Range for XOR and OR operators would not be attempted unless src_reg
would resolve to a single value, i.e. a known constant value.
This condition seems excessive, relative to how easy it is to compute a
safe range for these operators.
BPF self-tests were added to validate the new functionality.
Signed-off-by: Cupertino Miranda <cupertino.miranda@xxxxxxxxxx>
---
kernel/bpf/verifier.c | 3 +-
.../selftests/bpf/progs/verifier_bounds.c | 64 +++++++++++++++++++
2 files changed, 66 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 2aad6d90550f..a219f601569a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13764,7 +13764,8 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
}
if (!src_known &&
- opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) {
+ opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND &&
+ opcode != BPF_XOR && opcode != BPF_OR) {
__mark_reg_unknown(env, dst_reg);
return 0;
}
diff --git a/tools/testing/selftests/bpf/progs/verifier_bounds.c b/tools/testing/selftests/bpf/progs/verifier_bounds.c
index 960998f16306..2fcf46341b30 100644
--- a/tools/testing/selftests/bpf/progs/verifier_bounds.c
+++ b/tools/testing/selftests/bpf/progs/verifier_bounds.c
@@ -885,6 +885,70 @@ l1_%=: r0 = 0; \
: __clobber_all);
}
+SEC("socket")
+__description("bounds check for reg32 <= 1, 0 xor (0,1)")
+__success __failure_unpriv
+__msg_unpriv("R0 min value is outside of the allowed memory range")
+__retval(0)
+__naked void t_0_xor_01(void)
+{
+ asm volatile (" \
+ call %[bpf_get_prandom_u32]; \
+ r6 = r0; \
+ r1 = 0; \
+ *(u64*)(r10 - 8) = r1; \
+ r2 = r10; \
+ r2 += -8; \
+ r1 = %[map_hash_8b] ll; \
+ call %[bpf_map_lookup_elem]; \
+ if r0 != 0 goto l0_%=; \
+ exit; \
+l0_%=: w1 = 0; \
+ r6 >>= 63; \
+ w1 ^= w6; \
+ if w1 <= 1 goto l1_%=; \
+ r0 = *(u64*)(r0 + 8); \
+l1_%=: r0 = 0; \
+ exit; \
+" :
+ : __imm(bpf_map_lookup_elem),
+ __imm_addr(map_hash_8b),
+ __imm(bpf_get_prandom_u32)
+ : __clobber_all);
+}
+
+SEC("socket")
+__description("bounds check for reg32 <= 1, 0 or (0,1)")
+__success __failure_unpriv
+__msg_unpriv("R0 min value is outside of the allowed memory range")
+__retval(0)
+__naked void t_0_or_01(void)
+{
+ asm volatile (" \
+ call %[bpf_get_prandom_u32]; \
+ r6 = r0; \
+ r1 = 0; \
+ *(u64*)(r10 - 8) = r1; \
+ r2 = r10; \
+ r2 += -8; \
+ r1 = %[map_hash_8b] ll; \
+ call %[bpf_map_lookup_elem]; \
+ if r0 != 0 goto l0_%=; \
+ exit; \
+l0_%=: w1 = 0; \
+ r6 >>= 63; \
+ w1 |= w6; \
+ if w1 <= 1 goto l1_%=; \
+ r0 = *(u64*)(r0 + 8); \
+l1_%=: r0 = 0; \
+ exit; \
+" :
+ : __imm(bpf_map_lookup_elem),
+ __imm_addr(map_hash_8b),
+ __imm(bpf_get_prandom_u32)
+ : __clobber_all);
+}
+
SEC("socket")
__description("bounds checks after 32-bit truncation. test 1")
__success __failure_unpriv __msg_unpriv("R0 leaks addr")
--
2.30.2
