From 483028edacab374060d93955382b4865a9e07cba Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Wed, 17 Mar 2021 14:36:06 +0800 Subject: efivars: respect EFI_UNSUPPORTED return from firmware As per UEFI spec 2.8B section 8.2, EFI_UNSUPPORTED may be returned by EFI variable runtime services if no variable storage is supported by firmware. In this case, there is no point for kernel to continue efivars initialization. That said, efivar_init() should fail by returning an error code, so that efivarfs will not be mounted on /sys/firmware/efi/efivars at all. Otherwise, user space like efibootmgr will be confused by the EFIVARFS_MAGIC seen there, while EFI variable calls cannot be made successfully. Cc: # v5.10+ Signed-off-by: Shawn Guo Acked-by: Ard Biesheuvel Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/vars.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/firmware') diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index 41c1d00bf933..abdc8a6a3963 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -484,6 +484,10 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), } } + break; + case EFI_UNSUPPORTED: + err = -EOPNOTSUPP; + status = EFI_NOT_FOUND; break; case EFI_NOT_FOUND: break; -- cgit v1.2.3 From 9ceee7d0841a8f7d7644021ba7d4cc1fbc7966e3 Mon Sep 17 00:00:00 2001 From: Lv Yunlong Date: Wed, 10 Mar 2021 00:31:27 -0800 Subject: firmware/efi: Fix a use after bug in efi_mem_reserve_persistent In the for loop in efi_mem_reserve_persistent(), prsv = rsv->next use the unmapped rsv. Use the unmapped pages will cause segment fault. Fixes: 18df7577adae6 ("efi/memreserve: deal with memreserve entries in unmapped memory") Signed-off-by: Lv Yunlong Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/efi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/firmware') diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index df3f9bcab581..4b7ee3fa9224 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -927,7 +927,7 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) } /* first try to find a slot in an existing linked list entry */ - for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) { + for (prsv = efi_memreserve_root->next; prsv; ) { rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB); index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size); if (index < rsv->size) { @@ -937,6 +937,7 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) memunmap(rsv); return efi_mem_reserve_iomem(addr, size); } + prsv = rsv->next; memunmap(rsv); } -- cgit v1.2.3