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From 1ef47c304f226ca9f8a8d6bff1b43e617eafef19 Mon Sep 17 00:00:00 2001
From: Guy Harris <gharris@sonic.net>
Date: Mon, 21 Aug 2023 23:15:14 -0700
Subject: [PATCH] pgm: fix the way we step through the packet.
Step past the PGM header after we finish processing it and before we
process the message-type-specific header.
Step past the message-type-specific fixed-length header before we
process the stuff after that header.
This makes the code a bit clearer (by explicitly advancing bp by the
size of the stuff we just processed, rather than doing so by trickery
involving adding 1 to a pointer to a structure), and fixes the
processing of message types that don't have a message-type-specific
header (where we weren't stepping past the PGM header). It also affects
the way we handle messages of an unknown type.
(cherry picked from commit 9a3eebde95cf1032ac68ae4312e2db14bb1fe58d)
---
print-pgm.c | 29 +++++++++++++++--------------
tests/pgm_opts_asan.out | 2 +-
tests/pgm_opts_asan_2.out | 2 +-
tests/pgm_opts_asan_3.out | 2 +-
4 files changed, 18 insertions(+), 17 deletions(-)
diff --git a/print-pgm.c b/print-pgm.c
index 7672b616..f5ef7702 100644
--- a/print-pgm.c
+++ b/print-pgm.c
@@ -218,13 +218,14 @@ pgm_print(netdissect_options *ndo,
pgm->pgm_gsid[3],
pgm->pgm_gsid[4],
pgm->pgm_gsid[5]));
+ bp += sizeof(struct pgm_header);
switch (pgm->pgm_type) {
case PGM_SPM: {
const struct pgm_spm *spm;
- spm = (const struct pgm_spm *)(pgm + 1);
+ spm = (const struct pgm_spm *)bp;
ND_TCHECK(*spm);
- bp = (const u_char *) (spm + 1);
+ bp += sizeof(struct pgm_spm);
switch (EXTRACT_16BITS(&spm->pgms_nla_afi)) {
case AFNUM_INET:
@@ -253,21 +254,21 @@ pgm_print(netdissect_options *ndo,
case PGM_POLL: {
const struct pgm_poll *poll_msg;
- poll_msg = (const struct pgm_poll *)(pgm + 1);
+ poll_msg = (const struct pgm_poll *)bp;
ND_TCHECK(*poll_msg);
ND_PRINT((ndo, "POLL seq %u round %u",
EXTRACT_32BITS(&poll_msg->pgmp_seq),
EXTRACT_16BITS(&poll_msg->pgmp_round)));
- bp = (const u_char *) (poll_msg + 1);
+ bp += sizeof(struct pgm_poll);
break;
}
case PGM_POLR: {
const struct pgm_polr *polr;
uint32_t ivl, rnd, mask;
- polr = (const struct pgm_polr *)(pgm + 1);
+ polr = (const struct pgm_polr *)bp;
ND_TCHECK(*polr);
- bp = (const u_char *) (polr + 1);
+ bp += sizeof(struct pgm_polr);
switch (EXTRACT_16BITS(&polr->pgmp_nla_afi)) {
case AFNUM_INET:
@@ -305,24 +306,24 @@ pgm_print(netdissect_options *ndo,
case PGM_ODATA: {
const struct pgm_data *odata;
- odata = (const struct pgm_data *)(pgm + 1);
+ odata = (const struct pgm_data *)bp;
ND_TCHECK(*odata);
ND_PRINT((ndo, "ODATA trail %u seq %u",
EXTRACT_32BITS(&odata->pgmd_trailseq),
EXTRACT_32BITS(&odata->pgmd_seq)));
- bp = (const u_char *) (odata + 1);
+ bp += sizeof(struct pgm_data);
break;
}
case PGM_RDATA: {
const struct pgm_data *rdata;
- rdata = (const struct pgm_data *)(pgm + 1);
+ rdata = (const struct pgm_data *)bp;
