rtdl: Return null when non-elf file is dlopened

managarm · Aug 18, 2023 · f3d15f1 · f3d15f1
1 parent 67bee48
commit f3d15f1
Showing 1 changed file with 29 additions and 0 deletions.
diff --git a/options/rtdl/generic/linker.cpp b/options/rtdl/generic/linker.cpp
@@ -249,6 +249,20 @@ SharedObject *ObjectRepository::requestObjectWithName(frg::string_view name,
 	auto object = frg::construct<SharedObject>(getAllocator(),
 		name.data(), std::move(chosenPath), false, localScope, rts);
 
+	Elf64_Ehdr hdr;
+
+	ssize_t dumb = 0;
+	mlibc::sys_read(fd, &hdr, sizeof(Elf64_Ehdr), &dumb);
+	if (dumb != sizeof(Elf64_Ehdr)
+			|| (hdr.e_ident[0] != 0x7F || hdr.e_ident[1] != 'E' || hdr.e_ident[2] != 'L' || hdr.e_ident[3] != 'F')) {
+		closeOrDie(fd);
+		return nullptr;
+	}
+	if(mlibc::sys_seek(fd, 0, SEEK_SET, &dumb) != 0) {
+		closeOrDie(fd);
+		return nullptr;
+	}
+
 	_fetchFromFile(object, fd);
 	closeOrDie(fd);
 
@@ -288,6 +302,21 @@ SharedObject *ObjectRepository::requestObjectAtPath(frg::string_view path,
 	int fd;
 	if(mlibc::sys_open((no_prefix + '\0').data(), O_RDONLY, 0, &fd))
 		return nullptr; // TODO: Free the SharedObject.
+
+	Elf64_Ehdr hdr;
+
+	ssize_t dumb = 0;
+	mlibc::sys_read(fd, &hdr, sizeof(Elf64_Ehdr), &dumb);
+	if (dumb != sizeof(Elf64_Ehdr)
+			|| (hdr.e_ident[0] != 0x7F || hdr.e_ident[1] != 'E' || hdr.e_ident[2] != 'L' || hdr.e_ident[3] != 'F')) {
+		closeOrDie(fd);
+		return nullptr;
+	}
+	if(mlibc::sys_seek(fd, 0, SEEK_SET, &dumb) != 0) {
+		closeOrDie(fd);
+		return nullptr;
+	}
+
 	_fetchFromFile(object, fd);
 	closeOrDie(fd);