criu: fix leaks detected by coverity scan

1) fix sfle memory leak on get_fle_for_scm error
2) fix gfd open descriptor leak on get_fle_for_scm error
3-6) fix buf memory leak on read and pwrite errors
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>

criu/files-reg.c

@@ -166,7 +166,6 @@ static int copy_chunk_from_file(int fd, int img, off_t off, size_t len)
 	}
 
 	xfree(buf);
-
 	return 0;
 }
 
@@ -231,7 +230,6 @@ static int copy_chunk_to_file(int img, int fd, off_t off, size_t len)
 	}
 
 	xfree(buf);
-
 	return 0;
 }
 
@@ -268,6 +266,7 @@ static int mkreg_ghost(char *path, GhostFileEntry *gfe, struct cr_img *img)
 	if (gfe->chunks) {
 		if (!gfe->has_size) {
 			pr_err("Corrupted ghost image -> no size\n");
+			close(gfd);
 			return -1;
 		}
 

criu/sk-unix.c

@@ -1055,6 +1055,7 @@ int unix_note_scm_rights(int id_for, uint32_t *file_ids, int *fds, int n_ids)
 		sfle->fle = get_fle_for_task(tgt, owner, false);
 		if (!sfle->fle) {
 			pr_err("Can't request new fle for scm\n");
+			xfree(sfle);
 			return -1;
 		}