This is a note to let you know that I've just added the patch titled bpf, selftests: Update test case for atomic cmpxchg on r0 with pointer to the 5.15-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-update-test-case-for-atomic-cmpxchg-on-r0-with-pointer.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From e523102cb719cbad1673b6aa2a4d5c1fa6f13799 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Date: Mon, 13 Dec 2021 22:25:23 +0000 Subject: bpf, selftests: Update test case for atomic cmpxchg on r0 with pointer From: Daniel Borkmann <daniel@xxxxxxxxxxxxx> commit e523102cb719cbad1673b6aa2a4d5c1fa6f13799 upstream. Fix up unprivileged test case results for 'Dest pointer in r0' verifier tests given they now need to reject R0 containing a pointer value, and add a couple of new related ones with 32bit cmpxchg as well. root@foo:~/bpf/tools/testing/selftests/bpf# ./test_verifier #0/u invalid and of negative number OK #0/p invalid and of negative number OK [...] #1268/p XDP pkt read, pkt_meta' <= pkt_data, bad access 1 OK #1269/p XDP pkt read, pkt_meta' <= pkt_data, bad access 2 OK #1270/p XDP pkt read, pkt_data <= pkt_meta', good access OK #1271/p XDP pkt read, pkt_data <= pkt_meta', bad access 1 OK #1272/p XDP pkt read, pkt_data <= pkt_meta', bad access 2 OK Summary: 1900 PASSED, 0 SKIPPED, 0 FAILED Acked-by: Brendan Jackman <jackmanb@xxxxxxxxxx> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c | 67 +++++++++++++++++- 1 file changed, 65 insertions(+), 2 deletions(-) --- a/tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c +++ b/tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c @@ -71,6 +71,8 @@ BPF_EXIT_INSN(), }, .result = ACCEPT, + .result_unpriv = REJECT, + .errstr_unpriv = "R0 leaks addr into mem", }, { "Can't use cmpxchg on uninit src reg", @@ -119,7 +121,7 @@ }, .result = ACCEPT, .result_unpriv = REJECT, - .errstr_unpriv = "leaking pointer from stack off -8", + .errstr_unpriv = "R0 leaks addr into mem", }, { "Dest pointer in r0 - succeed, check 2", @@ -140,5 +142,66 @@ }, .result = ACCEPT, .result_unpriv = REJECT, - .errstr_unpriv = "R5 leaks addr into mem", + .errstr_unpriv = "R0 leaks addr into mem", +}, +{ + "Dest pointer in r0 - succeed, check 3", + .insns = { + /* r0 = &val */ + BPF_MOV64_REG(BPF_REG_0, BPF_REG_10), + /* val = r0; */ + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8), + /* r5 = &val */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_10), + /* r0 = atomic_cmpxchg(&val, r0, r5); */ + BPF_ATOMIC_OP(BPF_W, BPF_CMPXCHG, BPF_REG_10, BPF_REG_5, -8), + /* exit(0); */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "invalid size of register fill", + .errstr_unpriv = "R0 leaks addr into mem", +}, +{ + "Dest pointer in r0 - succeed, check 4", + .insns = { + /* r0 = &val */ + BPF_MOV32_REG(BPF_REG_0, BPF_REG_10), + /* val = r0; */ + BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -8), + /* r5 = &val */ + BPF_MOV32_REG(BPF_REG_5, BPF_REG_10), + /* r0 = atomic_cmpxchg(&val, r0, r5); */ + BPF_ATOMIC_OP(BPF_W, BPF_CMPXCHG, BPF_REG_10, BPF_REG_5, -8), + /* r1 = *r10 */ + BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, -8), + /* exit(0); */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .result_unpriv = REJECT, + .errstr_unpriv = "R10 partial copy of pointer", +}, +{ + "Dest pointer in r0 - succeed, check 5", + .insns = { + /* r0 = &val */ + BPF_MOV32_REG(BPF_REG_0, BPF_REG_10), + /* val = r0; */ + BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -8), + /* r5 = &val */ + BPF_MOV32_REG(BPF_REG_5, BPF_REG_10), + /* r0 = atomic_cmpxchg(&val, r0, r5); */ + BPF_ATOMIC_OP(BPF_W, BPF_CMPXCHG, BPF_REG_10, BPF_REG_5, -8), + /* r1 = *r0 */ + BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, -8), + /* exit(0); */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result = REJECT, + .errstr = "R0 invalid mem access", + .errstr_unpriv = "R10 partial copy of pointer", }, Patches currently in stable-queue which might be from daniel@xxxxxxxxxxxxx are queue-5.15/bpf-fix-kernel-address-leakage-in-atomic-fetch.patch queue-5.15/bpf-fix-kernel-address-leakage-in-atomic-cmpxchg-s-r0-aux-reg.patch queue-5.15/bpf-selftests-add-test-case-trying-to-taint-map-value-pointer.patch queue-5.15/bpf-selftests-add-test-case-for-atomic-fetch-on-spilled-pointer.patch queue-5.15/bpf-fix-signed-bounds-propagation-after-mov32.patch queue-5.15/bpf-selftests-update-test-case-for-atomic-cmpxchg-on-r0-with-pointer.patch queue-5.15/bpf-make-32-64-bounds-propagation-slightly-more-robust.patch