[PATCH] libosmo-netif[master]: osmux: osmux_xfrm_output_pull: Improve checks and log of mal...

[Pau Espin Pedrol]

Review at  https://gerrit.osmocom.org/7783

osmux: osmux_xfrm_output_pull: Improve checks and log of malformed packets

Change-Id: I143805bb5ee9f5e3ada46114e380a03ede80df9f
Related: SYS#4182
---
M src/osmux.c
1 file changed, 11 insertions(+), 5 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/libosmo-netif refs/changes/83/7783/1

diff --git a/src/osmux.c b/src/osmux.c
index a0563d2..03db469 100644
--- a/src/osmux.c
+++ b/src/osmux.c
@@ -85,8 +85,13 @@
 		case OSMUX_FT_VOICE_AMR:
 			break;
 		case OSMUX_FT_DUMMY:
-			msgb_pull(msg, osmux_ft_dummy_size(osmuxh->amr_ft,
-							   osmuxh->ctr + 1));
+			len = osmux_ft_dummy_size(osmuxh->amr_ft, osmuxh->ctr + 1);
+			if (msgb_length(msg) < len) {
+				LOGP(DLMUX, LOGL_ERROR, "Discarding bad Dummy FT: %s\n",
+					osmo_hexdump(msg->data, msgb_length(msg)));
+				return NULL;
+			}
+			msgb_pull(msg, len);
 			goto next;
 		default:
 			LOGP(DLMUX, LOGL_ERROR, "Discarding unsupported Osmux FT %d\n",
@@ -102,9 +107,10 @@
 		len = osmo_amr_bytes(osmuxh->amr_ft) * (osmuxh->ctr+1) +
 			sizeof(struct osmux_hdr);
 
-		if (len > msg->len) {
-			LOGP(DLMUX, LOGL_ERROR, "Discarding malformed "
-						"OSMUX message\n");
+		if (msgb_length(msg) < len) {
+			LOGP(DLMUX, LOGL_ERROR,
+				"Discarding malformed OSMUX message: %s\n",
+				osmo_hexdump(msg->data, msgb_length(msg)));
 			return NULL;
 		}
 

-- 
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I143805bb5ee9f5e3ada46114e380a03ede80df9f
Gerrit-PatchSet: 1
Gerrit-Project: libosmo-netif
Gerrit-Branch: master
Gerrit-Owner: Pau Espin Pedrol <pespin at sysmocom.de>