// SPDX-License-Identifier: GPL-2.0 #include #include #include "bpf_misc.h" /* Check that precision marks propagate through scalar IDs. * Registers r{0,1,2} have the same scalar ID at the moment when r0 is * marked to be precise, this mark is immediately propagated to r{1,2}. */ SEC("socket") __success __log_level(2) __msg("frame0: regs=r0,r1,r2 stack= before 4: (bf) r3 = r10") __msg("frame0: regs=r0,r1,r2 stack= before 3: (bf) r2 = r0") __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns") __flag(BPF_F_TEST_STATE_FREQ) __naked void precision_same_state(void) { asm volatile ( /* r0 = random number up to 0xff */ "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" /* tie r0.id == r1.id == r2.id */ "r1 = r0;" "r2 = r0;" /* force r0 to be precise, this immediately marks r1 and r2 as * precise as well because of shared IDs */ "r3 = r10;" "r3 += r0;" "r0 = 0;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Same as precision_same_state, but mark propagates through state / * parent state boundary. */ SEC("socket") __success __log_level(2) __msg("frame0: last_idx 6 first_idx 5 subseq_idx -1") __msg("frame0: regs=r0,r1,r2 stack= before 5: (bf) r3 = r10") __msg("frame0: parent state regs=r0,r1,r2 stack=:") __msg("frame0: regs=r0,r1,r2 stack= before 4: (05) goto pc+0") __msg("frame0: regs=r0,r1,r2 stack= before 3: (bf) r2 = r0") __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") __msg("frame0: parent state regs=r0 stack=:") __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns") __flag(BPF_F_TEST_STATE_FREQ) __naked void precision_cross_state(void) { asm volatile ( /* r0 = random number up to 0xff */ "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" /* tie r0.id == r1.id == r2.id */ "r1 = r0;" "r2 = r0;" /* force checkpoint */ "goto +0;" /* force r0 to be precise, this immediately marks r1 and r2 as * precise as well because of shared IDs */ "r3 = r10;" "r3 += r0;" "r0 = 0;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Same as precision_same_state, but break one of the * links, note that r1 is absent from regs=... in __msg below. */ SEC("socket") __success __log_level(2) __msg("frame0: regs=r0,r2 stack= before 5: (bf) r3 = r10") __msg("frame0: regs=r0,r2 stack= before 4: (b7) r1 = 0") __msg("frame0: regs=r0,r2 stack= before 3: (bf) r2 = r0") __msg("frame0: regs=r0 stack= before 2: (bf) r1 = r0") __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns") __flag(BPF_F_TEST_STATE_FREQ) __naked void precision_same_state_broken_link(void) { asm volatile ( /* r0 = random number up to 0xff */ "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" /* tie r0.id == r1.id == r2.id */ "r1 = r0;" "r2 = r0;" /* break link for r1, this is the only line that differs * compared to the previous test */ "r1 = 0;" /* force r0 to be precise, this immediately marks r1 and r2 as * precise as well because of shared IDs */ "r3 = r10;" "r3 += r0;" "r0 = 0;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Same as precision_same_state_broken_link, but with state / * parent state boundary. */ SEC("socket") __success __log_level(2) __msg("frame0: regs=r0,r2 stack= before 6: (bf) r3 = r10") __msg("frame0: regs=r0,r2 stack= before 5: (b7) r1 = 0") __msg("frame0: parent state regs=r0,r2 stack=:") __msg("frame0: regs=r0,r1,r2 stack= before 4: (05) goto pc+0") __msg("frame0: regs=r0,r1,r2 stack= before 3: (bf) r2 = r0") __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") __msg("frame0: parent state regs=r0 stack=:") __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns") __flag(BPF_F_TEST_STATE_FREQ) __naked void precision_cross_state_broken_link(void) { asm volatile ( /* r0 = random number up to 0xff */ "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" /* tie r0.id == r1.id == r2.id */ "r1 = r0;" "r2 = r0;" /* force checkpoint, although link between r1 and r{0,2} is * broken by the next statement current precision tracking * algorithm can't react to it and propagates mark for r1 to * the parent state. */ "goto +0;" /* break link for r1, this is the only line that differs * compared to precision_cross_state() */ "r1 = 