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authorDavid Howells <dhowells@redhat.com>2015-08-05 12:54:46 +0100
committerDavid Howells <dhowells@redhat.com>2015-08-05 13:38:07 +0100
commit233ce79db4b23a174bcf30bde5d6ad913d5f46d3 (patch)
treefdf3021db1ab8f6d71908b6cc2a2e3afba94fb21
parent0d62e9dd6da45bbf0f33a8617afc5fe774c8f45f (diff)
ASN.1: Handle 'ANY OPTIONAL' in grammar
An ANY object in an ASN.1 grammar that is marked OPTIONAL should be skipped if there is no more data to be had. This can be tested by editing X.509 certificates or PKCS#7 messages to remove the NULL from subobjects that look like the following: SEQUENCE { OBJECT(2a864886f70d01010b); NULL(); } This is an algorithm identifier plus an optional parameter. The modified DER can be passed to one of: keyctl padd asymmetric "" @s </tmp/modified.x509 keyctl padd pkcs7_test foo @s </tmp/modified.pkcs7 It should work okay with the patch and produce EBADMSG without. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: David Woodhouse <David.Woodhouse@intel.com>
-rw-r--r--include/linux/asn1_ber_bytecode.h17
-rw-r--r--lib/asn1_decoder.c8
-rw-r--r--scripts/asn1_compiler.c3
3 files changed, 21 insertions, 7 deletions
diff --git a/include/linux/asn1_ber_bytecode.h b/include/linux/asn1_ber_bytecode.h
index 27f35780aecf..ab3a6c002f7b 100644
--- a/include/linux/asn1_ber_bytecode.h
+++ b/include/linux/asn1_ber_bytecode.h
@@ -45,24 +45,27 @@ enum asn1_opcode {
ASN1_OP_MATCH_JUMP = 0x04,
ASN1_OP_MATCH_JUMP_OR_SKIP = 0x05,
ASN1_OP_MATCH_ANY = 0x08,
+ ASN1_OP_MATCH_ANY_OR_SKIP = 0x09,
ASN1_OP_MATCH_ANY_ACT = 0x0a,
+ ASN1_OP_MATCH_ANY_ACT_OR_SKIP = 0x0b,
/* Everything before here matches unconditionally */
ASN1_OP_COND_MATCH_OR_SKIP = 0x11,
ASN1_OP_COND_MATCH_ACT_OR_SKIP = 0x13,
ASN1_OP_COND_MATCH_JUMP_OR_SKIP = 0x15,
ASN1_OP_COND_MATCH_ANY = 0x18,
+ ASN1_OP_COND_MATCH_ANY_OR_SKIP = 0x19,
ASN1_OP_COND_MATCH_ANY_ACT = 0x1a,
+ ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP = 0x1b,
/* Everything before here will want a tag from the data */
-#define ASN1_OP__MATCHES_TAG ASN1_OP_COND_MATCH_ANY_ACT
+#define ASN1_OP__MATCHES_TAG ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP
/* These are here to help fill up space */
- ASN1_OP_COND_FAIL = 0x1b,
- ASN1_OP_COMPLETE = 0x1c,
- ASN1_OP_ACT = 0x1d,
- ASN1_OP_MAYBE_ACT = 0x1e,
- ASN1_OP_RETURN = 0x1f,
+ ASN1_OP_COND_FAIL = 0x1c,
+ ASN1_OP_COMPLETE = 0x1d,
+ ASN1_OP_ACT = 0x1e,
+ ASN1_OP_MAYBE_ACT = 0x1f,
/* The following eight have bit 0 -> SET, 1 -> OF, 2 -> ACT */
ASN1_OP_END_SEQ = 0x20,
@@ -77,6 +80,8 @@ enum asn1_opcode {
#define ASN1_OP_END__OF 0x02
#define ASN1_OP_END__ACT 0x04
+ ASN1_OP_RETURN = 0x28,
+
ASN1_OP__NR
};
diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c
index 3f74dd3e2910..2b3f46c049d4 100644
--- a/lib/asn1_decoder.c
+++ b/lib/asn1_decoder.c
@@ -24,12 +24,16 @@ static const unsigned char asn1_op_lengths[ASN1_OP__NR] = {
[ASN1_OP_MATCH_JUMP] = 1 + 1 + 1,
[ASN1_OP_MATCH_JUMP_OR_SKIP] = 1 + 1 + 1,
[ASN1_OP_MATCH_ANY] = 1,
+ [ASN1_OP_MATCH_ANY_OR_SKIP] = 1,
[ASN1_OP_MATCH_ANY_ACT] = 1 + 1,
+ [ASN1_OP_MATCH_ANY_ACT_OR_SKIP] = 1 + 1,
[ASN1_OP_COND_MATCH_OR_SKIP] = 1 + 1,
[ASN1_OP_COND_MATCH_ACT_OR_SKIP] = 1 + 1 + 1,
[ASN1_OP_COND_MATCH_JUMP_OR_SKIP] = 1 + 1 + 1,
[ASN1_OP_COND_MATCH_ANY] = 1,
+ [ASN1_OP_COND_MATCH_ANY_OR_SKIP] = 1,
[ASN1_OP_COND_MATCH_ANY_ACT] = 1 + 1,
+ [ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP] = 1 + 1,
[ASN1_OP_COND_FAIL] = 1,
[ASN1_OP_COMPLETE] = 1,
[ASN1_OP_ACT] = 1 + 1,
@@ -304,7 +308,9 @@ next_op:
/* Decide how to handle the operation */
switch (op) {
case ASN1_OP_MATCH_ANY_ACT:
+ case ASN1_OP_MATCH_ANY_ACT_OR_SKIP:
case ASN1_OP_COND_MATCH_ANY_ACT:
+ case ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP:
ret = actions[machine[pc + 1]](context, hdr, tag, data + dp, len);
if (ret < 0)
return ret;
@@ -321,8 +327,10 @@ next_op:
case ASN1_OP_MATCH:
case ASN1_OP_MATCH_OR_SKIP:
case ASN1_OP_MATCH_ANY:
+ case ASN1_OP_MATCH_ANY_OR_SKIP:
case ASN1_OP_COND_MATCH_OR_SKIP:
case ASN1_OP_COND_MATCH_ANY:
+ case ASN1_OP_COND_MATCH_ANY_OR_SKIP:
skip_data:
if (!(flags & FLAG_CONS)) {
if (flags & FLAG_INDEFINITE_LENGTH) {
diff --git a/scripts/asn1_compiler.c b/scripts/asn1_compiler.c
index 0515bced929a..1c75e22b6385 100644
--- a/scripts/asn1_compiler.c
+++ b/scripts/asn1_compiler.c
@@ -1401,7 +1401,8 @@ static void render_element(FILE *out, struct element *e, struct element *tag)
act = e->action ? "_ACT" : "";
switch (e->compound) {
case ANY:
- render_opcode(out, "ASN1_OP_%sMATCH_ANY%s,", cond, act);
+ render_opcode(out, "ASN1_OP_%sMATCH_ANY%s%s,",
+ cond, act, skippable ? "_OR_SKIP" : "");
if (e->name)
render_more(out, "\t\t// %*.*s",
(int)e->name->size, (int)e->name->size,