Make the ober_get_* set of function to accept a NULL-pointer.

This allows us to do ber-type checking inside ober_scanf_elements, which
will allow for stricter ASN.1 parsing in the future.

Manpage feedback and OK claudio@, jmc@
OK claudio@

diff --git a/lib/libutil/ber.c b/lib/libutil/ber.c
index 25b7830..175e2bb 100644 (file)
--- a/lib/libutil/ber.c
+++ b/lib/libutil/ber.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ber.c,v 1.20 2021/01/28 19:56:33 martijn Exp $ */
+/*     $OpenBSD: ber.c,v 1.21 2021/02/22 17:15:02 martijn Exp $ */
 
 /*
  * Copyright (c) 2007, 2012 Reyk Floeter <reyk@openbsd.org>
@@ -213,7 +213,8 @@ ober_get_integer(struct ber_element *elm, long long *n)
        if (elm->be_encoding != BER_TYPE_INTEGER)
                return -1;
 
-       *n = elm->be_numeric;
+       if (n != NULL)
+               *n = elm->be_numeric;
        return 0;
 }
 
@@ -223,7 +224,8 @@ ober_get_enumerated(struct ber_element *elm, long long *n)
        if (elm->be_encoding != BER_TYPE_ENUMERATED)
                return -1;
 
-       *n = elm->be_numeric;
+       if (n != NULL)
+               *n = elm->be_numeric;
        return 0;
 }
 
@@ -249,7 +251,8 @@ ober_get_boolean(struct ber_element *elm, int *b)
        if (elm->be_encoding != BER_TYPE_BOOLEAN)
                return -1;
 
-       *b = !(elm->be_numeric == 0);
+       if (b != NULL)
+               *b = !(elm->be_numeric == 0);
        return 0;
 }
 
@@ -299,7 +302,8 @@ ober_get_string(struct ber_element *elm, char **s)
                return -1;
 #endif
 
-       *s = elm->be_val;
+       if (s != NULL)
+               *s = elm->be_val;
        return 0;
 }
 
@@ -309,8 +313,14 @@ ober_get_nstring(struct ber_element *elm, void **p, size_t *len)
        if (elm->be_encoding != BER_TYPE_OCTETSTRING)
                return -1;
 
-       *p = elm->be_val;
-       *len = elm->be_len;
+       if (len != NULL)
+               *len = elm->be_len;
+       if (p != NULL) {
+               if (len != NULL)
+                       *p = elm->be_val;
+               else
+                       *p = NULL;
+       }
        return 0;
 }
 
@@ -320,8 +330,10 @@ ober_get_ostring(struct ber_element *elm, struct ber_octetstring *s)
        if (elm->be_encoding != BER_TYPE_OCTETSTRING)
                return -1;
 
-       s->ostr_val = elm->be_val;
-       s->ostr_len = elm->be_len;
+       if (s != NULL) {
+               s->ostr_val = elm->be_val;
+               s->ostr_len = elm->be_len;
+       }
        return 0;
 }
 
@@ -354,8 +366,14 @@ ober_get_bitstring(struct ber_element *elm, void **v, size_t *len)
        if (elm->be_encoding != BER_TYPE_BITSTRING)
                return -1;
 
-       *v = elm->be_val;
-       *len = elm->be_len;
+       if (len != NULL)
+               *len = elm->be_len;
+       if (v != NULL) {
+               if (len != NULL)
+                       *v = elm->be_val;
+               else
+                       *v = NULL;
+       }
        return 0;
 }
 
@@ -543,6 +561,9 @@ ober_get_oid(struct ber_element *elm, struct ber_oid *o)
        if (elm->be_encoding != BER_TYPE_OBJECT)
                return (-1);
 
+       if (o == NULL)
+               return 0;
+
        buf = elm->be_val;
        len = elm->be_len;
 
@@ -709,7 +730,8 @@ ober_scanf_elements(struct ber_element *ber, char *fmt, ...)
                        d = va_arg(ap, int *);
                        if (ober_get_integer(ber, &l) == -1)
                                goto fail;
-                       *d = l;
+                       if (d != NULL)
+                               *d = l;
                        ret++;
                        break;
                case 'e':
@@ -747,8 +769,10 @@ ober_scanf_elements(struct ber_element *ber, char *fmt, ...)
                case 't':
                        d = va_arg(ap, int *);
                        t = va_arg(ap, unsigned int *);
-                       *d = ber->be_class;
-                       *t = ber->be_type;
+                       if (d != NULL)
+                               *d = ber->be_class;
+                       if (t != NULL)
+                               *t = ber->be_type;
                        ret++;
                        continue;
                case 'x':

diff --git a/lib/libutil/ober_get_string.3 b/lib/libutil/ober_get_string.3
index fda9f35..72092d7 100644 (file)
--- a/lib/libutil/ober_get_string.3
+++ b/lib/libutil/ober_get_string.3
@@ -1,4 +1,4 @@
-.\" $OpenBSD: ober_get_string.3,v 1.3 2021/01/28 19:56:33 martijn Exp $
+.\" $OpenBSD: ober_get_string.3,v 1.4 2021/02/22 17:15:02 martijn Exp $
 .\"
 .\" Copyright (c) 2007, 2012 Reyk Floeter <reyk@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: January 28 2021 $
+.Dd $Mdocdate: February 22 2021 $
 .Dt OBER_GET_STRING 3
 .Os
 .Sh NAME
@@ -62,12 +62,27 @@
 Functions which take two arguments save the value contained in the
 .Fa root
 element into the storage location pointed to by the second argument.
+If the storage location is
+.Dv NULL
+then only a type check is performed.
 Additionally,
 .Fn ober_get_nstring
 and
 .Fn ober_get_bitstring
 save the number of bytes contained in the string into
 .Pf * Fa size .
+If 
+.Fa buf
+is
+.Dv NULL
+and size is not
+.Dv NULL ,
+size is set.
+.Fa size
+must not be
+.Dv NULL
+to return a valid
+.Fa buf .
 .Pp
 .Fn ober_scanf_elements
 retrieves the values from zero or more elements starting at