Daniel Borkmann b9c1e60e7b bpf, ppc64: fix unexpected r0=0 exit path inside bpf_xadd ... None of the JITs is allowed to implement exit paths from the BPF insn mappings other than BPF_JMP | BPF_EXIT. In the BPF core code we have a couple of rewrites in eBPF (e.g. LD_ABS / LD_IND) and in eBPF to cBPF translation to retain old existing behavior where exceptions may occur; they are also tightly controlled by the verifier where it disallows some of the features such as BPF to BPF calls when legacy LD_ABS / LD_IND ops are present in the BPF program. During recent review of all BPF_XADD JIT implementations I noticed that the ppc64 one is buggy in that it contains two jumps to exit paths. This is problematic as this can bypass verifier expectations e.g. pointed out in commit f6b1b3bf0d ("bpf: fix subprog verifier bypass by div/mod by 0 exception"). The first exit path is obsoleted by the fix in ca36960211 ("bpf: allow xadd only on aligned memory") anyway, and for the second one we need to do a fetch, add and store loop if the reservation from lwarx/ldarx was lost in the meantime. Fixes: 156d0e290e ("powerpc/ebpf/jit: Implement JIT compiler for extended BPF") Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-by: Sandipan Das <sandipan@linux.vnet.ibm.com> Tested-by: Sandipan Das <sandipan@linux.vnet.ibm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>		2018-07-19 16:08:06 -07:00
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Makefile	bpf, ppc64: remove ld_abs/ld_ind	2018-05-03 16:49:20 -07:00
bpf_jit.h	bpf, ppc64: implement jiting of BPF_J{LT, LE, SLT, SLE}	2017-08-09 16:53:57 -07:00
bpf_jit32.h	powerpc/bpf/jit: Isolate classic BPF JIT specifics into a separate header	2016-06-24 15:15:51 +10:00
bpf_jit64.h	bpf, ppc64: remove ld_abs/ld_ind	2018-05-03 16:49:20 -07:00
bpf_jit_asm.S	powerpc/bpf/jit: Isolate classic BPF JIT specifics into a separate header	2016-06-24 15:15:51 +10:00
bpf_jit_comp.c	treewide: kzalloc() -> kcalloc()	2018-06-12 16:19:22 -07:00
bpf_jit_comp64.c	bpf, ppc64: fix unexpected r0=0 exit path inside bpf_xadd	2018-07-19 16:08:06 -07:00