know what I mean)

issuer + CRL drama

• X509_STORE_CTX_get0_current_issuer() — returns the certificate that caused issuer validation to fail, or NULL if no CA certificate is relevant.
• X509_STORE_CTX_get0_current_crl() — returns the certificate revocation list that caused CRL checking to fail, or NULL if no CRL is relevant.

the parent context plot twist 🌀

so when, during certification path validation, the need arises to check the validity of the certification path of a CRL issuer certificate, the library creates a new, temporary X509_STORE_CTX object. and if you call X509_STORE_CTX_get0_parent_ctx() on that temporary object, you get a pointer to the original certification path validation context. main character energy.

this may be useful in callback functions called from X509_verify_cert(3) or from its subroutines, to find out whether the callback is being called from the path validation of the target certificate or from the path validation of a related CRL issuer certificate — and if it's the latter, what the target certificate is. iykyk 💜

chain hangout

• X509_STORE_CTX_get0_chain() — returns an internal pointer to a complete validated chain of certificates if a previous call to X509_verify_cert(3) was successful. if that call was not successful, the returned chain may be incomplete or invalid. ⚠️
• X509_STORE_CTX_get_chain() — a deprecated alias of X509_STORE_CTX_get0_chain(), periodt.
• X509_STORE_CTX_get1_chain() — returns a deep copy of the same chain, which persists even after the ctx structure is freed. when it's no longer needed, it should be freed using sk_X509_pop_free(chain, X509_free).
• X509_STORE_CTX_set0_verified_chain() — frees the validated chain generated by a previous call to X509_verify_cert(3), if any, and replaces it with the given chain. ownership of the chain is transferred to the ctx, so it should not be freed by the caller. don't do it, bestie 🙈

the error string

• X509_verify_cert_error_string() — returns a human readable error string for verification error n. slay, readable output.

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🚨 real talk: the above functions should be used instead of directly referencing the fields in the X509_VERIFY_CTX structure. like, don't touch the internals, use the good functions, k?

😭 history lesson: in versions of OpenSSL before 1.0, the current certificate returned by X509_STORE_CTX_get_current_cert() was never NULL. so applications should check the return value before printing out any debugging information relating to the current certificate.

💀 and if an unrecognised error code is passed to X509_verify_cert_error_string(), the string "Unknown certificate verification error" is returned. this should never happen unless an invalid code is passed. literally should not be possible unless something's gone wrong.

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🌈 RETURN VALUES 🌈

• X509_STORE_CTX_get_error() returns X509_V_OK or an error code.
• X509_STORE_CTX_get_error_depth() returns a non-negative error depth.
• X509_STORE_CTX_get_current_cert(), X509_STORE_CTX_get0_current_issuer(), and X509_STORE_CTX_get0_current_crl() return the object which caused the error, or NULL if no object of the requested kind is relevant to the error.
• X509_STORE_CTX_get0_parent_ctx() returns the parent context, or NULL if ctx is not a temporary child context used for path validation of a CRL issuer certificate.
• X509_STORE_CTX_get_num_untrusted() returns the number of untrusted certificates that were used in building the chain during a call to X509_verify_cert(3).
• X509_STORE_CTX_get0_chain(), X509_STORE_CTX_get_chain(), and X509_STORE_CTX_get1_chain() return a pointer to a stack of certificates, or NULL if an error occurs.
• X509_verify_cert_error_string() returns a human readable error string for verification error n.

✨ ERROR CODES ✨

Okay bestie, here’s the full error-code lineup 💖. Some of these are defined but currently never returned — those are marked “unused” below. Do not come for me, I’m just the messenger 🫶.

