In order to parse the mask, xtopt_parse_hostmask() calls
xtopt_parse_plenmask() thereby limiting netmask support to prefix
lengths (alternatively specified in IP address notation).
In order to lift this impractical restriction, make
xtopt_parse_plenmask() aware of the fact that xtopt_parse_plen() may
fall back to xtopt_parse_mask() which correctly initializes val.hmask
itself and indicates non-CIDR-compatible masks by setting val.hlen to
-1.
So in order to support these odd masks, it is sufficient for
xtopt_parse_plenmask() to skip its mask building from val.hlen value and
take whatever val.hmask contains.
Fixes: 66266abd17adc ("libxtables: XTTYPE_HOSTMASK support")
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
libxtables/xtoptions.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/libxtables/xtoptions.c b/libxtables/xtoptions.c
index 433a686c2b595..02025e99d4832 100644
--- a/libxtables/xtoptions.c
+++ b/libxtables/xtoptions.c
@@ -692,6 +692,10 @@ static void xtopt_parse_plenmask(struct xt_option_call *cb)
xtopt_parse_plen(cb);
+ /* may not be convertible to CIDR notation */
+ if (cb->val.hlen == (uint8_t)-1)
+ goto out_put;
+
memset(mask, 0xFF, sizeof(union nf_inet_addr));
/* This shifting is AF-independent. */
if (cb->val.hlen == 0) {
@@ -712,6 +716,7 @@ static void xtopt_parse_plenmask(struct xt_option_call *cb)
mask[1] = htonl(mask[1]);
mask[2] = htonl(mask[2]);
mask[3] = htonl(mask[3]);
+out_put:
if (entry->flags & XTOPT_PUT)
memcpy(XTOPT_MKPTR(cb), mask, sizeof(union nf_inet_addr));
}
--
2.41.0