ND_TCHECK(*rdata);
ND_PRINT((ndo, "RDATA trail %u seq %u",
EXTRACT_32BITS(&rdata->pgmd_trailseq),
EXTRACT_32BITS(&rdata->pgmd_seq)));
- bp = (const u_char *) (rdata + 1);
+ bp += sizeof(struct pgm_data);
break;
}
@@ -332,9 +333,9 @@ pgm_print(netdissect_options *ndo,
const struct pgm_nak *nak;
char source_buf[INET6_ADDRSTRLEN], group_buf[INET6_ADDRSTRLEN];
- nak = (const struct pgm_nak *)(pgm + 1);
+ nak = (const struct pgm_nak *)bp;
ND_TCHECK(*nak);
- bp = (const u_char *) (nak + 1);
+ bp += sizeof(struct pgm_nak);
/*
* Skip past the source, saving info along the way
@@ -402,11 +403,11 @@ pgm_print(netdissect_options *ndo,
case PGM_ACK: {
const struct pgm_ack *ack;
- ack = (const struct pgm_ack *)(pgm + 1);
+ ack = (const struct pgm_ack *)bp;
ND_TCHECK(*ack);
ND_PRINT((ndo, "ACK seq %u",
EXTRACT_32BITS(&ack->pgma_rx_max_seq)));
- bp = (const u_char *) (ack + 1);
+ bp += sizeof(struct pgm_ack);
break;
}
diff --git a/tests/pgm_opts_asan.out b/tests/pgm_opts_asan.out
index cc0607a4..b75868ac 100644
--- a/tests/pgm_opts_asan.out
+++ b/tests/pgm_opts_asan.out
@@ -1,2 +1,2 @@
IP (tos 0x41,ECT(1), id 0, offset 0, flags [none], proto PGM (113), length 32639, options (unknown 89 [bad length 232]), bad cksum 5959 (->9eb9)!)
- 128.121.89.107 > 89.89.16.63: 128.121.89.107.4 > 89.89.16.63.225: PGM, length 0 0x3414eb1f0022 UNKNOWN type 0x1f OPTS LEN 225 OPT_1F [13] OPT_06 [26] PATH_NLA [4] [|OPT]
+ 128.121.89.107 > 89.89.16.63: 128.121.89.107.4 > 89.89.16.63.225: PGM, length 0 0x3414eb1f0022 UNKNOWN type 0x1f[Bad OPT_LENGTH option, length 0 != 4]
diff --git a/tests/pgm_opts_asan_2.out b/tests/pgm_opts_asan_2.out
index 7e948d41..21cd69a7 100644
--- a/tests/pgm_opts_asan_2.out
+++ b/tests/pgm_opts_asan_2.out
@@ -1,2 +1,2 @@
IP (tos 0x41,ECT(1), id 0, offset 0, flags [none], proto PGM (113), length 32639, options (unknown 89 [bad length 232]), bad cksum 5959 (->96b9)!)
- 128.121.89.107 > 89.89.16.63: 128.121.89.107.4 > 89.89.16.63.225: PGM, length 0 0x3414eb1f0022 UNKNOWN type 0x1f OPTS LEN 225 OPT_1F [13] OPT_06 [26] [Bad OPT_PGMCC_DATA option, length 4 < 12]
+ 128.121.89.107 > 89.89.16.63: 128.121.89.107.4 > 89.89.16.63.225: PGM, length 0 0x3414eb1f0022 UNKNOWN type 0x1f[Bad OPT_LENGTH option, length 0 != 4]
diff --git a/tests/pgm_opts_asan_3.out b/tests/pgm_opts_asan_3.out
index 8a6bffd3..f3da1d38 100644
--- a/tests/pgm_opts_asan_3.out
+++ b/tests/pgm_opts_asan_3.out
@@ -1,2 +1,2 @@
IP (tos 0x41,ECT(1), id 0, offset 0, flags [none], proto PGM (113), length 32639, options (unknown 89 [bad length 232]), bad cksum 5959 (->f814)!)
- 128.121.89.16 > 0.89.16.63: 128.121.89.16.4 > 0.89.16.63.225: PGM, length 0 0x3414eb1f0022 UNKNOWN type 0x1f OPTS LEN 225 OPT_1F [13] OPT_06 [26] [Bad OPT_REDIRECT option, length 4 < 8]
+ 128.121.89.16 > 0.89.16.63: 128.121.89.16.4 > 0.89.16.63.225: PGM, length 0 0x3414eb1f0022 UNKNOWN type 0x1f[Bad OPT_LENGTH option, length 0 != 4]
--
2.41.0
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