Fix array overrun and asprintf() usage, with other warnings.

The array overrun crashed Win32, the asprintf() usage imacts glibc
and the other warnings are impossible (an exception would have been
thrown).

src/sbbs3/sftp.cpp

@@ -206,7 +206,7 @@ public:
 			this->info.filebase.lib = -1;
 			this->info.filebase.idx = dot;
 			char *lib;
-			size_t sz;
+			size_t sz{files_path_len}; // Initialize in case tree_ isn't valid (which should have trown an exception)
 			switch (tree_) {
 				case SFTP_DTREE_FULL:
 					sz = files_path_len;
@@ -265,8 +265,7 @@ public:
 			smbfile_t file{};
 			result_ = MAP_TO_FILE;
 			const char *fname = &dir[dirsz + 1];
-			asprintf(&this->local_path, "%s/%s", sbbs->cfg.dir[this->info.filebase.dir]->path, fname);
-			if (this->local_path == nullptr) {
+			if (asprintf(&this->local_path, "%s/%s", sbbs->cfg.dir[this->info.filebase.dir]->path, fname) == -1) {
 				result_ = MAP_ALLOC_FAILED;
 				return;
 			}
@@ -324,8 +323,7 @@ public:
 				    || (tmpdir[pathlen] == '/' && tmpdir[pathlen + 1] == 0))) {
 					this->info.rootdir.mapping = &static_files[sfidx];
 					if (static_files[sfidx].real_patt) {
-						asprintf(&this->local_path, static_files[sfidx].real_patt, sbbs->cfg.data_dir, sbbs->useron.number);
-						if (this->local_path == nullptr) {
+						if (asprintf(&this->local_path, static_files[sfidx].real_patt, sbbs->cfg.data_dir, sbbs->useron.number) == -1) {
 							result_ = MAP_ALLOC_FAILED;
 							return;
 						}
@@ -341,8 +339,7 @@ public:
 						}
 					}
 					if (static_files[sfidx].link_patt) {
-						asprintf(&this->sftp_link_target, static_files[sfidx].link_patt, sbbs->useron.alias);
-						if (this->local_path == nullptr) {
+						if (asprintf(&this->sftp_link_target, static_files[sfidx].link_patt, sbbs->useron.alias) == -1) {
 							result_ = MAP_ALLOC_FAILED;
 							return;
 						}
@@ -693,13 +690,14 @@ sftp_parse_crealpath(sbbs_t *sbbs, const char *filename)
 	char *ret;
 	char *tmp;
 
-	if (sbbs->sftp_cwd == nullptr)
-		asprintf(&sbbs->sftp_cwd, SLASH_HOME "/%s", sbbs->useron.alias);
+	if (sbbs->sftp_cwd == nullptr) {
+		if (asprintf(&sbbs->sftp_cwd, SLASH_HOME "/%s", sbbs->useron.alias) == -1)
+			sbbs->sftp_cwd = nullptr;
+	}
 	if (sbbs->sftp_cwd == nullptr)
 		return nullptr;
 	if (!isfullpath(filename)) {
-		asprintf(&tmp, "%s/%s", sbbs->sftp_cwd, filename);
-		if (tmp == nullptr)
+		if (asprintf(&tmp, "%s/%s", sbbs->sftp_cwd, filename) == -1)
 			return tmp;
 		ret = sftp_resolve_path(nullptr, tmp, 0);
 		free(tmp);
@@ -892,7 +890,8 @@ get_longname(sbbs_t *sbbs, const char *path, const char *link, sftp_file_attr_t
 	fname = getfname(path);
 	if (fname[0] == 0)
 		fname = path;
-	asprintf(&ret, "%s   0 %-8.8s %-8.8s %-8s %-12s %s%s%s", pstr, owner, group, szstr, datestr, fname, pstr[0] == 'l' ? " -> " : "", link ? link : "");
+	if (asprintf(&ret, "%s   0 %-8.8s %-8.8s %-8s %-12s %s%s%s", pstr, owner, group, szstr, datestr, fname, pstr[0] == 'l' ? " -> " : "", link ? link : "") == -1)
+		return nullptr;
 	return ret;
 }
 
@@ -1090,6 +1089,8 @@ get_attrs(sbbs_t *sbbs, const char *path, char **link)
 			case SFTP_DTREE_VIRTUAL:
 				libp = path + vfiles_path_len + 1;
 				break;
+			default:
+				return nullptr;
 		}
 		lib = find_lib(sbbs, libp, tree);
 		if (lib == -1) {
@@ -1127,8 +1128,7 @@ get_attrs(sbbs_t *sbbs, const char *path, char **link)
 		ppath[0] = 0;
 	ret = pm->get_attrs(sbbs, ppath);
 	if (link && pm->link_patt) {
-		asprintf(link, pm->link_patt, sbbs->useron.alias);
-		if (link == nullptr) {
+		if (asprintf(link, pm->link_patt, sbbs->useron.alias) == -1) {
 			sftp_fattr_free(ret);
 			ret = nullptr;
 		}
@@ -1333,7 +1333,7 @@ sftp_open(sftp_str_t filename, uint32_t flags, sftp_file_attr_t attributes, void
 			oflags |= O_RDWR;
 			mmode = MAP_RDWR;
 			break;
-		case 0:
+		default:
 			return sftps_send_error(sbbs->sftp_state, SSH_FX_OP_UNSUPPORTED, "Invalid flags (not read or write)");
 	}
 	if (flags & SSH_FXF_APPEND)
@@ -1654,6 +1654,8 @@ sftp_readdir(sftp_dirhandle_t handle, void *cb_data)
 		copy_path(cwd, pm->sftp_patt);
 		while (static_files[dd->info.rootdir.idx].sftp_patt != nullptr && fn.entries() < MAX_FILES_PER_READDIR) {
 			dd->info.rootdir.idx++;
+			if (dd->info.rootdir.idx >= static_files_sz)
+				break;
 			if (static_files[dd->info.rootdir.idx].sftp_patt == nullptr) {
 				dd->info.rootdir.idx = no_more_files;
 				if (fn.entries() > 0)
@@ -1813,6 +1815,9 @@ sftp_readdir(sftp_dirhandle_t handle, void *cb_data)
 					case SFTP_DTREE_VIRTUAL:
 						ename = expand_slash(sbbs->cfg.dir[dd->info.filebase.idx]->vdir);
 						break;
+					default:
+						sftp_fattr_free(attr);
+						return sftps_send_error(sbbs->sftp_state, SSH_FX_FAILURE, "Invalid tree type");
 				}
 				if (ename == nullptr) {
 					sftp_fattr_free(attr);