Date: Fri, 3 Dec 2021 09:05:02 -0500 From: mike tancsa <mike@sentex.net> To: Kristof Provost <kp@freebsd.org> Cc: freebsd-pf@freebsd.org Subject: Re: git: 7f944794868f - stable/12 - pf: Introduce ridentifier Message-ID: <1b5c4e46-7868-9fb9-4259-0c286b071310@sentex.net> In-Reply-To: <CAAcX-AHfWOcqEZBeFHGXo6VZ=ar6DyBEj1bvhjLHsX3UGCQVNw@mail.gmail.com> References: <202111261940.1AQJeGLZ022802@gitrepo.freebsd.org> <CAAcX-AFshuFUo7g9q_S3%2B5iS3Ko_Y%2BD0M5_nNEMPWOeMp66T3Q@mail.gmail.com> <52E4AB7A-6D27-4B11-ABCD-94BB12D389F4@FreeBSD.org> <CAAcX-AHfWOcqEZBeFHGXo6VZ=ar6DyBEj1bvhjLHsX3UGCQVNw@mail.gmail.com>
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Also, thanks for all the awesome PF work that you have done! Its much appreciated ---Mike On 12/3/2021 1:05 AM, Özkan KIRIK wrote: > Thank you Kristof. The patch works properly! > > On Wed, Dec 1, 2021 at 11:58 PM Kristof Provost <kp@freebsd.org> wrote: >> On 1 Dec 2021, at 5:59, Özkan KIRIK wrote: >> >> Because tshark/wireshark don't know this header change yet. >> >> I’ve looked at the Wireshark parser code, and .. well, it’s wrong. It arbitrarily adds 3 bytes to the header length, and that’s not the correct solution. I’m not going to implement kernel workarounds for application bugs. >> >> And even though tcpdump has been patched by this commit, it still >> cannot parse the packet properly also. >> >> Try this patch: >> >> diff --git a/sys/net/if_pflog.h b/sys/net/if_pflog.h >> index c77d8da1440a..93a69a2bb3a5 100644 >> --- a/sys/net/if_pflog.h >> +++ b/sys/net/if_pflog.h >> @@ -31,6 +31,8 @@ >> #ifndef _NET_IF_PFLOG_H_ >> #define _NET_IF_PFLOG_H_ >> >> +#include <net/bpf.h> >> + >> #define PFLOGIFS_MAX 16 >> >> #define PFLOG_RULESET_NAME_SIZE 16 >> @@ -51,11 +53,13 @@ struct pfloghdr { >> u_int8_t dir; >> u_int8_t pad[3]; >> u_int32_t ridentifier; >> + u_int8_t reserve; /* Appease broken software like Wireshark. */ >> + u_int8_t pad2[3]; >> }; >> >> -#define PFLOG_HDRLEN sizeof(struct pfloghdr) >> +#define PFLOG_HDRLEN BPF_WORDALIGN(offsetof(struct pfloghdr, pad2)) >> /* minus pad, also used as a signature */ >> -#define PFLOG_REAL_HDRLEN offsetof(struct pfloghdr, pad) >> +#define PFLOG_REAL_HDRLEN offsetof(struct pfloghdr, pad2) >> >> #ifdef _KERNEL >> struct pf_rule; >> diff --git a/sys/netpfil/pf/if_pflog.c b/sys/netpfil/pf/if_pflog.c >> index 4853c1301d6f..5ccdf3a7dd45 100644 >> --- a/sys/netpfil/pf/if_pflog.c >> +++ b/sys/netpfil/pf/if_pflog.c >> @@ -215,7 +215,8 @@ pflog_packet(struct pfi_kkif *kif, struct mbuf *m, sa_family_t af, u_int8_t dir, >> return (0); >> >> bzero(&hdr, sizeof(hdr)); >> - hdr.length = PFLOG_HDRLEN; >> + hdr.length = PFLOG_REAL_HDRLEN; >> hdr.af = af; >> hdr.action = rm->action; >> hdr.reason = reason; >> >> It looks like I had assumed that the header was expected to be aligned to 4 bytes, but it’s actually expected to be aligned to sizeof(long). This should fix that. >> >> I’ve gone one further and added a dummy field to arrange the updated struct so that Wireshark will work, essentially retaining its incorrect assumption. It really should be fixed as well though. >> >> Kristof >
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