This implements the core of the series and causes the verifier to fall back to mitigating Spectre v1 using speculation barriers. The approach was presented at LPC'24 [1] and RAID'24 [2].
If we find any forbidden behavior on a speculative path, we insert a nospec (e.g., lfence speculation barrier on x86) before the instruction and stop verifying the path. While verifying a speculative path, we can furthermore stop verification of that path whenever we encounter a nospec instruction.
A minimal example program would look as follows:
A = true B = true if A goto e f() if B goto e unsafe() e: exit
There are the following speculative and non-speculative paths (`cur->speculative` and `speculative` referring to the value of the push_stack() parameters):
- A = true - B = true - if A goto e - A && !cur->speculative && !speculative - exit - !A && !cur->speculative && speculative - f() - if B goto e - B && cur->speculative && !speculative - exit - !B && cur->speculative && speculative - unsafe()
If f() contains any unsafe behavior under Spectre v1 and the unsafe behavior matches `state->speculative && error_recoverable_with_nospec(err)`, do_check() will now add a nospec before f() instead of rejecting the program:
A = true B = true if A goto e nospec f() if B goto e unsafe() e: exit
Alternatively, the algorithm also takes advantage of nospec instructions inserted for other reasons (e.g., Spectre v4). Taking the program above as an example, speculative path exploration can stop before f() if a nospec was inserted there because of Spectre v4 sanitization.
In this example, all instructions after the nospec are dead code (and with the nospec they are also dead code speculatively).
For this, it relies on the fact that speculation barriers generally prevent all later instructions from executing if the speculation was not correct:
* On Intel x86_64, lfence acts as full speculation barrier, not only as a load fence [3]:
An LFENCE instruction or a serializing instruction will ensure that no later instructions execute, even speculatively, until all prior instructions complete locally. [...] Inserting an LFENCE instruction after a bounds check prevents later operations from executing before the bound check completes.
This was experimentally confirmed in [4].
* On AMD x86_64, lfence is dispatch-serializing [5] (requires MSR C001_1029[1] to be set if the MSR is supported, this happens in init_amd()). AMD further specifies "A dispatch serializing instruction forces the processor to retire the serializing instruction and all previous instructions before the next instruction is executed" [8]. As dispatch is not specific to memory loads or branches, lfence therefore also affects all instructions there. Also, if retiring a branch means it's PC change becomes architectural (should be), this means any "wrong" speculation is aborted as required for this series.
* ARM's SB speculation barrier instruction also affects "any instruction that appears later in the program order than the barrier" [6].
* PowerPC's barrier also affects all subsequent instructions [7]:
[...] executing an ori R31,R31,0 instruction ensures that all instructions preceding the ori R31,R31,0 instruction have completed before the ori R31,R31,0 instruction completes, and that no subsequent instructions are initiated, even out-of-order, until after the ori R31,R31,0 instruction completes. The ori R31,R31,0 instruction may complete before storage accesses associated with instructions preceding the ori R31,R31,0 instruction have been performed
Regarding the example, this implies that `if B goto e` will not execute before `if A goto e` completes. Once `if A goto e` completes, the CPU should find that the speculation was wrong and continue with `exit`.
If there is any other path that leads to `if B goto e` (and therefore `unsafe()`) without going through `if A goto e`, then a nospec will still be needed there. However, this patch assumes this other path will be explored separately and therefore be discovered by the verifier even if the exploration discussed here stops at the nospec.
This patch furthermore has the unfortunate consequence that Spectre v1 mitigations now only support architectures which implement BPF_NOSPEC. Before this commit, Spectre v1 mitigations prevented exploits by rejecting the programs on all architectures. Because some JITs do not implement BPF_NOSPEC, this patch therefore may regress unpriv BPF's security to a limited extent:
* The regression is limited to systems vulnerable to Spectre v1, have unprivileged BPF enabled, and do NOT emit insns for BPF_NOSPEC. The latter is not the case for x86 64- and 32-bit, arm64, and powerpc 64-bit and they are therefore not affected by the regression. According to commit a6f6a95f2580 ("LoongArch, bpf: Fix jit to skip speculation barrier opcode"), LoongArch is not vulnerable to Spectre v1 and therefore also not affected by the regression.