• X509_V_OK — ok — the operation was successful. Slay. ✨
• X509_V_ERR_UNSPECIFIED — Unspecified certificate verification error — an error popped up during certificate verification and the internal routines failed to set a more specific error. Not them being vague 😭.
• X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT — unable to get issuer certificate — the issuer certificate of a locally looked up certificate could not be found. This normally means the list of trusted certificates is not complete. 🥲
• X509_V_ERR_UNABLE_TO_GET_CRL — unable to get certificate CRL — the CRL of a certificate could not be found.
• X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE — unable to decrypt certificate's signature — the certificate signature could not be decrypted. This means the actual signature value could not be determined rather than it not matching the expected value. This is only meaningful for RSA keys. 🔑
• X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE — unable to decrypt CRL's signature — the CRL signature could not be decrypted: this means the actual signature value could not be determined rather than it not matching the expected value. Unused. 💀
• X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY — unable to decode issuer public key — the public key in the certificate SubjectPublicKeyInfo could not be read.
• X509_V_ERR_CERT_SIGNATURE_FAILURE — certificate signature failure — the signature of the certificate is invalid. Not iconic. 🙈
• X509_V_ERR_CRL_SIGNATURE_FAILURE — CRL signature failure — the signature of the CRL is invalid.
• X509_V_ERR_CERT_NOT_YET_VALID — certificate is not yet valid — the certificate is not yet valid: the notBefore date is after the current time. Early bird behavior, honestly. ⏰
• X509_V_ERR_CERT_HAS_EXPIRED — certificate has expired — the certificate has expired: that is the notAfter date is before the current time. RIP boo 🪦.
• X509_V_ERR_CRL_NOT_YET_VALID — CRL is not yet valid — the CRL is not yet valid.
• X509_V_ERR_CRL_HAS_EXPIRED — CRL has expired — the CRL has expired.
• X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD — format error in certificate's notBefore field — the certificate notBefore field contains an invalid time.
• X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD — format error in certificate's notAfter field — the certificate notAfter field contains an invalid time.
• X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD — format error in CRL's lastUpdate field — the CRL thisUpdate field (sic!) contains an invalid time. Both the name of the error constant and the text of the error message give a wrong name for the field that contains the problem. Not the typo doing a little chaos 😭.
• X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD — format error in CRL's nextUpdate field — the CRL nextUpdate field contains an invalid time.
• X509_V_ERR_OUT_OF_MEM — out of memory — an error occurred trying to allocate memory. This should never happen. Bestie if this happens we’re in our flop era 💀.
• X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT — self signed certificate — the passed certificate is self signed and the same certificate cannot be found in the list of trusted certificates.
• X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN — self signed certificate in certificate chain — the certificate chain could be built up using the untrusted certificates but the root could not be found locally.
• X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY — unable to get local issuer certificate — the issuer certificate could not be found: this occurs if the issuer certificate of an untrusted certificate cannot be found.
• X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE — unable to verify the first certificate — no signatures could be verified because the chain contains only one certificate and it is not self signed. 🍃
• X509_V_ERR_CERT_CHAIN_TOO_LONG — certificate chain too long — the certificate chain length is greater than the supplied maximum depth. It’s giving “too much” 💅.
• X509_V_ERR_CERT_REVOKED — certificate revoked — the certificate has been revoked.
• X509_V_ERR_INVALID_CA — invalid CA certificate — a CA certificate is invalid. Either it is not a CA or its extensions are not consistent with the supplied purpose.
• X509_V_ERR_PATH_LENGTH_EXCEEDED — path length constraint exceeded — the basicConstraints path-length parameter has been exceeded.
• X509_V_ERR_INVALID_PURPOSE — unsupported certificate purpose — the supplied certificate cannot be used for the specified purpose.
• X509_V_ERR_CERT_UNTRUSTED — certificate not trusted — the root CA is not marked as trusted for the specified purpose.
• X509_V_ERR_CERT_REJECTED — certificate rejected — the root CA is marked to reject the specified purpose. Blocked and reported 🚫.
• X509_V_ERR_SUBJECT_ISSUER_MISMATCH — subject issuer mismatch — the current candidate issuer certificate was rejected because its subject name did not match the issuer name of the current certificate. This is only set if issuer check debugging is enabled; it is used for status notification and is not in itself an error.
• X509_V_ERR_AKID_SKID_MISMATCH — authority and subject key identifier mismatch — the current candidate issuer certificate was rejected because its subject key identifier was present and did not match the authority key identifier current certificate. This is only set if issuer check debugging is enabled; it is used for status notification and is not in itself an error.
• X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH — authority and issuer serial number mismatch — the current candidate issuer certificate was rejected because its issuer name and serial number was present and did not match the authority key identifier of the current certificate. This is only set if issuer check debugging is enabled; it is used for status notification and is not in itself an error.
• X509_V_ERR_KEYUSAGE_NO_CERTSIGN — key usage does not include certificate signing — the current candidate issuer certificate was rejected because its keyUsage extension does not permit certificate signing. This is only set if issuer check debugging is enabled it is used for status notification and is not in itself an error.
• X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER — unable to get CRL issuer certificate — the CRL’s issuer could not be found: there is no alternative CRL issuer set on ctx and the last certificate in the chain is not self signed.
• X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION — unhandled critical extension — the certificate contains a critical extension that is unsupported by the library. The library is like “I don’t know her” 😭.
• X509_V_ERR_KEYUSAGE_NO_CRL_SIGN — key usage does not include CRL signing — the CRL issuer has a keyUsage extension with unset cRLSign bit.
• X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION — unhandled critical CRL extension — the CRL contains a critical extension that is unsupported by the library.
• X509_V_ERR_INVALID_EXTENSION — invalid or inconsistent certificate extension — a certificate extension had an invalid value (for example an incorrect encoding) or some value inconsistent with other extensions.
• X509_V_ERR_INVALID_POLICY_EXTENSION — invalid or inconsistent certificate policy extension — a certificate policies extension had an invalid value (for example an incorrect encoding) or some value inconsistent with other extensions. This error only occurs if policy processing is enabled.
• X509_V_ERR_NO_EXPLICIT_POLICY — no explicit policy — the verification flags were set to require an explicit policy but none was present.
• X509_V_ERR_DIFFERENT_CRL_SCOPE — different CRL scope — the only CRLs that could be found did not match the scope of the certificate.
• X509_V_ERR_UNSUPPORTED_EXTENSION_FEATURE — unsupported extension feature — some feature of a certificate extension is not supported. Unused. 💀
• X509_V_ERR_UNNESTED_RESOURCE — RFC 3779 resource not subset of parent's resources — when walking up a certificate chain, all resources specified in RFC 3779 extensions must be contained in the resources delegated in the issuer’s RFC 3779 extensions. The error indicates that this is not the case or that the trust anchor has inheritance.
• X509_V_ERR_PERMITTED_VIOLATION — permitted subtree violation — a name constraint violation occurred in the permitted subtrees.
• X509_V_ERR_EXCLUDED_VIOLATION — excluded subtree violation — a name constraint violation occurred in the excluded subtrees.
• X509_V_ERR_SUBTREE_MINMAX — name constraints minimum and maximum not supported — a certificate name constraints extension included a minimum or maximum field: this is not supported.
• X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE — unsupported name constraint type — an unsupported name constraint type was encountered. OpenSSL currently only supports directory name, DNS name, email and URI types.
• X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX — unsupported or invalid name constraint syntax — the format of the name constraint is not recognised: for example an email address format of a form not mentioned in RFC 3280. This could be caused by a garbage extension or some new feature not currently supported.
• X509_V_ERR_CRL_PATH_VALIDATION_ERROR — CRL path validation error — an error occurred when attempting to verify the CRL path. This error can only happen if extended CRL checking is enabled.
• X509_V_ERR_APPLICATION_VERIFICATION — application verification failure — an application specific error. This will never be returned unless explicitly set by an application.

