mirror of git://git.gnupg.org/gnupg.git
scd:p15: Factor the commonKeyAttributes parser out.
* scd/app-p15.c (read_ef_prkdf): Fix detection of unsupported key objects. Factor some code out to ... (parse_common_key_attr): new. --
This commit is contained in:
Werner Koch
parent
b08418d22c
commit
5bcbc8cee3
340
scd/app-p15.c
340
scd/app-p15.c
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@ -1033,6 +1033,173 @@ parse_common_obj_attr (unsigned char const **buffer, size_t *size,
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}
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/* Parse the commonKeyAttributes. On success store the objid at
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* (R_OBJID/R_OBJIDLEN), sets the key usage flags at USAGEFLAGS and
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* the optiona key refrence at R_KEY_REFERENCE. The latter is only
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* valid if true is also stored at R_KEY_REFERENCE_VALID.
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*
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* Example data:
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*
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* 21 30 12: SEQUENCE { -- commonKeyAttributes
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* 23 04 1: OCTET STRING
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* : 01
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* 26 03 3: BIT STRING 6 unused bits
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* : '1000000000'B (bit 9)
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* 31 02 2: INTEGER 80 -- keyReference (optional)
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* : }
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*/
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static gpg_error_t
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parse_common_key_attr (unsigned char const **buffer, size_t *size,
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unsigned char **r_objid, size_t *r_objidlen,
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keyusage_flags_t *usageflags,
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unsigned long *r_key_reference,
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int *r_key_reference_valid)
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{
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gpg_error_t err;
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int where;
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int class, tag, constructed, ndef;
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size_t objlen, hdrlen, nnn;
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const unsigned char *ppp;
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int ignore_eof = 0;
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unsigned long ul;
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const unsigned char *objid = NULL;
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size_t objidlen;
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unsigned long key_reference = 0;
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int key_reference_valid = 0;
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*r_objid = NULL;
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*r_objidlen = 0;
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memset (usageflags, 0, sizeof *usageflags);
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*r_key_reference_valid = 0;
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where = __LINE__;
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err = parse_ber_header (buffer, size, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && (objlen > *size || tag != TAG_SEQUENCE))
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto leave;
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ppp = *buffer;
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nnn = objlen;
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*buffer += objlen;
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*size -= objlen;
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/* Get the Id. */
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where = __LINE__;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && (objlen > nnn
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|| class != CLASS_UNIVERSAL || tag != TAG_OCTET_STRING))
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto leave;
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objid = ppp;
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objidlen = objlen;
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ppp += objlen;
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nnn -= objlen;
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/* Get the KeyUsageFlags. */
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where = __LINE__;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && (objlen > nnn
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|| class != CLASS_UNIVERSAL || tag != TAG_BIT_STRING))
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto leave;
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err = parse_keyusage_flags (ppp, objlen, usageflags);
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if (err)
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goto leave;
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ppp += objlen;
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nnn -= objlen;
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ignore_eof = 1; /* Remaining items are optional. */
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/* Find the keyReference */
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where = __LINE__;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && objlen > nnn)
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto leave;
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if (class == CLASS_UNIVERSAL && tag == TAG_BOOLEAN)
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{
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/* Skip the native element. */
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ppp += objlen;
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nnn -= objlen;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && objlen > nnn)
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto leave;
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}
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if (class == CLASS_UNIVERSAL && tag == TAG_BIT_STRING)
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{
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/* Skip the accessFlags. */
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ppp += objlen;
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nnn -= objlen;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && objlen > nnn)
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto leave;
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}
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if (class == CLASS_UNIVERSAL && tag == TAG_INTEGER)
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{
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/* This is the keyReference. */
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for (ul=0; objlen; objlen--)
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{
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ul <<= 8;
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ul |= (*ppp++) & 0xff;
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nnn--;
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}
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key_reference = ul;
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key_reference_valid = 1;
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}
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leave:
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if (ignore_eof && gpg_err_code (err) == GPG_ERR_EOF)
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err = 0;
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if (!err)
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{
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if (!objid || !objidlen)
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err = gpg_error (GPG_ERR_INV_OBJ);
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else
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{
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*r_objid = xtrymalloc (objidlen);
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if (!*r_objid)
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err = gpg_error_from_syserror ();
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else
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{
