arm64: kexec_file: handle empty command-line

Jean-Philippe Brucker · wildea01 · commit ea5736805190 · 2019-02-05T09:34:49.000Z
Calling strlen() on cmdline == NULL produces a kernel oops. Since having a NULL cmdline is valid, handle this case explicitly. Fixes: 52b2a8a ("arm64: kexec_file: load initrd and device-tree") Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
@@ -120,10 +120,12 @@ static int create_dtb(struct kimage *image,
 {
 	void *buf;
 	size_t buf_size;
+	size_t cmdline_len;
 	int ret;
 
+	cmdline_len = cmdline ? strlen(cmdline) : 0;
 	buf_size = fdt_totalsize(initial_boot_params)
-			+ strlen(cmdline) + DTB_EXTRA_SPACE;
+			+ cmdline_len + DTB_EXTRA_SPACE;
 
 	for (;;) {
 		buf = vmalloc(buf_size);
