From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Subject: [PATCH nft] netlink_delinearize: use-after-free in expr_postprocess_string()
Date: Thu, 13 Jun 2019 11:49:45 +0200 [thread overview]
Message-ID: <20190613094945.2871-1-pablo@netfilter.org> (raw)
escaped_string_wildcard_expr_alloc() may reallocate the expression.
valgrind reports errors like this one:
==29945== Invalid write of size 4
==29945== at 0x72EE944: __expr_postprocess_string (netlink_delinearize.c:2006)
==29945== by 0x72EE944: expr_postprocess_string (netlink_delinearize.c:2016)
==29945== by 0x72EE944: expr_postprocess (netlink_delinearize.c:2120)
==29945== by 0x72EE5A7: expr_postprocess (netlink_delinearize.c:2094)
==29945== by 0x72EF23B: stmt_expr_postprocess (netlink_delinearize.c:2289)
==29945== by 0x72EF23B: rule_parse_postprocess (netlink_delinearize.c:2510)
==29945== by 0x72EF23B: netlink_delinearize_rule (netlink_delinearize.c:2650)
==29945== by 0x72E6F63: list_rule_cb (netlink.c:330)
==29945== by 0x7770BD3: nftnl_rule_list_foreach (rule.c:810)
==29945== by 0x72E739E: netlink_list_rules (netlink.c:349)
==29945== by 0x72E739E: netlink_list_table (netlink.c:490)
==29945== by 0x72D4A89: cache_init_objects (rule.c:194)
==29945== by 0x72D4A89: cache_init (rule.c:216)
==29945== by 0x72D4A89: cache_update (rule.c:266)
==29945== by 0x72F829E: nft_evaluate (libnftables.c:388)
==29945== by 0x72F8A5B: nft_run_cmd_from_buffer (libnftables.c:428)
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
src/netlink_delinearize.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index 6576687ce627..9f25007f6195 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -2003,7 +2003,7 @@ static bool __expr_postprocess_string(struct expr **exprp)
escaped_string_wildcard_expr_alloc(exprp, len);
mpz_clear(tmp);
- expr->len = len;
+ (*exprp)->len = len;
return nulterminated;
}
@@ -2119,6 +2119,7 @@ static void expr_postprocess(struct rule_pp_ctx *ctx, struct expr **exprp)
if (expr_basetype(expr)->type == TYPE_STRING)
*exprp = expr_postprocess_string(expr);
+ expr = *exprp;
if (expr->dtype->basetype != NULL &&
expr->dtype->basetype->type == TYPE_BITMASK)
*exprp = bitmask_expr_to_binops(expr);
--
2.11.0
reply other threads:[~2019-06-13 15:42 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190613094945.2871-1-pablo@netfilter.org \
--to=pablo@netfilter.org \
--cc=netfilter-devel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).