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Commit 32bf08a6 authored Oct 20, 2014 by Alexei Starovoitov Committed by David S. Miller Oct 21, 2014

bpf: fix bug in eBPF verifier



while comparing for verifier state equivalency the comparison
was missing a check for uninitialized register.
Make sure it does so and add a testcase.

Fixes: f1bca824 ("bpf: add search pruning optimization to verifier")
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 78fd1d0a

kernel/bpf/verifier.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1409,7 +1409,8 @@ static bool states_equal(struct verifier_state old, struct verifier_state cur)
		if (memcmp(&old->regs[i], &cur->regs[i],
		sizeof(old->regs[0])) != 0) {
		if (old->regs[i].type == NOT_INIT \|\|
		old->regs[i].type == UNKNOWN_VALUE)
		(old->regs[i].type == UNKNOWN_VALUE &&
		cur->regs[i].type != NOT_INIT))
		continue;
		return false;
		}

samples/bpf/test_verifier.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -208,6 +208,17 @@ static struct bpf_test tests[] = {
		.errstr = "R0 !read_ok",
		.result = REJECT,
		},
		{
		"program doesn't init R0 before exit in all branches",
		.insns = {
		BPF_JMP_IMM(BPF_JGE, BPF_REG_1, 0, 2),
		BPF_MOV64_IMM(BPF_REG_0, 1),
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 2),
		BPF_EXIT_INSN(),
		},
		.errstr = "R0 !read_ok",
		.result = REJECT,
		},
		{
		"stack out of bounds",
		.insns = {