1 files changed, 23 insertions, 7 deletions

diff --git a/tools/testing/selftests/bpf/test_align.c b/tools/testing/selftests/bpf/test_align.c
index e19b410125eb..ff8bd7e3e50c 100644
--- a/tools/testing/selftests/bpf/test_align.c
+++ b/tools/testing/selftests/bpf/test_align.c
@@ -446,11 +446,9 @@ static struct bpf_align_test tests[] = {
                 .insns = {
                         PREP_PKT_POINTERS,
                         BPF_MOV64_IMM(BPF_REG_0, 0),
-                        /* ptr & const => unknown & const */
-                        BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
-                        BPF_ALU64_IMM(BPF_AND, BPF_REG_5, 0x40),
-                        /* ptr << const => unknown << const */
-                        BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
+                        /* (ptr - ptr) << 2 */
+                        BPF_MOV64_REG(BPF_REG_5, BPF_REG_3),
+                        BPF_ALU64_REG(BPF_SUB, BPF_REG_5, BPF_REG_2),
                         BPF_ALU64_IMM(BPF_LSH, BPF_REG_5, 2),
                         /* We have a (4n) value.  Let's make a packet offset
                          * out of it.  First add 14, to make it a (4n+2)
@@ -473,8 +471,26 @@ static struct bpf_align_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
                 .result = REJECT,
                 .matches = {
-                        {4, "R5_w=pkt(id=0,off=0,r=0,imm=0)"},
-                        /* R5 bitwise operator &= on pointer prohibited */
+                        {4, "R5_w=pkt_end(id=0,off=0,imm=0)"},
+                        /* (ptr - ptr) << 2 == unknown, (4n) */
+                        {6, "R5_w=inv(id=0,smax_value=9223372036854775804,umax_value=18446744073709551612,var_off=(0x0; 0xfffffffffffffffc))"},
+                        /* (4n) + 14 == (4n+2).  We blow our bounds, because
+                         * the add could overflow.
+                         */
+                        {7, "R5=inv(id=0,var_off=(0x2; 0xfffffffffffffffc))"},
+                        /* Checked s>=0 */
+                        {9, "R5=inv(id=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
+                        /* packet pointer + nonnegative (4n+2) */
+                        {11, "R6_w=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
+                        {13, "R4=pkt(id=1,off=4,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
+                        /* NET_IP_ALIGN + (4n+2) == (4n), alignment is fine.
+                         * We checked the bounds, but it might have been able
+                         * to overflow if the packet pointer started in the
+                         * upper half of the address space.
+                         * So we did not get a 'range' on R6, and the access
+                         * attempt will fail.
+                         */
+                        {15, "R6=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
                 }
         },
         {