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SubjectRe: [PATCH] livepatch: x86: bugfix about kASLR
Zhou Chengming wrote:
> When enable KASLR, func->old_addr will be set to zero
> and livepatch will find the right old address.
> But for reloc, livepatch just verify it using reloc->val
> (old addr from user), so verify failed and report
> "kernel mismatch" error.
>
> Reported-by: Cyril B.<cbay@alwaysdata.com>
> Signed-off-by: Zhou Chengming<zhouchengming1@huawei.com>
> ---
> kernel/livepatch/core.c | 7 ++++++-
> 1 files changed, 6 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index 53196e2..c8885c6 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -311,7 +311,12 @@ static int klp_write_object_relocations(struct module *pmod,
> return -EINVAL;
>
> for (reloc = obj->relocs; reloc->name; reloc++) {
> - if (!klp_is_module(obj)) {
> +
> +#if defined(CONFIG_RANDOMIZE_BASE)
> + /* KASLR is enabled, disregard old_addr from user */
> + reloc->val = 0;
> +#endif
> + if (reloc->val&& !klp_is_module(obj)) {
> ret = klp_verify_vmlinux_symbol(reloc->name,
> reloc->val);
> if (ret)

I still get the 'symbol not found in symbol table' error with that patch
(on top of Linux 4.3).

Cyril


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