[PATCH 6.6 303/396] efi: fix panic in kdump kernel

Greg Kroah-Hartman
2024-04-01T16:51:46Z

From: Oleksandr Tymoshenko <ovt@google.com>

[ Upstream commit 62b71cd73d41ddac6b1760402bbe8c4932e23531 ]

Check if get_next_variable() is actually valid pointer before
calling it. In kdump kernel this method is set to NULL that causes
panic during the kexec-ed kernel boot.

Tested with QEMU and OVMF firmware.

Fixes: bad267f9e18f ("efi: verify that variable services are supported")
Signed-off-by: Oleksandr Tymoshenko <ovt@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/firmware/efi/efi.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 1974f0ad32bad..2c1095dcc2f2f 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -199,6 +199,8 @@ static bool generic_ops_supported(void)

name_size = sizeof(name);

+ if (!efi.get_next_variable)
+ return false;
status = efi.get_next_variable(&name_size, &name, &guid);
if (status == EFI_UNSUPPORTED)
return false;
--
2.43.0