6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Rik van Riel <riel@xxxxxxxxxxx>
commit f0362a253606e2031f8d61c74195d4d6556e12a4 upstream.
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>
Link: https://lore.kernel.org/r/20230817135759.0888e5ef@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/of/kexec.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- 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
