Fix buffer overflow in sdp_xml_parse_uuid128

This fixes a buffer overflow found by OSS-Fuzz. The ASan stacktrace for this is:

```
=================================================================
==402==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7c960dd00030 at pc 0x59331ced5b8d bp 0x7fffedcc0c50 sp 0x7fffedcc0c48
WRITE of size 1 at 0x7c960dd00030 thread T0
    #0 0x59331ced5b8c in sdp_xml_parse_uuid128 bluez/src/sdp-xml.c:128:17
    #1 0x59331ced5b8c in sdp_xml_parse_uuid bluez/src/sdp-xml.c:146:9
    #2 0x59331ced3529 in sdp_xml_parse_datatype bluez/src/sdp-xml.c:428:10
    #3 0x59331ced3529 in element_start bluez/src/sdp-xml.c:498:32
    #4 0x59331cf26628 in emit_start_element glib/glib/gmarkup.c:1010:5
    #5 0x59331cf258d7 in g_markup_parse_context_parse glib/glib/gmarkup.c:1369:17
    #6 0x59331ced1969 in sdp_xml_parse_record bluez/src/sdp-xml.c:621:6
    #7 0x59331ced8cc9 in LLVMFuzzerTestOneInput /src/fuzz_xml.c:30:9
    #8 0x59331ced1879 in ExecuteFilesOnyByOne /src/aflplusplus/utils/aflpp_driver/aflpp_driver.c:255:7
    #9 0x59331ced1675 in LLVMFuzzerRunDriver /src/aflplusplus/utils/aflpp_driver/aflpp_driver.c:0
    #10 0x59331ced122d in main /src/aflplusplus/utils/aflpp_driver/aflpp_driver.c:311:10
    #11 0x7c961015c082 in __libc_start_main /build/glibc-LcI20x/glibc-2.31/csu/libc-start.c:308:16
    #12 0x59331cdf8a2d in _start
```

Oliver Chang (1):
Fix buffer overflow in sdp_xml_parse_uuid128

 src/sdp-xml.c | 6 ++++++
 1 file changed, 6 insertions(+)

2.50.1.703.g449372360f-goog

This was found by OSS-Fuzz.

This can be reproduced by running this input:
<uuid value="111111111111111111111111111111111111"> against the harness in
https://github.com/google/oss-fuzz/blob/master/projects/bluez/fuzz_xml.c
which just calls sdp_xml_parse_record.

sdp_xml_parse_uuid checks that the length of the string is 36 (32 digits + 4 '-' characters) prior to calling sdp_xml_parse_uuid128.

There's no check preventing this data from being 36 digits (with no "-"), which leads to a buffer overflow in sdp_xml_parse_uuid128.

https://issues.oss-fuzz.com/issues/42534847
https://oss-fuzz.com/testcase-detail/5070205940531200

---
 src/sdp-xml.c | 6 ++++++
 1 file changed, 6 insertions(+)

index 5efa62ab8..2fa8f28a0 100644
@@ -125,10 +125,16 @@ static sdp_data_t *sdp_xml_parse_uuid128(const char *data)
 		buf[0] = data[i];
 		buf[1] = data[i + 1];
 
+		if (j >= sizeof(val.data))
+			return NULL;
+
 		val.data[j++] = strtoul(buf, 0, 16);
 		i += 2;
 	}
 
+	if (j != sizeof(val.data))
+		return NULL;
+
 	return sdp_data_alloc(SDP_UUID128, &val);
 }
 

2.50.1.703.g449372360f-goog

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list. This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=989676

---Test result---

Test Summary:

CheckPatch                    PENDING   0.32 seconds
GitLint                       PENDING   0.30 seconds
BuildEll                      PASS      20.05 seconds
BluezMake                     PASS      2604.83 seconds
MakeCheck                     PASS      19.93 seconds
MakeDistcheck                 PASS      183.97 seconds
CheckValgrind                 PASS      236.11 seconds
CheckSmatch                   PASS      304.70 seconds
bluezmakeextell               PASS      128.03 seconds
IncrementalBuild              PENDING   0.23 seconds
ScanBuild                     PASS      907.12 seconds

Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script
Output:

##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:

##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series Output:

---
Regards,
Linux Bluetooth