gsm/{bsslap,bssmap_le}: zero-initialize structs using memset()
In the unit tests we're using memcmp() to compare decoding results
against the expected results. This is a reasonable approach, but
there is a pitfall: not only the struct fields are compared, but
also the padding bytes preceding/following them.
When using gcc's extension zero-initializer {} or even the standard
approved { 0 } zero-initializer, padding bytes are not guaranteed
to be zeroed. Even worse, according to [1], the init behavior is
inconsistent between gcc and clang and optimization levels.
All decoding functions in {bsslap,bssmap_le}.c currently use gcc's
extension zero-initializer {}. This is not a problem when building
with CC=gcc, but with CC=clang the bssmap_le_test fails due to
mismatch of padding bytes in struct lcs_cause_ie:
[4] PERFORM LOCATION RESPONSE: ERROR: decoded PDU != encoded PDU
[5] PERFORM LOCATION RESPONSE: ERROR: decoded PDU != encoded PDU
[6] PERFORM LOCATION ABORT: ERROR: decoded PDU != encoded PDU
Out of the known struct initialization methods, only the memset()
has consistent behavior and sets all bytes to zero, including the
padding ones. Using it fixes the bssmap_le_test for CC=clang.
[1] https://interrupt.memfault.com/blog/c-struct-padding-initialization
Change-Id: Ib16964b16eb04315efc416164ed46c15b5dc7254
Fixes: OS#5923
diff --git a/src/gsm/bsslap.c b/src/gsm/bsslap.c
index 7b31d1f..70ded13 100644
--- a/src/gsm/bsslap.c
+++ b/src/gsm/bsslap.c
@@ -217,7 +217,7 @@
int ies_len;
struct tlv_parsed tp;
- *pdu = (struct bsslap_pdu){};
+ memset(pdu, 0x00, sizeof(*pdu));
if (err)
*err = NULL;
diff --git a/src/gsm/bssmap_le.c b/src/gsm/bssmap_le.c
index 3e90a43..1ee4551 100644
--- a/src/gsm/bssmap_le.c
+++ b/src/gsm/bssmap_le.c
@@ -180,7 +180,7 @@
struct osmo_bssmap_le_err **err, void *err_ctx,
const uint8_t *elem, uint8_t len)
{
- *lt = (struct bssmap_le_location_type){};
+ memset(lt, 0x00, sizeof(*lt));
if (!elem || len < 1)
DEC_ERR(-EINVAL, msgt, iei, LCS_CAUSE_UNSPECIFIED, "zero length");
@@ -348,7 +348,7 @@
struct osmo_bssmap_le_err **err, void *err_ctx,
const uint8_t *data, uint8_t len)
{
- *lcs_cause = (struct lcs_cause_ie){};
+ memset(lcs_cause, 0x00, sizeof(*lcs_cause));
if (!data || len < 1)
DEC_ERR(-EINVAL, msgt, iei, LCS_CAUSE_UNSPECIFIED, "zero length");
@@ -558,7 +558,7 @@
struct osmo_bssmap_le_err **err, void *err_ctx,
const struct tlv_parsed *tp)
{
- *params = (struct bssmap_le_perform_loc_req){};
+ memset(params, 0x00, sizeof(*params));
DEC_IE_MANDATORY(msgt, BSSMAP_LE_IEI_LOCATION_TYPE, osmo_bssmap_le_ie_dec_location_type,
¶ms->location_type);
@@ -606,7 +606,7 @@
struct osmo_bssmap_le_err **err, void *err_ctx,
const struct tlv_parsed *tp)
{
- *params = (struct bssmap_le_perform_loc_resp){};
+ memset(params, 0x00, sizeof(*params));
DEC_IE_OPTIONAL_FLAG(msgt, BSSMAP_LE_IEI_GEO_LOCATION, osmo_bssmap_le_ie_dec_gad, ¶ms->location_estimate,
params->location_estimate_present);
@@ -630,7 +630,7 @@
struct osmo_bssmap_le_err **err, void *err_ctx,
const struct tlv_parsed *tp)
{
- *params = (struct lcs_cause_ie){};
+ memset(params, 0x00, sizeof(*params));
DEC_IE_MANDATORY(msgt, BSSMAP_LE_IEI_LCS_CAUSE, osmo_lcs_cause_dec, params);
return 0;
@@ -647,7 +647,8 @@
struct osmo_bssmap_le_err **err, void *err_ctx,
const struct tlv_parsed *tp)
{
- *params = (struct bssmap_le_conn_oriented_info){};
+ memset(params, 0x00, sizeof(*params));
+
DEC_IE_MANDATORY(msgt, BSSMAP_LE_IEI_APDU, osmo_bssmap_le_ie_dec_apdu, ¶ms->apdu);
return 0;
}
@@ -711,7 +712,7 @@
int ies_len;
struct tlv_parsed tp;
- *pdu = (struct bssmap_le_pdu){};
+ memset(pdu, 0x00, sizeof(*pdu));
if (len < 1)
DEC_ERR(-EINVAL, -1, -1, LCS_CAUSE_UNSPECIFIED, "zero length");
@@ -798,7 +799,7 @@
return RC; \
} while(0)
- *pdu = (struct bssap_le_pdu){};
+ memset(pdu, 0x00, sizeof(*pdu));
h = msgb_l2(msg);
if (!h)