* To the best of my knowledge this regression may therefore only affect MIPS. This is deemed acceptable because unpriv BPF is still disabled there by default. As stated in a previous commit, BPF_NOSPEC could be implemented for MIPS based on GCC's speculation_barrier implementation.
* It is unclear which other architectures (besides x86 64- and 32-bit, ARM64, PowerPC 64-bit, LoongArch, and MIPS) supported by the kernel are vulnerable to Spectre v1. Also, it is not clear if barriers are available on these architectures. Implementing BPF_NOSPEC on these architectures therefore is non-trivial. Searching GCC and the kernel for speculation barrier implementations for these architectures yielded no result.
* If any of those regressed systems is also vulnerable to Spectre v4, the system was already vulnerable to Spectre v4 attacks based on unpriv BPF before this patch and the impact is therefore further limited.
As an alternative to regressing security, one could still reject programs if the architecture does not emit BPF_NOSPEC (e.g., by removing the empty BPF_NOSPEC-case from all JITs except for LoongArch where it appears justified). However, this will cause rejections on these archs that are likely unfounded in the vast majority of cases.
In the tests, some are now successful where we previously had a false-positive (i.e., rejection). Change them to reflect where the nospec should be inserted (using __xlated_unpriv) and modify the error message if the nospec is able to mitigate a problem that previously shadowed another problem (in that case __xlated_unpriv does not work, therefore just add a comment).
Define SPEC_V1 to avoid duplicating this ifdef whenever we check for nospec insns using __xlated_unpriv, define it here once. This also improves readability. PowerPC can probably also be added here. However, omit it for now because the BPF CI currently does not include a test.
Limit it to EPERM, EACCES, and EINVAL (and not everything except for EFAULT and ENOMEM) as it already has the desired effect for most real-world programs. Briefly went through all the occurrences of EPERM, EINVAL, and EACCESS in verifier.c to validate that catching them like this makes sense.
Thanks to Dustin for their help in checking the vendor documentation.
[1] https://lpc.events/event/18/contributions/1954/ ("Mitigating Spectre-PHT using Speculation Barriers in Linux eBPF") [2] https://arxiv.org/pdf/2405.00078 ("VeriFence: Lightweight and Precise Spectre Defenses for Untrusted Linux Kernel Extensions") [3] https://www.intel.com/content/www/us/en/developer/articles/technical/softwar... ("Managed Runtime Speculative Execution Side Channel Mitigations") [4] https://dl.acm.org/doi/pdf/10.1145/3359789.3359837 ("Speculator: a tool to analyze speculative execution attacks and mitigations" - Section 4.6 "Stopping Speculative Execution") [5] https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/program... ("White Paper - SOFTWARE TECHNIQUES FOR MANAGING SPECULATION ON AMD PROCESSORS - REVISION 5.09.23") [6] https://developer.arm.com/documentation/ddi0597/2020-12/Base-Instructions/SB... ("SB - Speculation Barrier - Arm Armv8-A A32/T32 Instruction Set Architecture (2020-12)") [7] https://wiki.raptorcs.com/w/images/5/5f/OPF_PowerISA_v3.1C.pdf ("Power ISA™ - Version 3.1C - May 26, 2024 - Section 9.2.1 of Book III") [8] https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/program... ("AMD64 Architecture Programmer’s Manual Volumes 1–5 - Revision 4.08 - April 2024 - 7.6.4 Serializing Instructions")
