6.5-stable review patch. If anyone has any objections, please let me know.
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From: Rik van Riel riel@surriel.com
[ Upstream commit 34cf99c250d5cd2530b93a57b0de31d3aaf8685b ]
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 bug.
Fixes: fee3ff99bc67 ("powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c") Suggested-by: Mike Rappoport rppt@kernel.org Signed-off-by: Rik van Riel riel@surriel.com Signed-off-by: Ingo Molnar mingo@kernel.org Link: https://lore.kernel.org/r/20230817135558.67274c83@imladris.surriel.com Signed-off-by: Sasha Levin sashal@kernel.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 fd975a4a52006..aa0df37c1fe72 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;