tlv_parser: Fix various out-of-bounds accesses
The libosmocore TLV parser had a number of insufficient bounds checks
leading to reads beyond the end of the respective input buffer.
This patch
* adds proper out-of-bounds checks to all TLV types
* simplifies some of the existing checks
* introduces test cases to test all the corner cases
where either TAG, or length, or value are not fully contained
in the input buffer.
Thanks to Ilja Van Sprundel for reporting these problems.
Change-Id: I98b02c914c9e3ecf56050af846292aa6979d7508
diff --git a/tests/tlv/tlv_test.c b/tests/tlv/tlv_test.c
index 925d762..3b4f441 100644
--- a/tests/tlv/tlv_test.c
+++ b/tests/tlv/tlv_test.c
@@ -332,6 +332,97 @@
msgb_free(msg);
}
+static void test_tlv_parser_bounds()
+{
+ struct tlv_definition tdef;
+ struct tlv_parsed dec;
+ uint8_t buf[32];
+
+ memset(&tdef, 0, sizeof(tdef));
+
+ printf("Testing TLV_TYPE_T decoder for out-of-bounds\n");
+ tdef.def[0x23].type = TLV_TYPE_T;
+ buf[0] = 0x23;
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 1, 0, 0) == 1);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 0, 0, 0) == 0);
+
+ printf("Testing TLV_TYPE_TV decoder for out-of-bounds\n");
+ tdef.def[0x23].type = TLV_TYPE_TV;
+ buf[0] = 0x23;
+ buf[1] = 0x42;
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 2, 0, 0) == 1);
+ OSMO_ASSERT(*TLVP_VAL(&dec, 0x23) == buf[1]);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 1, 0, 0) == OSMO_TLVP_ERR_OFS_LEN_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+
+ printf("Testing TLV_TYPE_FIXED decoder for out-of-bounds\n");
+ tdef.def[0x23].type = TLV_TYPE_FIXED;
+ tdef.def[0x23].fixed_len = 2;
+ buf[0] = 0x23;
+ buf[1] = 0x42;
+ buf[2] = 0x55;
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 3, 0, 0) == 1);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 2, 0, 0) == OSMO_TLVP_ERR_OFS_LEN_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+
+ printf("Testing TLV_TYPE_TLV decoder for out-of-bounds\n");
+ tdef.def[0x23].type = TLV_TYPE_TLV;
+ buf[0] = 0x23;
+ buf[1] = 0x02;
+ buf[2] = 0x55;
+ buf[3] = 0xAA;
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 4, 0, 0) == 1);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == &buf[2]);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 3, 0, 0) == OSMO_TLVP_ERR_OFS_LEN_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 2, 0, 0) == OSMO_TLVP_ERR_OFS_LEN_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 1, 0, 0) == OSMO_TLVP_ERR_OFS_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+
+ printf("Testing TLV_TYPE_vTvLV_GAN decoder for out-of-bounds\n");
+ tdef.def[0x23].type = TLV_TYPE_vTvLV_GAN;
+ buf[0] = 0x23;
+ buf[1] = 0x80;
+ buf[2] = 0x01;
+ buf[3] = 0xAA;
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 4, 0, 0) == 1);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == &buf[3]);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 3, 0, 0) == OSMO_TLVP_ERR_OFS_LEN_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 2, 0, 0) == OSMO_TLVP_ERR_OFS_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 1, 0, 0) == OSMO_TLVP_ERR_OFS_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+
+ printf("Testing TLV_TYPE_TvLV decoder for out-of-bounds\n");
+ tdef.def[0x23].type = TLV_TYPE_TvLV;
+ buf[0] = 0x23;
+ buf[1] = 0x81;
+ buf[2] = 0xAA;
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 3, 0, 0) == 1);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == &buf[2]);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 2, 0, 0) == OSMO_TLVP_ERR_OFS_LEN_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 1, 0, 0) == OSMO_TLVP_ERR_OFS_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+
+ printf("Testing TLV_TYPE_TL16V decoder for out-of-bounds\n");
+ tdef.def[0x23].type = TLV_TYPE_TL16V;
+ buf[0] = 0x23;
+ buf[1] = 0x00;
+ buf[2] = 0x01;
+ buf[3] = 0xAA;
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 4, 0, 0) == 1);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == &buf[3]);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 3, 0, 0) == OSMO_TLVP_ERR_OFS_LEN_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 2, 0, 0) == OSMO_TLVP_ERR_OFS_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+ OSMO_ASSERT(tlv_parse(&dec, &tdef, buf, 1, 0, 0) == OSMO_TLVP_ERR_OFS_BEYOND_BUFFER);
+ OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
+}
+
int main(int argc, char **argv)
{
//osmo_init_logging2(ctx, &info);
@@ -339,6 +430,7 @@
test_tlv_shift_functions();
test_tlv_repeated_ie();
test_tlv_encoder();
+ test_tlv_parser_bounds();
printf("Done.\n");
return EXIT_SUCCESS;