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memcpy (*r_objid, objid, objidlen);
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*r_objidlen = objidlen;
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}
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}
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}
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if (!err && key_reference_valid)
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{
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*r_key_reference = key_reference;
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*r_key_reference_valid = 1;
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}
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if (err)
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log_error ("p15: error parsing commonKeyAttributes at %d: %s\n",
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where, gpg_strerror (err));
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return err;
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}
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/* Read and parse the Private Key Directory Files. */
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/*
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6034 (privatekeys)
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@ -1096,6 +1263,8 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
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int recno = 1;
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unsigned char *authid = NULL;
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size_t authidlen = 0;
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unsigned char *objid = NULL;
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size_t objidlen = 0;
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if (!fid)
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return gpg_error (GPG_ERR_NO_DATA); /* No private keys. */
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@ -1112,8 +1281,6 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
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p = buffer;
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n = buflen;
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/* FIXME: This shares a LOT of code with read_ef_cdf! */
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/* Loop over the records. We stop as soon as we detect a new record
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starting with 0x00 or 0xff as these values are commonly used to
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pad data blocks and are no valid ASN.1 encoding. Note the
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@ -1126,25 +1293,37 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
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const char *errstr = NULL;
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prkdf_object_t prkdf = NULL;
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unsigned long ul;
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const unsigned char *objid;
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size_t objidlen;
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keyusage_flags_t usageflags;
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unsigned long key_reference = 0;
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int key_reference_valid = 0;
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const char *s;
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where = __LINE__;
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err = parse_ber_header (&p, &n, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (err)
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;
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else if (objlen > n)
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err = gpg_error (GPG_ERR_INV_OBJ);
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else if (tag == TAG_SEQUENCE)
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;
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else if (class == CLASS_CONTEXT && tag == 0)
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; /* Seen with CardOS. */
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else if (class == CLASS_UNIVERSAL && tag == TAG_SEQUENCE)
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; /* PrivateRSAKeyAttributes */
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else if (class == CLASS_CONTEXT)
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{
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switch (tag)
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{
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case 0: errstr = "EC key objects are not supported"; break;
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case 1: errstr = "DH key objects are not supported"; break;
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case 2: errstr = "DSA key objects are not supported"; break;
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case 3: errstr = "KEA key objects are not supported"; break;
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default: errstr = "unknown privateKeyObject"; break;
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}
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goto parse_error;
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}
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else
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err = gpg_error (GPG_ERR_INV_OBJ);
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{
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err = gpg_error (GPG_ERR_INV_OBJ);
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goto parse_error;
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}
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if (err)
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{
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@ -1152,6 +1331,7 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
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gpg_strerror (err));
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goto leave;
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}
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pp = p;
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nn = objlen;
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p += objlen;
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@ -1166,105 +1346,14 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
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/* Parse the commonKeyAttributes. */
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where = __LINE__;
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err = parse_ber_header (&pp, &nn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && (objlen > nn || tag != TAG_SEQUENCE))
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err = gpg_error (GPG_ERR_INV_OBJ);
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xfree (objid);
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err = parse_common_key_attr (&pp, &nn,
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&objid, &objidlen,
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&usageflags,
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&key_reference, &key_reference_valid);
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if (err)
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goto parse_error;
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{
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const unsigned char *ppp = pp;
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size_t nnn = objlen;
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pp += objlen;
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nn -= objlen;
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/* Get the Id. */
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where = __LINE__;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && (objlen > nnn
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|| class != CLASS_UNIVERSAL || tag != TAG_OCTET_STRING))
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto parse_error;
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objid = ppp;
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objidlen = objlen;
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ppp += objlen;
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nnn -= objlen;
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/* Get the KeyUsageFlags. */
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where = __LINE__;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && (objlen > nnn
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|| class != CLASS_UNIVERSAL || tag != TAG_BIT_STRING))
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto parse_error;
