The code calling ima_free_kexec_buffer runs long after the memblock
allocator has already been torn down, potentially resulting in a use
after free in memblock_isolate_range.
With KASAN or KFENCE, this use after free will result in a BUG
from the idle task, and a subsequent kernel panic.
Switch ima_free_kexec_buffer over to memblock_free_late to avoid
that issue.
Fixes: fee3ff99bc67 ("powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c")
Cc: stable@xxxxxxxxxx
Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
Suggested-by: Mike Rappoport <rppt@xxxxxxxxxx>
---
arch/x86/kernel/setup.c | 8 ++------
drivers/of/kexec.c | 3 ++-
2 files changed, 4 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index fd975a4a5200..aa0df37c1fe7 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -359,15 +359,11 @@ static void __init add_early_ima_buffer(u64 phys_addr)
#if defined(CONFIG_HAVE_IMA_KEXEC) && !defined(CONFIG_OF_FLATTREE)
int __init ima_free_kexec_buffer(void)
{
- int rc;
-
if (!ima_kexec_buffer_size)
return -ENOENT;
- rc = memblock_phys_free(ima_kexec_buffer_phys,
- ima_kexec_buffer_size);
- if (rc)
- return rc;
+ memblock_free_late(ima_kexec_buffer_phys,
+ ima_kexec_buffer_size);
ima_kexec_buffer_phys = 0;
ima_kexec_buffer_size = 0;
diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index f26d2ba8a371..68278340cecf 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c
@@ -184,7 +184,8 @@ int __init ima_free_kexec_buffer(void)
if (ret)
return ret;
- return memblock_phys_free(addr, size);
+ memblock_free_late(addr, size);
+ return 0;
}
#endif
--
2.41.0