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🌈 SEE ALSO 🌈

Go peek at these besties when you’re done here 🫶:

• X509_STORE_CTX_new(3)
• X509_STORE_CTX_set_verify(3)
• X509_STORE_CTX_set_verify_cb(3)
• X509_STORE_set_verify_cb(3)
• X509_up_ref(3)
• X509_verify_cert(3)

📜 HISTORY 📜

okay so story time, bestie, because the lore here is actually iconic 💅

The OG squad — X509_STORE_CTX_get_error(), X509_STORE_CTX_set_error(), X509_STORE_CTX_get_error_depth(), X509_STORE_CTX_get_current_cert(), X509_STORE_CTX_get_chain(), and X509_verify_cert_error_string() — first appeared in SSLeay 0.8.0 and have been available since OpenBSD 2.4. like, they've been serving since before most of us could read 🫶

Then X509_STORE_CTX_get1_chain() pulled up, first appeared in OpenSSL 0.9.5, and has been available since OpenBSD 2.7. a whole era later, ngl ✨

X509_STORE_CTX_get0_current_issuer(), X509_STORE_CTX_get0_current_crl(), and X509_STORE_CTX_get0_parent_ctx() are the OpenSSL 1.0.0 baddies — first appeared there, and have been available since OpenBSD 4.9. glow-up fr 🌸

X509_STORE_CTX_get0_chain() came through in OpenSSL 1.1.0 and has been available since OpenBSD 6.3. we love a late arrival that still ate 💖

And the newest main characters: X509_STORE_CTX_set_error_depth(), X509_STORE_CTX_set_current_cert(), X509_STORE_CTX_get_num_untrusted(), and X509_STORE_CTX_set0_verified_chain() — first appeared in OpenSSL 1.1.0, and have been available since OpenBSD 7.1. fresh out the gate and already iconic 👑

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and that's the whole page, bestie!! 🎀 this little masterpiece lives in the Debian edition of the manual, dated August 29, 2026 — screenshot it, cite it, put it on your fridge, whatever, it's yours now 💜🦋