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err = parse_keyusage_flags (ppp, objlen, &usageflags);
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if (err)
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goto parse_error;
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ppp += objlen;
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nnn -= objlen;
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/* Find the keyReference */
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where = __LINE__;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (gpg_err_code (err) == GPG_ERR_EOF)
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goto leave_cki;
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if (!err && objlen > nnn)
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto parse_error;
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if (class == CLASS_UNIVERSAL && tag == TAG_BOOLEAN)
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{
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/* Skip the native element. */
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ppp += objlen;
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nnn -= objlen;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (gpg_err_code (err) == GPG_ERR_EOF)
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goto leave_cki;
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if (!err && objlen > nnn)
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto parse_error;
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}
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if (class == CLASS_UNIVERSAL && tag == TAG_BIT_STRING)
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{
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/* Skip the accessFlags. */
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ppp += objlen;
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nnn -= objlen;
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err = parse_ber_header (&ppp, &nnn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (gpg_err_code (err) == GPG_ERR_EOF)
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goto leave_cki;
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if (!err && objlen > nnn)
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto parse_error;
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}
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if (class == CLASS_UNIVERSAL && tag == TAG_INTEGER)
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{
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/* Yep, this is the keyReference. */
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for (ul=0; objlen; objlen--)
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{
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ul <<= 8;
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ul |= (*ppp++) & 0xff;
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nnn--;
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}
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key_reference = ul;
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key_reference_valid = 1;
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}
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leave_cki:
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;
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}
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log_assert (objid);
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/* Skip subClassAttributes. */
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where = __LINE__;
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@ -1293,29 +1382,16 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
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where = __LINE__;
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err = parse_ber_header (&pp, &nn, &class, &tag, &constructed,
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&ndef, &objlen, &hdrlen);
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if (!err && objlen > nn)
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if (err)
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;
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else if (!err && objlen > nn)
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err = gpg_error (GPG_ERR_INV_OBJ);
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else if (class == CLASS_UNIVERSAL && tag == TAG_SEQUENCE)
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; /* A typeAttribute always starts with a sequence. */
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else
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err = gpg_error (GPG_ERR_INV_OBJ);
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if (err)
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goto parse_error;
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if (class == CLASS_UNIVERSAL && tag == TAG_SEQUENCE)
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; /* RSA */
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else if (class == CLASS_CONTEXT)
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{
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switch (tag)
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{
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case 0: errstr = "EC key objects are not supported"; break;
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case 1: errstr = "DH key objects are not supported"; break;
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case 2: errstr = "DSA key objects are not supported"; break;
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case 3: errstr = "KEA key objects are not supported"; break;
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default: errstr = "unknown privateKeyObject"; break;
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}
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goto parse_error;
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}
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else
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{
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err = gpg_error (GPG_ERR_INV_OBJ);
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goto parse_error;
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}
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nn = objlen;
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@ -1351,6 +1427,7 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
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errstr = "invalid path reference";
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goto parse_error;
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}
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/* Create a new PrKDF list item. */
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prkdf = xtrycalloc (1, (sizeof *prkdf
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- sizeof(unsigned short)
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@ -1361,14 +1438,8 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
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goto leave;
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}
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prkdf->objidlen = objidlen;
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prkdf->objid = xtrymalloc (objidlen);
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if (!prkdf->objid)
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{
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err = gpg_error_from_syserror ();
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xfree (prkdf);
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goto leave;
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}
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memcpy (prkdf->objid, objid, objidlen);
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prkdf->objid = objid;
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objid = NULL;
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if (authid)
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{
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prkdf->authidlen = authidlen;
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@ -1498,6 +1569,7 @@ read_ef_prkdf (app_t app, unsigned short fid, prkdf_object_t *result)
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leave:
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xfree (authid);
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xfree (objid);
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xfree (buffer);
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if (err)
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release_prkdflist (prkdflist);
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