From: Maxim Mikityanskiy maxim@isovalent.com
Adjust the check in bpf_get_spilled_reg to take into account spilled registers narrower than 64 bits. That allows find_equal_scalars to properly adjust the range of all spilled registers that have the same ID. Before this change, it was possible for a register and a spilled register to have the same IDs but different ranges if the spill was narrower than 64 bits and a range check was performed on the register.
Signed-off-by: Maxim Mikityanskiy maxim@isovalent.com --- include/linux/bpf_verifier.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index d07d857ca67f..e11baecbde68 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -453,7 +453,7 @@ struct bpf_verifier_state {
#define bpf_get_spilled_reg(slot, frame, mask) \ (((slot < frame->allocated_stack / BPF_REG_SIZE) && \ - ((1 << frame->stack[slot].slot_type[0]) & (mask))) \ + ((1 << frame->stack[slot].slot_type[BPF_REG_SIZE - 1]) & (mask))) \ ? &frame->stack[slot].spilled_ptr : NULL)
/* Iterate over 'frame', setting 'reg' to either NULL or a spilled register. */