diff options
Diffstat (limited to 'openssl/crypto/asn1/a_bitstr.c')
| -rw-r--r-- | openssl/crypto/asn1/a_bitstr.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/openssl/crypto/asn1/a_bitstr.c b/openssl/crypto/asn1/a_bitstr.c index 0fb9ce0c2..34179960b 100644 --- a/openssl/crypto/asn1/a_bitstr.c +++ b/openssl/crypto/asn1/a_bitstr.c @@ -223,3 +223,26 @@ int ASN1_BIT_STRING_get_bit(ASN1_BIT_STRING *a, int n) return((a->data[w]&v) != 0); } +/* + * Checks if the given bit string contains only bits specified by + * the flags vector. Returns 0 if there is at least one bit set in 'a' + * which is not specified in 'flags', 1 otherwise. + * 'len' is the length of 'flags'. + */ +int ASN1_BIT_STRING_check(ASN1_BIT_STRING *a, + unsigned char *flags, int flags_len) + { + int i, ok; + /* Check if there is one bit set at all. */ + if (!a || !a->data) return 1; + + /* Check each byte of the internal representation of the bit string. */ + ok = 1; + for (i = 0; i < a->length && ok; ++i) + { + unsigned char mask = i < flags_len ? ~flags[i] : 0xff; + /* We are done if there is an unneeded bit set. */ + ok = (a->data[i] & mask) == 0; + } + return ok; + } |