Hello, El lun, 24 may 2021 a las 17:26, Pablo Neira Ayuso (<pablo@xxxxxxxxxxxxx>) escribió: > > On Tue, May 18, 2021 at 08:17:30PM +0200, Thomas De Schampheleire wrote: > > From: Thomas De Schampheleire <thomas.de_schampheleire@xxxxxxxxx> > > > > The ebtables build system seems to assume that 'sparc64' is the > > only case where KERNEL_64_USERSPACE_32 is relevant, but this is not true. > > This situation can happen on many architectures, especially in embedded > > systems. For example, an Aarch64 processor with kernel in 64-bit but > > userland built for 32-bit Arm. Or a 64-bit MIPS Octeon III processor, with > > userland running in the 'n32' ABI. > > > > While it is possible to set CFLAGS in the environment when calling the > > configure script, the caller would need to know to not only specify > > KERNEL_64_USERSPACE_32 but also the EBT_MIN_ALIGN value. > > > > Instead, add a configure option. All internal details can then be handled by > > the configure script. > > Are you enabling > > CONFIG_NETFILTER_XTABLES_COMPAT > > in your kernel build? > > KERNEL_64_USERSPACE_32 was deprecated long time ago in favour of > CONFIG_NETFILTER_XTABLES_COMPAT. The option you refer to (CONFIG_NETFILTER_XTABLES_COMPAT) was introduced with commit 47a6959fa331fe892a4fc3b48ca08e92045c6bda (5.13-rc1). Before that point, it seems CONFIG_COMPAT was the relevant flag. The checks on CONFIG_COMPAT were already introduced with commit 81e675c227ec60a0bdcbb547dc530ebee23ff931 in 2.6.34.x. I have seen this problem on Linux 4.1 and 4.9, on an Aarch64 CPU with 64-bit kernel and userspace compiled as 32-bit ARM. In both kernels, CONFIG_COMPAT was set. So I am a bit surprised that I bump into this issue after upgrading ebtables from 2.0.10-4 to 2.0.11 where the padding was removed. According to your mail and the commits mentioned, it is supposed to work without ebtables making specific provisions for the 32/64 bit type difference. When I apply the patches I submitted to this list, I get correct behavior. Without them, the kernel complains and ebtables fails. Best regards, Thomas