Signed-off-by: Luis Gerhorst luis.gerhorst@fau.de Acked-by: Kumar Kartikeya Dwivedi memxor@gmail.com Acked-by: Henriette Herzog henriette.herzog@rub.de Cc: Dustin Nguyen nguyen@cs.fau.de Cc: Maximilian Ott ott@cs.fau.de Cc: Milan Stephan milan.stephan@fau.de --- include/linux/bpf_verifier.h | 1 + kernel/bpf/verifier.c | 78 ++++++++++++++++++- tools/testing/selftests/bpf/progs/bpf_misc.h | 4 + .../selftests/bpf/progs/verifier_and.c | 8 +- .../selftests/bpf/progs/verifier_bounds.c | 61 ++++++++++++--- .../selftests/bpf/progs/verifier_movsx.c | 16 +++- .../selftests/bpf/progs/verifier_unpriv.c | 8 +- .../bpf/progs/verifier_value_ptr_arith.c | 16 +++- .../selftests/bpf/verifier/dead_code.c | 3 +- tools/testing/selftests/bpf/verifier/jmp32.c | 33 +++----- tools/testing/selftests/bpf/verifier/jset.c | 10 +-- 11 files changed, 184 insertions(+), 54 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 2b0954202226..e6c26393c029 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -580,6 +580,7 @@ struct bpf_insn_aux_data { u64 map_key_state; /* constant (32 bit) key tracking for maps */ int ctx_field_size; /* the ctx field size for load insn, maybe 0 */ u32 seen; /* this insn was processed by the verifier at env->pass_cnt */ + bool nospec; /* do not execute this instruction speculatively */ bool nospec_result; /* result is unsafe under speculation, nospec must follow */ bool zext_dst; /* this insn zero extends dst reg */ bool needs_zext; /* alu op needs to clear upper bits */ diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index af79f4d7692f..2b887989f521 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2012,6 +2012,18 @@ static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx, return 0; }
+static bool error_recoverable_with_nospec(int err) +{ + /* Should only return true for non-fatal errors that are allowed to + * occur during speculative verification. For these we can insert a + * nospec and the program might still be accepted. Do not include + * something like ENOMEM because it is likely to re-occur for the next + * architectural path once it has been recovered-from in all speculative + * paths. + */ + return err == -EPERM || err == -EACCES || err == -EINVAL; +} + static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx, bool speculative) @@ -11146,7 +11158,7 @@ static int check_get_func_ip(struct bpf_verifier_env *env) return -ENOTSUPP; }
-static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env) +static struct bpf_insn_aux_data *cur_aux(const struct bpf_verifier_env *env) { return &env->insn_aux_data[env->insn_idx]; } @@ -14014,7 +14026,9 @@ static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env, const struct bpf_insn *insn) { - return env->bypass_spec_v1 || BPF_SRC(insn->code) == BPF_K; + return env->bypass_spec_v1 || + BPF_SRC(insn->code) == BPF_K || + cur_aux(env)->nospec; }
static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux, @@ -19723,10 +19737,41 @@ static int do_check(struct bpf_verifier_env *env) sanitize_mark_insn_seen(env); prev_insn_idx = env->insn_idx;
+ /* Reduce verification complexity by stopping speculative path + * verification when a nospec is encountered. + */ + if (state->speculative && cur_aux(env)->nospec) + goto process_bpf_exit; + err = do_check_insn(env, &do_print_state); - if (err < 0) { + if (state->speculative && error_recoverable_with_nospec(err)) { + /* Prevent this speculative path from ever reaching the + * insn that would have been unsafe to execute. + */ + cur_aux(env)->nospec = true; + /* If it was an ADD/SUB insn, potentially remove any + * markings for alu sanitization. + */ + cur_aux(env)->alu_state = 0; + goto process_bpf_exit; + } else if (err < 0) { return err; } else if (err == PROCESS_BPF_EXIT) { + goto process_bpf_exit; + } + WARN_ON_ONCE(err); + + if (state->speculative && cur_aux(env)->nospec_result) { + /* If we are on a path that performed a jump-op, this + * may skip a nospec patched-in after the jump. This can + * currently never happen because nospec_result is only + * used for the write-ops + * `*(size*)(dst_reg+off)=src_reg|imm32` which must + * never skip the following insn. Still, add a warning + * to document this in case nospec_result is used + * elsewhere in the future. + */ + WARN_ON_ONCE(env->insn_idx != prev_insn_idx + 1); process_bpf_exit: mark_verifier_state_scratched(env); update_branch_counts(env, env->cur_state); @@ -19744,7 +19789,6 @@ static int do_check(struct bpf_verifier_env *env) continue; } } - WARN_ON_ONCE(err); }
