[PATCH 5.10 155/157] firmware/efi: Fix a use after bug in efi_mem_reserve_persistent
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-03-22 12:54:14
Also in:
lkml
From: Lv Yunlong <redacted>
commit 9ceee7d0841a8f7d7644021ba7d4cc1fbc7966e3 upstream.
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 <redacted>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/firmware/efi/efi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c@@ -927,7 +927,7 @@ int __ref efi_mem_reserve_persistent(phy } /* 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(phy memunmap(rsv); return efi_mem_reserve_iomem(addr, size); } + prsv = rsv->next; memunmap(rsv); }