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authorJakub Kicinski <jakub.kicinski@netronome.com>2016-09-21 12:43:59 +0200
committerDavid S. Miller <davem@davemloft.net>2016-09-22 01:50:02 +0200
commit6b17387307bafc71624b9890b9239b6a438e2e89 (patch)
tree7aca8f20e9bb67b803f70ae60cda1f53b397d325 /kernel/bpf
parentbpf: enable non-core use of the verfier (diff)
downloadlinux-6b17387307bafc71624b9890b9239b6a438e2e89.tar.xz
linux-6b17387307bafc71624b9890b9239b6a438e2e89.zip
bpf: recognize 64bit immediate loads as consts
When running as parser interpret BPF_LD | BPF_IMM | BPF_DW instructions as loading CONST_IMM with the value stored in imm. The verifier will continue not recognizing those due to concerns about search space/program complexity increase. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/verifier.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ee86a77dc40b..8c3f794c7028 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1769,9 +1769,19 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
if (err)
return err;
- if (insn->src_reg == 0)
- /* generic move 64-bit immediate into a register */
+ if (insn->src_reg == 0) {
+ /* generic move 64-bit immediate into a register,
+ * only analyzer needs to collect the ld_imm value.
+ */
+ u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
+
+ if (!env->analyzer_ops)
+ return 0;
+
+ regs[insn->dst_reg].type = CONST_IMM;
+ regs[insn->dst_reg].imm = imm;
return 0;
+ }
/* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */
BUG_ON(insn->src_reg != BPF_PSEUDO_MAP_FD);