return 0; @@ -20872,6 +20916,29 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) bpf_convert_ctx_access_t convert_ctx_access; u8 mode;
+ if (env->insn_aux_data[i + delta].nospec) { + WARN_ON_ONCE(env->insn_aux_data[i + delta].alu_state); + struct bpf_insn patch[] = { + BPF_ST_NOSPEC(), + *insn, + }; + + cnt = ARRAY_SIZE(patch); + new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt); + if (!new_prog) + return -ENOMEM; + + delta += cnt - 1; + env->prog = new_prog; + insn = new_prog->insnsi + i + delta; + /* This can not be easily merged with the + * nospec_result-case, because an insn may require a + * nospec before and after itself. Therefore also do not + * 'continue' here but potentially apply further + * patching to insn. *insn should equal patch[1] now. + */ + } + if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) || insn->code == (BPF_LDX | BPF_MEM | BPF_H) || insn->code == (BPF_LDX | BPF_MEM | BPF_W) || @@ -20922,6 +20989,9 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
if (type == BPF_WRITE && env->insn_aux_data[i + delta].nospec_result) { + /* nospec_result is only used to mitigate Spectre v4 and + * to limit verification-time for Spectre v1. + */ struct bpf_insn patch[] = { *insn, BPF_ST_NOSPEC(), diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h b/tools/testing/selftests/bpf/progs/bpf_misc.h index 6e208e24ba3b..a678463e972c 100644 --- a/tools/testing/selftests/bpf/progs/bpf_misc.h +++ b/tools/testing/selftests/bpf/progs/bpf_misc.h @@ -231,4 +231,8 @@ #define CAN_USE_LOAD_ACQ_STORE_REL #endif
+#if defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86) +#define SPEC_V1 +#endif + #endif diff --git a/tools/testing/selftests/bpf/progs/verifier_and.c b/tools/testing/selftests/bpf/progs/verifier_and.c index e97e518516b6..2b4fdca162be 100644 --- a/tools/testing/selftests/bpf/progs/verifier_and.c +++ b/tools/testing/selftests/bpf/progs/verifier_and.c @@ -85,8 +85,14 @@ l0_%=: r0 = r0; \
SEC("socket") __description("check known subreg with unknown reg") -__success __failure_unpriv __msg_unpriv("R1 !read_ok") +__success __success_unpriv __retval(0) +#ifdef SPEC_V1 +__xlated_unpriv("if w0 < 0x1 goto pc+2") +__xlated_unpriv("nospec") /* inserted to prevent `R1 !read_ok'` */ +__xlated_unpriv("goto pc-1") /* `r1 = *(u32*)(r1 + 512)`, sanitized dead code */ +__xlated_unpriv("r0 = 0") +#endif __naked void known_subreg_with_unknown_reg(void) { asm volatile (" \ diff --git a/tools/testing/selftests/bpf/progs/verifier_bounds.c b/tools/testing/selftests/bpf/progs/verifier_bounds.c index 0eb33bb801b5..30e16153fdf1 100644 --- a/tools/testing/selftests/bpf/progs/verifier_bounds.c +++ b/tools/testing/selftests/bpf/progs/verifier_bounds.c @@ -620,8 +620,14 @@ l1_%=: exit; \
SEC("socket") __description("bounds check mixed 32bit and 64bit arithmetic. test1") -__success __failure_unpriv __msg_unpriv("R0 invalid mem access 'scalar'") +__success __success_unpriv __retval(0) +#ifdef SPEC_V1 +__xlated_unpriv("goto pc+2") +__xlated_unpriv("nospec") /* inserted to prevent `R0 invalid mem access 'scalar'` */ +__xlated_unpriv("goto pc-1") /* sanitized dead code */ +__xlated_unpriv("exit") +#endif __naked void _32bit_and_64bit_arithmetic_test1(void) { asm volatile (" \ @@ -643,8 +649,14 @@ l1_%=: exit; \
