Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d92a2562 authored by Anton Gusev's avatar Anton Gusev Committed by Greg Kroah-Hartman
Browse files

efi: fix potential NULL deref in efi_mem_reserve_persistent 



[ Upstream commit 966d47e1f27c45507c5df82b2a2157e5a4fd3909 ]

When iterating on a linked list, a result of memremap is dereferenced
without checking it for NULL.

This patch adds a check that falls back on allocating a new page in
case memremap doesn't succeed.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 18df7577 ("efi/memreserve: deal with memreserve entries in unmapped memory")
Signed-off-by: default avatarAnton Gusev <aagusev@ispras.ru>
[ardb: return -ENOMEM instead of breaking out of the loop]
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent ed6c5e8c

drivers/firmware/efi/efi.c

+2 −0
Original line number Diff line number Diff line
@@ -1022,6 +1022,8 @@ 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; ) {

		rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB);

		if (!rsv)

			return -ENOMEM;

		index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);

		if (index < rsv->size) {

			rsv->entry[index].base = addr;