efi/libstub: Handle NULL cmdline

commit a37ca6a2af9df2972372b918f09390c9303acfbd upstream.

Treat a NULL cmdline the same as empty. Although this is unlikely to
happen in practice, the x86 kernel entry does check for NULL cmdline and
handles it, so do it here as well.

Cc: <stable@vger.kernel.org>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200729193300.598448-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 581367482d2e11788e9b9312596e2314b56df56d..cac64fdfc3ae45ceda96bf875b45dca3dd6e40ed 100644 (file)
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -73,10 +73,14 @@ void efi_printk(char *str)
  */
 efi_status_t efi_parse_options(char const *cmdline)
 {
-       size_t len = strlen(cmdline) + 1;
+       size_t len;
        efi_status_t status;
        char *str, *buf;
 
+       if (!cmdline)
+               return EFI_SUCCESS;
+
+       len = strlen(cmdline) + 1;
        status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, len, (void **)&buf);
        if (status != EFI_SUCCESS)
                return status;