diff options
| author | Jakub Kicinski <jakub.kicinski@netronome.com> | 2017-10-23 11:58:13 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-24 17:38:37 +0900 |
| commit | b14157eeed4eff2b293e0ca7738f6a3dbfff51cc (patch) | |
| tree | 058eb11cfc701cf182a17b1259de1868934cf419 /drivers/net/ethernet/netronome/nfp/bpf/verifier.c | |
| parent | 2df03a50f14ab6d888c212aa332536933ded040a (diff) | |
nfp: bpf: support stack accesses via non-constant pointers
If stack pointer has a different value on different paths
but the alignment to words (4B) remains the same, we can
set a new LMEM access pointer to the calculated value and
access whichever word it's pointing to.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/netronome/nfp/bpf/verifier.c')
| -rw-r--r-- | drivers/net/ethernet/netronome/nfp/bpf/verifier.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c index 633db3e1a11e..3d3dcac1c942 100644 --- a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c +++ b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c @@ -112,7 +112,8 @@ nfp_bpf_check_exit(struct nfp_prog *nfp_prog, } static int -nfp_bpf_check_stack_access(struct nfp_insn_meta *meta, +nfp_bpf_check_stack_access(struct nfp_prog *nfp_prog, + struct nfp_insn_meta *meta, const struct bpf_reg_state *reg) { s32 old_off, new_off; @@ -128,7 +129,12 @@ nfp_bpf_check_stack_access(struct nfp_insn_meta *meta, old_off = meta->ptr.off + meta->ptr.var_off.value; new_off = reg->off + reg->var_off.value; - if (old_off == new_off) + meta->ptr_not_const |= old_off != new_off; + + if (!meta->ptr_not_const) + return 0; + + if (old_off % 4 == new_off % 4) return 0; pr_info("stack access changed location was:%d is:%d\n", @@ -151,7 +157,7 @@ nfp_bpf_check_ptr(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta, } if (reg->type == PTR_TO_STACK) { - err = nfp_bpf_check_stack_access(meta, reg); + err = nfp_bpf_check_stack_access(nfp_prog, meta, reg); if (err) return err; } |