From 6ceec21204e0260af2d50e9e987d0fe3c79c28d4 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 17 Oct 2023 15:50:21 +0200 Subject: [PATCH] evaluate: validate maximum log statement prefix length Otherwise too long string overruns the log prefix buffer. Fixes: e76bb3794018 ("src: allow for variables in the log prefix string") Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1714 Signed-off-by: Pablo Neira Ayuso --- src/evaluate.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/evaluate.c b/src/evaluate.c index b7ae9113..2196e928 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'; -- 2.47.3