Date: Wed, 14 Jul 2021 11:51:17 GMT From: Lutz Donnerhacke <donner@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 791035c8da5e - stable/13 - libalias: fix divide by zero causing panic Message-ID: <202107141151.16EBpHeY052192@gitrepo.freebsd.org>
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The branch stable/13 has been updated by donner: URL: https://cgit.FreeBSD.org/src/commit/?id=791035c8da5e8a693b3b954db67ff50b4f8695cb commit 791035c8da5e8a693b3b954db67ff50b4f8695cb Author: Stefan Eßer <se@FreeBSD.org> AuthorDate: 2021-07-10 11:00:56 +0000 Commit: Lutz Donnerhacke <donner@FreeBSD.org> CommitDate: 2021-07-14 11:49:21 +0000 libalias: fix divide by zero causing panic The packet_limit can fall to 0, leading to a divide by zero abort in the "packets % packet_limit". An possible solution would be to apply a lower limit of 1 after the calculation of packet_limit, but since any number modulo 1 gives 0, the more efficient solution is to skip the modulo operation for packet_limit <= 1. Reported by: Karl Denninger <karl@denninger.net> (cherry picked from commit 58080fbca09fda6d5f011d37059edbca8ceb4c58) --- sys/netinet/libalias/alias_db.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/netinet/libalias/alias_db.c b/sys/netinet/libalias/alias_db.c index 783a8ca3baa8..ed222c4133d4 100644 --- a/sys/netinet/libalias/alias_db.c +++ b/sys/netinet/libalias/alias_db.c @@ -1769,7 +1769,7 @@ HouseKeeping(struct libalias *la) * Reduce the amount of house keeping work substantially by * sampling over the packets. */ - if (packets % packet_limit == 0) { + if (packet_limit <= 1 || packets % packet_limit == 0) { time_t now; #ifdef _KERNEL
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