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authorDavid Howells <dhowells@redhat.com>2012-10-04 14:21:23 +0100
committerRusty Russell <rusty@rustcorp.com.au>2012-10-10 20:06:39 +1030
commitdbadc17683e6c673a69b236c0f041b931cc55c42 (patch)
treeec29aabfa428ca2c06caba94595b8c5d51a687e7 /lib
parent2f1c4fef103ef914e266588af263fb42b502b347 (diff)
downloadvexpress-lsk-dbadc17683e6c673a69b236c0f041b931cc55c42.tar.gz
X.509: Fix indefinite length element skip error handling
asn1_find_indefinite_length() returns an error indicator of -1, which the caller asn1_ber_decoder() places in a size_t (which is usually unsigned) and then checks to see whether it is less than 0 (which it can't be). This can lead to the following warning: lib/asn1_decoder.c:320 asn1_ber_decoder() warn: unsigned 'len' is never less than zero. Instead, asn1_find_indefinite_length() update the caller's idea of the data cursor and length separately from returning the error code. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'lib')
-rw-r--r--lib/asn1_decoder.c28
1 files changed, 19 insertions, 9 deletions
diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c
index 2e4196ddf06..de2c8b5a715 100644
--- a/lib/asn1_decoder.c
+++ b/lib/asn1_decoder.c
@@ -46,12 +46,18 @@ static const unsigned char asn1_op_lengths[ASN1_OP__NR] = {
/*
* Find the length of an indefinite length object
+ * @data: The data buffer
+ * @datalen: The end of the innermost containing element in the buffer
+ * @_dp: The data parse cursor (updated before returning)
+ * @_len: Where to return the size of the element.
+ * @_errmsg: Where to return a pointer to an error message on error
*/
static int asn1_find_indefinite_length(const unsigned char *data, size_t datalen,
- const char **_errmsg, size_t *_err_dp)
+ size_t *_dp, size_t *_len,
+ const char **_errmsg)
{
unsigned char tag, tmp;
- size_t dp = 0, len, n;
+ size_t dp = *_dp, len, n;
int indef_level = 1;
next_tag:
@@ -67,8 +73,11 @@ next_tag:
/* It appears to be an EOC. */
if (data[dp++] != 0)
goto invalid_eoc;
- if (--indef_level <= 0)
- return dp;
+ if (--indef_level <= 0) {
+ *_len = dp - *_dp;
+ *_dp = dp;
+ return 0;
+ }
goto next_tag;
}
@@ -122,7 +131,7 @@ data_overrun_error:
missing_eoc:
*_errmsg = "Missing EOC in indefinite len cons";
error:
- *_err_dp = dp;
+ *_dp = dp;
return -1;
}
@@ -315,13 +324,14 @@ next_op:
skip_data:
if (!(flags & FLAG_CONS)) {
if (flags & FLAG_INDEFINITE_LENGTH) {
- len = asn1_find_indefinite_length(
- data + dp, datalen - dp, &errmsg, &dp);
- if (len < 0)
+ ret = asn1_find_indefinite_length(
+ data, datalen, &dp, &len, &errmsg);
+ if (ret < 0)
goto error;
+ } else {
+ dp += len;
}
pr_debug("- LEAF: %zu\n", len);
- dp += len;
}
pc += asn1_op_lengths[op];
goto next_op;