Coverity scan error - Out-of-bounds write (OVERRUN)- in sha512.c file

[sarigavs-jeppesen]

Getting error CID 239935: (#1 of 1): Out-of-bounds write (OVERRUN) , overrun-local: Overrunning array md->buf of 128 bytes at byte offset 128 using index i + md->curlen (which evaluates to 128). ' in sha512.c file while running Coverity scan tool.

Find the below code with comments(in bold) from Coverity tool.

int sha512_update (sha512_context * md, const unsigned char *in, size_t inlen)
172{
173 size_t n;
174 size_t i;
175 int err;
1. Condition md == NULL, taking false branch.
176 if (md == NULL) return 1;
2. Condition in == NULL, taking false branch.
177 if (in == NULL) return 1;
3. Condition md->curlen > 128UL / sizeof (md->buf) /, taking false branch.
4. cond_at_most: Checking md->curlen > 128UL implies that md->curlen may be up to 128 on the false branch.
178 if (md->curlen > sizeof(md->buf)) {
179 return 1;
180 }
5. Condition inlen > 0, taking true branch.
181 while (inlen > 0) {
6. Condition md->curlen == 0, taking false branch.
7. cond_between: Checking md->curlen == 0UL implies that md->curlen is between 1 and 128 (inclusive) on the false branch.
182 if (md->curlen == 0 && inlen >= 128) {
183 if ((err = sha512_compress (md, (unsigned char *)in)) != 0) {
184 return err;
185 }
186 md->length += 128 * 8;
187 in += 128;
188 inlen -= 128;
189 } else {
8. Condition inlen < 128 - md->curlen, taking true branch.
190 n = MIN(inlen, (128 - md->curlen));
191
9. assignment: Assigning: i = 0UL.
10. Condition i < n, taking true branch.
192 for (i = 0; i < n; i++) {

CID 239935: (#1 of 1): Out-of-bounds write (OVERRUN)
11. overrun-local: Overrunning array md->buf of 128 bytes at byte offset 128 using index i + md->curlen (which evaluates to 128).
193 md->buf[i + md->curlen] = in[i];
194 }
195
196
197 md->curlen += n;
198 in += n;
199 inlen -= n;
200 if (md->curlen == 128) {
201 if ((err = sha512_compress (md, md->buf)) != 0) {
202 return err;
203 }
204 md->length += 8*128;
205 md->curlen = 0;
206 }
207 }
208 }
209 return 0;
210}
211