Messages in this thread | | | Date | Wed, 04 Nov 2015 13:27:33 +0100 | From | "Cyril B." <> | Subject | Re: [PATCH] livepatch: x86: bugfix about kASLR |
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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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