[MERGED] openbsc[master]: Fix BTS features length check

[Max]

Max has submitted this change and it was merged.

Change subject: Fix BTS features length check
..


Fix BTS features length check

While fixing potentially incorrect memory access, the check for maximum
number of supported BTS features was incorrectly adjusted instead of
feature vectore length check next to it. Fix this by adjusting checks
properly and adding comments to avoid future confusion.

The error was introduced in a60bb3dd28ce9e3720f8ee1b262893f3e233e2e6.

Change-Id: I06d2498d730624d5da535f6add6fa98d004714ae
---
M openbsc/src/libbsc/abis_nm.c
1 file changed, 4 insertions(+), 4 deletions(-)

Approvals:
  Harald Welte: Looks good to me, approved
  Jenkins Builder: Verified



diff --git a/openbsc/src/libbsc/abis_nm.c b/openbsc/src/libbsc/abis_nm.c
index 1715688..019d039 100644
--- a/openbsc/src/libbsc/abis_nm.c
+++ b/openbsc/src/libbsc/abis_nm.c
@@ -484,13 +484,13 @@
if (TLVP_PRES_LEN(, NM_ATT_MANUF_ID, 2)) {
m_id_len = TLVP_LEN(, NM_ATT_MANUF_ID);
 
-   if (m_id_len > MAX_BTS_FEATURES/8 + 1) {
+   /* log potential BTS feature vector overflow */
+   if (m_id_len > sizeof(bts->_features_data))
LOGP(DNM, LOGL_NOTICE, "BTS%u Get Attributes Response: 
feature vector is truncated to %u bytes\n",
 bts->nr, MAX_BTS_FEATURES/8);
-   m_id_len = MAX_BTS_FEATURES/8;
-   }
 
-   if (m_id_len > sizeof(bts->_features_data))
+   /* check that max. expected BTS attribute is above given 
feature vector length */
+   if (m_id_len > OSMO_BYTES_FOR_BITS(_NUM_BTS_FEAT))
LOGP(DNM, LOGL_NOTICE, "BTS%u Get Attributes Response: 
reported unexpectedly long (%u bytes) "
 "feature vector - most likely it was compiled 
against newer BSC headers. "
 "Consider upgrading your BSC to later version.\n",

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Gerrit-MessageType: merged
Gerrit-Change-Id: I06d2498d730624d5da535f6add6fa98d004714ae
Gerrit-PatchSet: 3
Gerrit-Project: openbsc
Gerrit-Branch: master
Gerrit-Owner: Max 
Gerrit-Reviewer: Harald Welte 
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: Max 
Gerrit-Reviewer: Neels Hofmeyr 

openbsc[master]: Fix BTS features length check

[Harald Welte]

Patch Set 2: Code-Review+2

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Gerrit-MessageType: comment
Gerrit-Change-Id: I06d2498d730624d5da535f6add6fa98d004714ae
Gerrit-PatchSet: 2
Gerrit-Project: openbsc
Gerrit-Branch: master
Gerrit-Owner: Max 
Gerrit-Reviewer: Harald Welte 
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: Neels Hofmeyr 
Gerrit-HasComments: No

openbsc[master]: Fix BTS features length check

[Neels Hofmeyr]

Patch Set 1:

(1 comment)

https://gerrit.osmocom.org/#/c/2900/1/openbsc/src/libbsc/abis_nm.c
File openbsc/src/libbsc/abis_nm.c:

Line 493:   if (m_id_len > _NUM_BTS_FEAT/8 + 1)
> shouldn't this be
looking at enum gsm_bts_features that has _NUM_BTS_FEAT as last enum entry the 
/8 seems to be wrong entirely, and it seems that you need (m_id_len > 
_NUM_BTS_FEAT)?


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Gerrit-MessageType: comment
Gerrit-Change-Id: I06d2498d730624d5da535f6add6fa98d004714ae
Gerrit-PatchSet: 1
Gerrit-Project: openbsc
Gerrit-Branch: master
Gerrit-Owner: Max 
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: Neels Hofmeyr 
Gerrit-HasComments: Yes

openbsc[master]: Fix BTS features length check

[Neels Hofmeyr]

Patch Set 1: Code-Review-1

(1 comment)

https://gerrit.osmocom.org/#/c/2900/1/openbsc/src/libbsc/abis_nm.c
File openbsc/src/libbsc/abis_nm.c:

Line 493:   if (m_id_len > _NUM_BTS_FEAT/8 + 1)
shouldn't this be

  if (m_id_len > _NUM_BTS_FEAT/8)

? This patch allows m_id_len to be one larger than _NUM_BTS_FEAT/8.

Should the /8 also get a comment? "NUM" sounds like an actual amount; in 
contrast, division by 8 seems to be some buffer size with each feature taking 8 
bytes? Just asking because I'm not familiar...


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Gerrit-MessageType: comment
Gerrit-Change-Id: I06d2498d730624d5da535f6add6fa98d004714ae
Gerrit-PatchSet: 1
Gerrit-Project: openbsc
Gerrit-Branch: master
Gerrit-Owner: Max 
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: Neels Hofmeyr 
Gerrit-HasComments: Yes

[PATCH] openbsc[master]: Fix BTS features length check

[Max]

Review at  https://gerrit.osmocom.org/2900

Fix BTS features length check

While fixing potentially incorrect memory access, the check for maximum
number of supported BTS features was incorrectly adjusted instead of
feature vectore length check next to it. Fix this by adjusting checks
properly and adding comments to avoid future confusion.

The error was introduced in a60bb3dd28ce9e3720f8ee1b262893f3e233e2e6.

Change-Id: I06d2498d730624d5da535f6add6fa98d004714ae
---
M openbsc/src/libbsc/abis_nm.c
1 file changed, 4 insertions(+), 4 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/openbsc refs/changes/00/2900/1

diff --git a/openbsc/src/libbsc/abis_nm.c b/openbsc/src/libbsc/abis_nm.c
index 1715688..b0f3428 100644
--- a/openbsc/src/libbsc/abis_nm.c
+++ b/openbsc/src/libbsc/abis_nm.c
@@ -484,13 +484,13 @@
if (TLVP_PRES_LEN(, NM_ATT_MANUF_ID, 2)) {
m_id_len = TLVP_LEN(, NM_ATT_MANUF_ID);
 
-   if (m_id_len > MAX_BTS_FEATURES/8 + 1) {
+   /* log potential BTS feature vector overflow */
+   if (m_id_len > sizeof(bts->_features_data))
LOGP(DNM, LOGL_NOTICE, "BTS%u Get Attributes Response: 
feature vector is truncated to %u bytes\n",
 bts->nr, MAX_BTS_FEATURES/8);
-   m_id_len = MAX_BTS_FEATURES/8;
-   }
 
-   if (m_id_len > sizeof(bts->_features_data))
+   /* check that max. expected BTS attribute is above given 
feature vector length */
+   if (m_id_len > _NUM_BTS_FEAT/8 + 1)
LOGP(DNM, LOGL_NOTICE, "BTS%u Get Attributes Response: 
reported unexpectedly long (%u bytes) "
 "feature vector - most likely it was compiled 
against newer BSC headers. "
 "Consider upgrading your BSC to later version.\n",

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Gerrit-MessageType: newchange
Gerrit-Change-Id: I06d2498d730624d5da535f6add6fa98d004714ae
Gerrit-PatchSet: 1
Gerrit-Project: openbsc
Gerrit-Branch: master
Gerrit-Owner: Max