This is a note to let you know that I've just added the patch titled bpf, selftests: Add test case trying to taint map value pointer to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-selftests-add-test-case-trying-to-taint-map-value-pointer.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From b1a7288dedc6caf9023f2676b4f5ed34cf0d4029 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Date: Wed, 15 Dec 2021 23:48:54 +0000 Subject: bpf, selftests: Add test case trying to taint map value pointer From: Daniel Borkmann <daniel@xxxxxxxxxxxxx> commit b1a7288dedc6caf9023f2676b4f5ed34cf0d4029 upstream. Add a test case which tries to taint map value pointer arithmetic into a unknown scalar with subsequent export through the map. Before fix: # ./test_verifier 1186 #1186/u map access: trying to leak tained dst reg FAIL Unexpected success to load! verification time 24 usec stack depth 8 processed 15 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 1 #1186/p map access: trying to leak tained dst reg FAIL Unexpected success to load! verification time 8 usec stack depth 8 processed 15 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 1 Summary: 0 PASSED, 0 SKIPPED, 2 FAILED After fix: # ./test_verifier 1186 #1186/u map access: trying to leak tained dst reg OK #1186/p map access: trying to leak tained dst reg OK Summary: 2 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Reviewed-by: John Fastabend <john.fastabend@xxxxxxxxx> Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/bpf/verifier/value_ptr_arith.c | 23 +++++++++++++++++ 1 file changed, 23 insertions(+) --- a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c +++ b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c @@ -849,6 +849,29 @@ .errstr_unpriv = "R0 pointer -= pointer prohibited", }, { + "map access: trying to leak tained dst reg", + .insns = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), + BPF_EXIT_INSN(), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_0), + BPF_MOV32_IMM(BPF_REG_1, 0xFFFFFFFF), + BPF_MOV32_REG(BPF_REG_1, BPF_REG_1), + BPF_ALU64_REG(BPF_SUB, BPF_REG_2, BPF_REG_1), + BPF_STX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .fixup_map_array_48b = { 4 }, + .result = REJECT, + .errstr = "math between map_value pointer and 4294967295 is not allowed", +}, +{ "32bit pkt_ptr -= scalar", .insns = { BPF_LDX_MEM(BPF_W, BPF_REG_8, BPF_REG_1, Patches currently in stable-queue which might be from daniel@xxxxxxxxxxxxx are queue-5.10/bpf-selftests-add-test-case-trying-to-taint-map-value-pointer.patch queue-5.10/bpf-fix-signed-bounds-propagation-after-mov32.patch queue-5.10/bpf-make-32-64-bounds-propagation-slightly-more-robust.patch