0;" /* force r0 to be precise, this immediately marks r1 and r2 as * precise as well because of shared IDs */ "r3 = r10;" "r3 += r0;" "r0 = 0;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Check that precision marks propagate through scalar IDs. * Use the same scalar ID in multiple stack frames, check that * precision information is propagated up the call stack. */ SEC("socket") __success __log_level(2) __msg("11: (0f) r2 += r1") /* Current state */ __msg("frame2: last_idx 11 first_idx 10 subseq_idx -1") __msg("frame2: regs=r1 stack= before 10: (bf) r2 = r10") __msg("frame2: parent state regs=r1 stack=") /* frame1.r{6,7} are marked because mark_precise_scalar_ids() * looks for all registers with frame2.r1.id in the current state */ __msg("frame1: parent state regs=r6,r7 stack=") __msg("frame0: parent state regs=r6 stack=") /* Parent state */ __msg("frame2: last_idx 8 first_idx 8 subseq_idx 10") __msg("frame2: regs=r1 stack= before 8: (85) call pc+1") /* frame1.r1 is marked because of backtracking of call instruction */ __msg("frame1: parent state regs=r1,r6,r7 stack=") __msg("frame0: parent state regs=r6 stack=") /* Parent state */ __msg("frame1: last_idx 7 first_idx 6 subseq_idx 8") __msg("frame1: regs=r1,r6,r7 stack= before 7: (bf) r7 = r1") __msg("frame1: regs=r1,r6 stack= before 6: (bf) r6 = r1") __msg("frame1: parent state regs=r1 stack=") __msg("frame0: parent state regs=r6 stack=") /* Parent state */ __msg("frame1: last_idx 4 first_idx 4 subseq_idx 6") __msg("frame1: regs=r1 stack= before 4: (85) call pc+1") __msg("frame0: parent state regs=r1,r6 stack=") /* Parent state */ __msg("frame0: last_idx 3 first_idx 1 subseq_idx 4") __msg("frame0: regs=r0,r1,r6 stack= before 3: (bf) r6 = r0") __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") __flag(BPF_F_TEST_STATE_FREQ) __naked void precision_many_frames(void) { asm volatile ( /* r0 = random number up to 0xff */ "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" /* tie r0.id == r1.id == r6.id */ "r1 = r0;" "r6 = r0;" "call precision_many_frames__foo;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } static __naked __noinline __used void precision_many_frames__foo(void) { asm volatile ( /* conflate one of the register numbers (r6) with outer frame, * to verify that those are tracked independently */ "r6 = r1;" "r7 = r1;" "call precision_many_frames__bar;" "exit" ::: __clobber_all); } static __naked __noinline __used void precision_many_frames__bar(void) { asm volatile ( /* force r1 to be precise, this immediately marks: * - bar frame r1 * - foo frame r{1,6,7} * - main frame r{1,6} */ "r2 = r10;" "r2 += r1;" "r0 = 0;" "exit;" ::: __clobber_all); } /* Check that scalars with the same IDs are marked precise on stack as * well as in registers. */ SEC("socket") __success __log_level(2) /* foo frame */ __msg("frame1: regs=r1 stack=-8,-16 before 9: (bf) r2 = r10") __msg("frame1: regs=r1 stack=-8,-16 before 8: (7b) *(u64 *)(r10 -16) = r1") __msg("frame1: regs=r1 stack=-8 before 7: (7b) *(u64 *)(r10 -8) = r1") __msg("frame1: regs=r1 stack= before 4: (85) call pc+2") /* main frame */ __msg("frame0: regs=r0,r1 stack=-8 before 3: (7b) *(u64 *)(r10 -8) = r1") __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0") __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255") __flag(BPF_F_TEST_STATE_FREQ) __naked void precision_stack(void) { asm volatile ( /* r0 = random number up to 0xff */ "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" /* tie r0.id == r1.id == fp[-8].id */ "r1 = r0;" "*(u64*)(r10 - 8) = r1;" "call precision_stack__foo;" "r0 = 0;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } static __naked __noinline __used void precision_stack__foo(void) { asm volatile ( /* conflate one of the register numbers (r6) with outer frame, * to verify that those are tracked independently */ "*(u64*)(r10 - 8) = r1;" "*(u64*)(r10 - 16) = r1;" /* force r1 to be precise, this immediately marks: * - foo frame r1,fp{-8,-16} * - main frame r1,fp{-8} */ "r2 = r10;" "r2 += r1;" "exit" ::: __clobber_all); } /* Use two separate scalar IDs to check that these are propagated * independently. */ SEC("socket") __success __log_level(2) /* r{6,7} */ __msg("11: (0f) r3 += r7") __msg("frame0: regs=r6,r7 stack= before 10: (bf) r3 = r10") /* ... skip some insns ... */ __msg("frame0: regs=r6,r7 stack= before 3: (bf) r7 = r0") __msg("frame0: regs=r0,r6 stack= before 2: (bf) r6 = r0") /* r{8,9} */ __msg("12: (0f) r3 += r9") __msg("frame0: regs=r8,r9 stack= before 11: (0f) r3 += r7") /* ... skip some insns ... */ __msg("frame0: regs=r8,r9 stack= before 7: (bf) r9 = r0") __msg("frame0: regs=r0,r8 stack= before 6: (bf) r8 = r0") __flag(BPF_F_TEST_STATE_FREQ) __naked void precision_two_ids(void) { asm volatile ( /* r6 = random number up to 0xff * r6.id == r7.id */ "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" "r6 = r0;" "r7 = r0;" /* same, but for r{8,9} */ "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" "r8 = r0;" "r9 = r0;" /* clear r0 id */ "r0 = 0;" /* force checkpoint */ "goto +0;" "r3 = r10;" /* force r7 to be precise, this also marks r6 */ "r3 += r7;" /* force r9 to be precise, this also marks r8 */ "r3 += r9;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Verify that check_ids() is used by regsafe() for scalars. * * r9 = ... some pointer with range X ... * r6 = ... unbound scalar ID=a ... * r7 = ... unbound scalar ID=b ... * if (r6 > r7) goto +1 * r7 = r6 * if (r7 > X) goto exit * r9 += r6 * ... access memory using r9 ... * * The memory access is safe only if r7 is bounded, * which is true for one branch and not true for another. */ SEC("socket") __failure __msg("register with unbounded min value") __flag(BPF_F_TEST_STATE_FREQ) __naked void check_ids_in_regsafe(void) { asm volatile ( /* Bump allocated stack */ "r1 = 0;" "*(u64*)(r10 - 8) = r1;" /* r9 = pointer to stack */ "r9 = r10;" "r9 += -8;" /* r7 = ktime_get_ns() */ "call %[bpf_ktime_get_ns];" "r7 = r0;" /* r6 = ktime_get_ns() */ "call %[bpf_ktime_get_ns];" "r6 = r0;" /* if r6 > r7 is an unpredictable jump */ "if r6 > r7 goto l1_%=;" "r7 = r6;" "l1_%=:" /* if r7 > 4 ...; transfers range to r6 on one execution path * but does not transfer on another */ "if r7 > 4 goto l2_%=;" /* Access memory at r9[r6], r6 is not always bounded */ "r9 += r6;" "r0 = *(u8*)(r9 + 0);" "l2_%=:" "r0 = 0;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Similar to check_ids_in_regsafe. * The l0 could be reached in two states: * * (1) r6{.id=A}, r7{.id=A}, r8{.id=B} * (2) r6{.id=B}, r7{.id=A}, r8{.id=B} * * Where (2) is not safe, as "r7 > 4" check won't propagate range for it. * This example would be considered safe without changes to * mark_chain_precision() to track scalar values with equal IDs. */ SEC("socket") __failure __msg("register with unbounded min value") __flag(BPF_F_TEST_STATE_FREQ) __naked void check_ids_in_regsafe_2(void) { asm volatile ( /* Bump allocated stack */ "r1 = 0;" "*(u64*)(r10 - 8) = r1;" /* r9 = pointer to stack */ "r9 = r10;" "r9 += -8;" /* r8 = ktime_get_ns() */ "call %[bpf_ktime_get_ns];" "r8 = r0;" /* r7 = ktime_get_ns() */ "call %[bpf_ktime_get_ns];" "r7 = r0;" /* r6 = ktime_get_ns() */ "call %[bpf_ktime_get_ns];" "r6 = r0;" /* scratch .id from r0 */ "r0 = 0;" /* if r6 > r7 is an unpredictable jump */ "if r6 > r7 goto l1_%=;" /* tie r6 and r7 .id */ "r6 = r7;" "l0_%=:" /* if r7 > 4 exit(0) */ "if r7 > 4 goto l2_%=;" /* Access memory at r9[r6] */ "r9 += r6;" "r0 = *(u8*)(r9 + 0);" "l2_%=:" "r0 = 0;" "exit;" "l1_%=:" /* tie r6 and r8 .id */ "r6 = r8;" "goto l0_%=;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Check that scalar IDs *are not* generated on register to register * assignments if source register is a constant. * * If such IDs *are* generated the 'l1' below would be reached in * two states: * * (1) r1{.id=A}, r2{.id=A} * (2) r1{.id=C}, r2{.id=C} * * Thus forcing 'if r1 == r2' verification twice. */ SEC("socket") __success __log_level(2) __msg("11: (1d) if r3 == r4 goto pc+0") __msg("frame 0: propagating r3,r4") __msg("11: safe") __msg("processed 15 insns") __flag(BPF_F_TEST_STATE_FREQ) __naked void no_scalar_id_for_const(void) { asm volatile ( "call %[bpf_ktime_get_ns];" /* unpredictable jump */ "if r0 > 7 goto l0_%=;" /* possibly generate same scalar ids for r3 and r4 */ "r1 = 0;" "r1 = r1;" "r3 = r1;" "r4 = r1;" "goto l1_%=;" "l0_%=:" /* possibly generate different scalar ids for r3 and r4 */ "r1 = 0;" "r2 = 0;" "r3 = r1;" "r4 = r2;" "l1_%=:" /* predictable jump, marks r3 and r4 precise */ "if r3 == r4 goto +0;" "r0 = 0;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Same as no_scalar_id_for_const() but for 32-bit values */ SEC("socket") __success __log_level(2) __msg("11: (1e) if w3 == w4 goto pc+0") __msg("frame 0: propagating r3,r4") __msg("11: safe") __msg("processed 15 insns") __flag(BPF_F_TEST_STATE_FREQ) __naked void no_scalar_id_for_const32(void) { asm volatile ( "call %[bpf_ktime_get_ns];" /* unpredictable jump */ "if r0 > 7 goto l0_%=;" /* possibly generate same scalar ids for r3 and r4 */ "w1 = 0;" "w1 = w1;" "w3 = w1;" "w4 = w1;" "goto l1_%=;" "l0_%=:" /* possibly generate different scalar ids for r3 and r4 */ "w1 = 0;" "w2 = 0;" "w3 = w1;" "w4 = w2;" "l1_%=:" /* predictable jump, marks r1 and r2 precise */ "if w3 == w4 goto +0;" "r0 = 0;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Check that unique scalar IDs are ignored when new verifier state is * compared to cached verifier state. For this test: * - cached state has no id on r1 * - new state has a unique id on r1 */ SEC("socket") __success __log_level(2) __msg("6: (25) if r6 > 0x7 goto pc+1") __msg("7: (57) r1 &= 255") __msg("8: (bf) r2 = r10") __msg("from 6 to 8: safe") __msg("processed 12 insns") __flag(BPF_F_TEST_STATE_FREQ) __naked void ignore_unique_scalar_ids_cur(void) { asm volatile ( "call %[bpf_ktime_get_ns];" "r6 = r0;" "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" /* r1.id == r0.id */ "r1 = r0;" /* make r1.id unique */ "r0 = 0;" "if r6 > 7 goto l0_%=;" /* clear r1 id, but keep the range compatible */ "r1 &= 0xff;" "l0_%=:" /* get here in two states: * - first: r1 has no id (cached state) * - second: r1 has a unique id (should be considered equivalent) */ "r2 = r10;" "r2 += r1;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Check that unique scalar IDs are ignored when new verifier state is * compared to cached verifier state. For this test: * - cached state has a unique id on r1 * - new state has no id on r1 */ SEC("socket") __success __log_level(2) __msg("6: (25) if r6 > 0x7 goto pc+1") __msg("7: (05) goto pc+1") __msg("9: (bf) r2 = r10") __msg("9: safe") __msg("processed 13 insns") __flag(BPF_F_TEST_STATE_FREQ) __naked void ignore_unique_scalar_ids_old(void) { asm volatile ( "call %[bpf_ktime_get_ns];" "r6 = r0;" "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" /* r1.id == r0.id */ "r1 = r0;" /* make r1.id unique */ "r0 = 0;" "if r6 > 7 goto l1_%=;" "goto l0_%=;" "l1_%=:" /* clear r1 id, but keep the range compatible */ "r1 &= 0xff;" "l0_%=:" /* get here in two states: * - first: r1 has a unique id (cached state) * - second: r1 has no id (should be considered equivalent) */ "r2 = r10;" "r2 += r1;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } /* Check that two different scalar IDs in a verified state can't be * mapped to the same scalar ID in current state. */ SEC("socket") __success __log_level(2) /* The exit instruction should be reachable from two states, * use two matches and "processed .. insns" to ensure this. */ __msg("13: (95) exit") __msg("13: (95) exit") __msg("processed 18 insns") __flag(BPF_F_TEST_STATE_FREQ) __naked void two_old_ids_one_cur_id(void) { asm volatile ( /* Give unique scalar IDs to r{6,7} */ "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" "r6 = r0;" "call %[bpf_ktime_get_ns];" "r0 &= 0xff;" "r7 = r0;" "r0 = 0;" /* Maybe make r{6,7} IDs identical */ "if r6 > r7 goto l0_%=;" "goto l1_%=;" "l0_%=:" "r6 = r7;" "l1_%=:" /* Mark r{6,7} precise. * Get here in two states: * - first: r6{.id=A}, r7{.id=B} (cached state) * - second: r6{.id=A}, r7{.id=A} * Currently we don't want to consider such states equivalent. * Thus "exit;" would be verified twice. */ "r2 = r10;" "r2 += r6;" "r2 += r7;" "exit;" : : __imm(bpf_ktime_get_ns) : __clobber_all); } char _license[] SEC("license") = "GPL";