Date: Tue, 28 May 2024 20:13:17 GMT From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 2780e5f43d5b - main - linux: allow RTM_GETADDR without full ifaddrmsg argument Message-ID: <202405282013.44SKDHtp031379@gitrepo.freebsd.org>
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The branch main has been updated by glebius: URL: https://cgit.FreeBSD.org/src/commit/?id=2780e5f43d5b0e8b155472300ee63816a660780e commit 2780e5f43d5b0e8b155472300ee63816a660780e Author: Gleb Smirnoff <glebius@FreeBSD.org> AuthorDate: 2024-05-28 20:13:08 +0000 Commit: Gleb Smirnoff <glebius@FreeBSD.org> CommitDate: 2024-05-28 20:13:08 +0000 linux: allow RTM_GETADDR without full ifaddrmsg argument Even modern glibc uses truncated argument for RTM_GETADDR when it wants to list all addresses in a system. See sysdeps/unix/sysv/linux/ifaddrs.c:__netlink_sendreq(). It sends a one char payload. Linux kernel allows that as long as given socket is not marked as a 'strict'. We have a similar flag in the general netlink code and it is checked in sys/netlink/netlink_message_parser.h:nl_parse_header(). If the flag is not present, parser will allocate a temporary zeroed buffer to make the message correct. The checks added in b977dd1ea5fb blocked such message before the parser. My reading of glibc says that there are two types of messages that are sent with __netlink_sendreq() - RTM_GETLINK and RTM_GETADDR. The RTM_GETLINK is binary compatible between Linux and FreeBSD and thus doesn't need any ABI handler. PR: 279012 Fixes: b977dd1ea5fbc2df3f1279330be4d089322eb2cf --- sys/compat/linux/linux_netlink.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sys/compat/linux/linux_netlink.c b/sys/compat/linux/linux_netlink.c index 8675f830b4ef..f51838ee00d7 100644 --- a/sys/compat/linux/linux_netlink.c +++ b/sys/compat/linux/linux_netlink.c @@ -94,7 +94,8 @@ rtnl_ifaddr_from_linux(struct nlmsghdr *hdr, struct nl_pstate *npt) struct ifaddrmsg *ifam = (struct ifaddrmsg *)(hdr + 1); sa_family_t f; - if (hdr->nlmsg_len < sizeof(struct nlmsghdr) + sizeof(struct ifaddrmsg)) + if (hdr->nlmsg_len < sizeof(struct nlmsghdr) + + offsetof(struct ifaddrmsg, ifa_family) + sizeof(ifam->ifa_family)) return (EBADMSG); if ((f = linux_to_bsd_domain(ifam->ifa_family)) == AF_UNKNOWN) return (EPFNOSUPPORT);
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