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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Subject: [PATCH nft] evaluate: validate maximum log statement prefix length
Date: Tue, 17 Oct 2023 15:52:46 +0200	[thread overview]
Message-ID: <20231017135246.16991-1-pablo@netfilter.org> (raw)

Otherwise too long string overruns the log prefix buffer.

Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1714
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/evaluate.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/evaluate.c b/src/evaluate.c
index b7ae9113b5a8..2196e92813d0 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -4175,8 +4175,13 @@ static int stmt_evaluate_log_prefix(struct eval_ctx *ctx, struct stmt *stmt)
 	size_t offset = 0;
 	struct expr *expr;
 
-	if (stmt->log.prefix->etype != EXPR_LIST)
+	if (stmt->log.prefix->etype != EXPR_LIST) {
+		if (stmt->log.prefix &&
+		    div_round_up(stmt->log.prefix->len, BITS_PER_BYTE) >= NF_LOG_PREFIXLEN)
+			return expr_error(ctx->msgs, stmt->log.prefix, "log prefix is too long");
+
 		return 0;
+	}
 
 	prefix[0] = '\0';
 
-- 
2.30.2


                 reply	other threads:[~2023-10-17 13:52 UTC|newest]

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