From: Anton Gusev aagusev@ispras.ru
[ 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: 18df7577adae ("efi/memreserve: deal with memreserve entries in unmapped memory") Signed-off-by: Anton Gusev aagusev@ispras.ru [ardb: return -ENOMEM instead of breaking out of the loop] 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 033aac6be7da..b43e5e6ddaf6 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -984,6 +984,8 @@ 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;