neels has submitted this change. (
https://gerrit.osmocom.org/c/osmo-bsc/+/32421 )
Change subject: fix length check in abis_rsl_rx_rll()
......................................................................
fix length check in abis_rsl_rx_rll()
In abis_rsl_rx_rll(), we do the following header length check -- quick
challenge, can you spot the two bugs hidden here?
struct abis_rsl_rll_hdr *rllh;
if (msgb_l2len(msg) >
sizeof(struct abis_rsl_common_hdr) + sizeof(*rllh))
msg->l3h = &rllh->data[3];
Fix these bugs:
- struct abis_rsl_common_hdr is already included as the first member of
abis_rsl_rll_hdr, no need to add that.
- We are going to be accessing rrlh->data[3], so we must check for at
least sizeof(*rllh) + 4.
Change-Id: Ie4aee615c8c904ae8308ec0074d8bc5208137061
---
M src/osmo-bsc/abis_rsl.c
1 file changed, 26 insertions(+), 4 deletions(-)
Approvals:
laforge: Looks good to me, but someone else must approve
fixeria: Looks good to me, approved
pespin: Looks good to me, but someone else must approve
Jenkins Builder: Verified
diff --git a/src/osmo-bsc/abis_rsl.c b/src/osmo-bsc/abis_rsl.c
index 6370942..2fc640b 100644
--- a/src/osmo-bsc/abis_rsl.c
+++ b/src/osmo-bsc/abis_rsl.c
@@ -2500,8 +2500,7 @@
switch (rllh->c.msg_type) {
case RSL_MT_DATA_IND:
LOG_LCHAN(msg->lchan, LOGL_DEBUG, "SAPI=%u DATA INDICATION\n",
sapi);
- if (msgb_l2len(msg) >
- sizeof(struct abis_rsl_common_hdr) + sizeof(*rllh) &&
+ if (msgb_l2len(msg) > (sizeof(*rllh) + 3) &&
rllh->data[0] == RSL_IE_L3_INFO) {
msg->l3h = &rllh->data[3];
return gsm0408_rcvmsg(msg, rllh->link_id);
@@ -2543,8 +2542,7 @@
msg->lchan->sapis[sapi] = LCHAN_SAPI_MS;
osmo_fsm_inst_dispatch(msg->lchan->fi,
LCHAN_EV_RLL_ESTABLISH_IND, msg);
- if (msgb_l2len(msg) >
- sizeof(struct abis_rsl_common_hdr) + sizeof(*rllh) &&
+ if (msgb_l2len(msg) > (sizeof(*rllh) + 3) &&
rllh->data[0] == RSL_IE_L3_INFO) {
msg->l3h = &rllh->data[3];
return gsm0408_rcvmsg(msg, rllh->link_id);
--
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: Ie4aee615c8c904ae8308ec0074d8bc5208137061
Gerrit-Change-Number: 32421
Gerrit-PatchSet: 3
Gerrit-Owner: neels <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: neels <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>
Gerrit-CC: msuraev <[email protected]>
Gerrit-MessageType: merged
