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authorHarald Welte <laforge@gnumonks.org>2019-01-20 13:45:31 +0100
committerHarald Welte <laforge@gnumonks.org>2019-01-22 14:53:54 +0000
commit2033be8902f5540f4f0e28bf1b32fb7df0367c66 (patch)
treec7b08b1d2993b77fb5f63ce37e8d897ccc6acc52
parent1c3bae138cea1dbde480ce4382120034eb769e82 (diff)
Work around bogus gcc-8.2 array-bounds warning/error
gcc-8.2 is printing the following warning, which is an error when used -Werror like our --enable-werror: In file included from gprs_bssgp.c:34: In function ‘tl16v_put’, inlined from ‘tvlv_put.part.3’ at ../../include/osmocom/gsm/tlv.h:156:9, inlined from ‘tvlv_put’ at ../../include/osmocom/gsm/tlv.h:147:24, inlined from ‘msgb_tvlv_push’ at ../../include/osmocom/gsm/tlv.h:386:2, inlined from ‘bssgp_tx_dl_ud’ at gprs_bssgp.c:1162:4: ../../include/osmocom/gsm/tlv.h:131:2: error: ‘memcpy’ forming offset [12, 130] is out of the bounds [0, 11] of object ‘mi’ with type ‘uint8_t[11]’ {aka ‘unsigned char[11]’} [-Werror=array-bounds] memcpy(buf, val, len); Where "130" seems to be the maximum value of uint8_t, shifted right one + 2. But even as we use strnlen() with "16" as maximum upper bound, gcc still believes there's a way that the return value of gsm48_generate_mid_from_imsi() could be 130. In fact, even the newly-added OSMO_ASSERT() inside gsm48_generate_mid() doesn't help and gcc still insists there is a problem :( Change-Id: I0a06daa19b7b5b5badbb8b3d81a54c45b88a60ec
-rw-r--r--src/gb/gprs_bssgp.c14
-rw-r--r--src/gb/gprs_bssgp_bss.c8
2 files changed, 21 insertions, 1 deletions
diff --git a/src/gb/gprs_bssgp.c b/src/gb/gprs_bssgp.c
index be7ef9f..4a4bab3 100644
--- a/src/gb/gprs_bssgp.c
+++ b/src/gb/gprs_bssgp.c
@@ -1157,10 +1157,17 @@ int bssgp_tx_dl_ud(struct msgb *msg, uint16_t pdu_lifetime,
/* IMSI */
if (dup->imsi && strlen(dup->imsi)) {
uint8_t mi[GSM48_MID_MAX_SIZE];
+/* gsm48_generate_mid_from_imsi() is guaranteed to never return more than 11,
+ * but somehow gcc (8.2) is not smart enough to figure this out and claims that
+ * the memcpy in msgb_tvlv_put() below will cause and out-of-bounds access up to
+ * mi[131], which is wrong */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Warray-bounds"
int imsi_len = gsm48_generate_mid_from_imsi(mi, dup->imsi);
if (imsi_len > 2)
msgb_tvlv_push(msg, BSSGP_IE_IMSI,
imsi_len-2, mi+2);
+#pragma GCC diagnostic pop
}
/* DRX parameters */
@@ -1220,7 +1227,14 @@ int bssgp_tx_paging(uint16_t nsei, uint16_t ns_bvci,
else
bgph->pdu_type = BSSGP_PDUT_PAGING_CS;
/* IMSI */
+/* gsm48_generate_mid_from_imsi() is guaranteed to never return more than 11,
+ * but somehow gcc (8.2) is not smart enough to figure this out and claims that
+ * the memcpy in msgb_tvlv_put() below will cause and out-of-bounds access up to
+ * mi[131], which is wrong */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Warray-bounds"
msgb_tvlv_put(msg, BSSGP_IE_IMSI, imsi_len-2, mi+2);
+#pragma GCC diagnostic pop
/* DRX Parameters */
msgb_tvlv_put(msg, BSSGP_IE_DRX_PARAMS, 2,
(uint8_t *) &drx_params);
diff --git a/src/gb/gprs_bssgp_bss.c b/src/gb/gprs_bssgp_bss.c
index 77350e2..bef9bb1 100644
--- a/src/gb/gprs_bssgp_bss.c
+++ b/src/gb/gprs_bssgp_bss.c
@@ -183,10 +183,16 @@ int bssgp_tx_radio_status_imsi(struct bssgp_bvc_ctx *bctx, uint8_t cause,
if (!msg)
return -ENOMEM;
-
+/* gsm48_generate_mid_from_imsi() is guaranteed to never return more than 11,
+ * but somehow gcc (8.2) is not smart enough to figure this out and claims that
+ * the memcpy in msgb_tvlv_put() below will cause and out-of-bounds access up to
+ * mi[131], which is wrong */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Warray-bounds"
/* strip the MI type and length values (2 bytes) */
if (imsi_len > 2)
msgb_tvlv_put(msg, BSSGP_IE_IMSI, imsi_len-2, mi+2);
+#pragma GCC diagnostic pop
LOGPC(DBSSGP, LOGL_NOTICE, "IMSI=%s ", imsi);
return common_tx_radio_status2(msg, cause);