Automatically generated by Pod::Man 2.28 (Pod::Simple 3.30)

Standard preamble:
========================================================================
..

..

.. Set up some character translations and predefined strings. \*(-- will
give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
double quote, and \*(R" will give a right double quote. \*(C+ will
give a nicer C++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.

If the F register is turned on, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.

Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{ . nr % 0 . nr F 2 . \} . \} .\} .rr rF
Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
. \" fudge factors for nroff and troff . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] .\} . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents . \" corrections for vroff . \" for low resolution devices (crt and lpr) \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} ========================================================================

Title "CMS_verify 3" For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
.Vb 1 CMS_verify - verify a CMS SignedData structure .Ve Header "SYNOPSIS" .Vb 1 #include <openssl/cms.h> \& int CMS_verify(CMS_ContentInfo *cms, STACK_OF(X509) *certs, X509_STORE *store, BIO *indata, BIO *out, unsigned int flags); \& STACK_OF(X509) *CMS_get0_signers(CMS_ContentInfo *cms); .Ve Header "DESCRIPTION" \fICMS_verify() verifies a \s-1CMS\s0 SignedData structure. cms is the CMS_ContentInfo structure to verify. certs is a set of certificates in which to search for the signing certificate(s). store is a trusted certificate store used for chain verification. indata is the detached content if the content is not present in cms. The content is written to out if it is not \s-1NULL.\s0

\fBflags is an optional set of flags, which can be used to modify the verify operation.

\fICMS_get0_signers() retrieves the signing certificate(s) from cms, it must be called after a successful CMS_verify() operation.

Header "VERIFY PROCESS" Normally the verify process proceeds as follows.

Initially some sanity checks are performed on cms. The type of cms must be SignedData. There must be at least one signature on the data and if the content is detached indata cannot be \s-1NULL\s0.

An attempt is made to locate all the signing certificate(s), first looking in the certs parameter (if it is not \s-1NULL\s0) and then looking in any certificates contained in the cms structure itself. If any signing certificate cannot be located the operation fails.

Each signing certificate is chain verified using the smimesign purpose and the supplied trusted certificate store. Any internal certificates in the message are used as untrusted CAs. If \s-1CRL\s0 checking is enabled in store any internal CRLs are used in addition to attempting to look them up in store. If any chain verify fails an error code is returned.

Finally the signed content is read (and written to out is it is not \s-1NULL\s0) and the signature's checked.

If all signature's verify correctly then the function is successful.

Any of the following flags (ored together) can be passed in the flags parameter to change the default verify behaviour.

If \s-1CMS_NOINTERN\s0 is set the certificates in the message itself are not searched when locating the signing certificate(s). This means that all the signing certificates must be in the certs parameter.

If \s-1CMS_NOCRL\s0 is set and \s-1CRL\s0 checking is enabled in store then any CRLs in the message itself are ignored.

If the \s-1CMS_TEXT\s0 flag is set \s-1MIME\s0 headers for type text/plain are deleted from the content. If the content is not of type text/plain then an error is returned.

If \s-1CMS_NO_SIGNER_CERT_VERIFY\s0 is set the signing certificates are not verified.

If \s-1CMS_NO_ATTR_VERIFY\s0 is set the signed attributes signature is not verified.

If \s-1CMS_NO_CONTENT_VERIFY\s0 is set then the content digest is not checked.

Header "NOTES" One application of \s-1CMS_NOINTERN\s0 is to only accept messages signed by a small number of certificates. The acceptable certificates would be passed in the certs parameter. In this case if the signer is not one of the certificates supplied in certs then the verify will fail because the signer cannot be found.

In some cases the standard techniques for looking up and validating certificates are not appropriate: for example an application may wish to lookup certificates in a database or perform customised verification. This can be achieved by setting and verifying the signers certificates manually using the signed data utility functions.

Care should be taken when modifying the default verify behaviour, for example setting \s-1CMS_NO_CONTENT_VERIFY\s0 will totally disable all content verification and any modified content will be considered valid. This combination is however useful if one merely wishes to write the content to out and its validity is not considered important.

Chain verification should arguably be performed using the signing time rather than the current time. However since the signing time is supplied by the signer it cannot be trusted without additional evidence (such as a trusted timestamp).

Header "RETURN VALUES" \fICMS_verify() returns 1 for a successful verification and zero if an error occurred.

\fICMS_get0_signers() returns all signers or \s-1NULL\s0 if an error occurred.

The error can be obtained from ERR_get_error\|(3)

Header "BUGS" The trusted certificate store is not searched for the signing certificate, this is primarily due to the inadequacies of the current X509_STORE functionality.

The lack of single pass processing means that the signed content must all be held in memory if it is not detached.

Header "SEE ALSO" \fIERR_get_error\|(3), CMS_sign\|(3) Header "HISTORY" \fICMS_verify() was added to OpenSSL 0.9.8