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Message-ID: <20230817135558.67274c83@imladris.surriel.com>
Date: Thu, 17 Aug 2023 13:55:58 -0400
From: Rik van Riel <riel@...riel.com>
To: linux-kernel@...r.kernel.org
Cc: kernel-team@...a.com, Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
Rob Herring <robh@...nel.org>
Subject: [PATCH] mm,kexec,ima,x86: use memblock_free_late from
ima_free_kexec_buffer
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@...nel.org
Signed-off-by: Rik van Riel <riel@...riel.com>
Suggested-by: Mike Rappoport <rppt@...nel.org>
---
arch/x86/kernel/setup.c | 8 ++------
1 file changed, 2 insertions(+), 6 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;
--
2.41.0
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