SEC("socket") __description("bounds check mixed 32bit and 64bit arithmetic. test2") -__success __failure_unpriv __msg_unpriv("R0 invalid mem access 'scalar'") +__success __success_unpriv __retval(0) +#ifdef SPEC_V1 +__xlated_unpriv("goto pc+2") +__xlated_unpriv("nospec") /* inserted to prevent `R0 invalid mem access 'scalar'` */ +__xlated_unpriv("goto pc-1") /* sanitized dead code */ +__xlated_unpriv("exit") +#endif __naked void _32bit_and_64bit_arithmetic_test2(void) { asm volatile (" \ @@ -691,9 +703,14 @@ l0_%=: r0 = 0; \
SEC("socket") __description("bounds check for reg = 0, reg xor 1") -__success __failure_unpriv -__msg_unpriv("R0 min value is outside of the allowed memory range") +__success __success_unpriv __retval(0) +#ifdef SPEC_V1 +__xlated_unpriv("if r1 != 0x0 goto pc+2") +__xlated_unpriv("nospec") /* inserted to prevent `R0 min value is outside of the allowed memory range` */ +__xlated_unpriv("goto pc-1") /* sanitized dead code */ +__xlated_unpriv("r0 = 0") +#endif __naked void reg_0_reg_xor_1(void) { asm volatile (" \ @@ -719,9 +736,14 @@ l1_%=: r0 = 0; \
SEC("socket") __description("bounds check for reg32 = 0, reg32 xor 1") -__success __failure_unpriv -__msg_unpriv("R0 min value is outside of the allowed memory range") +__success __success_unpriv __retval(0) +#ifdef SPEC_V1 +__xlated_unpriv("if w1 != 0x0 goto pc+2") +__xlated_unpriv("nospec") /* inserted to prevent `R0 min value is outside of the allowed memory range` */ +__xlated_unpriv("goto pc-1") /* sanitized dead code */ +__xlated_unpriv("r0 = 0") +#endif __naked void reg32_0_reg32_xor_1(void) { asm volatile (" \ @@ -747,9 +769,14 @@ l1_%=: r0 = 0; \
SEC("socket") __description("bounds check for reg = 2, reg xor 3") -__success __failure_unpriv -__msg_unpriv("R0 min value is outside of the allowed memory range") +__success __success_unpriv __retval(0) +#ifdef SPEC_V1 +__xlated_unpriv("if r1 > 0x0 goto pc+2") +__xlated_unpriv("nospec") /* inserted to prevent `R0 min value is outside of the allowed memory range` */ +__xlated_unpriv("goto pc-1") /* sanitized dead code */ +__xlated_unpriv("r0 = 0") +#endif __naked void reg_2_reg_xor_3(void) { asm volatile (" \ @@ -829,9 +856,14 @@ l1_%=: r0 = 0; \
SEC("socket") __description("bounds check for reg > 0, reg xor 3") -__success __failure_unpriv -__msg_unpriv("R0 min value is outside of the allowed memory range") +__success __success_unpriv __retval(0) +#ifdef SPEC_V1 +__xlated_unpriv("if r1 >= 0x0 goto pc+2") +__xlated_unpriv("nospec") /* inserted to prevent `R0 min value is outside of the allowed memory range` */ +__xlated_unpriv("goto pc-1") /* sanitized dead code */ +__xlated_unpriv("r0 = 0") +#endif __naked void reg_0_reg_xor_3(void) { asm volatile (" \ @@ -858,9 +890,14 @@ l1_%=: r0 = 0; \
SEC("socket") __description("bounds check for reg32 > 0, reg32 xor 3") -__success __failure_unpriv -__msg_unpriv("R0 min value is outside of the allowed memory range") +__success __success_unpriv __retval(0) +#ifdef SPEC_V1 +__xlated_unpriv("if w1 >= 0x0 goto pc+2") +__xlated_unpriv("nospec") /* inserted to prevent `R0 min value is outside of the allowed memory range` */ +__xlated_unpriv("goto pc-1") /* sanitized dead code */ +__xlated_unpriv("r0 = 0") +#endif __naked void reg32_0_reg32_xor_3(void) { asm volatile (" \ diff --git a/tools/testing/selftests/bpf/progs/verifier_movsx.c b/tools/testing/selftests/bpf/progs/verifier_movsx.c index 994bbc346d25..a4d8814eb5ed 100644 --- a/tools/testing/selftests/bpf/progs/verifier_movsx.c +++ b/tools/testing/selftests/bpf/progs/verifier_movsx.c @@ -245,7 +245,13 @@ l0_%=: \ SEC("socket") __description("MOV32SX, S8, var_off not u32_max, positive after s8 extension") __success __retval(0) -__failure_unpriv __msg_unpriv("frame pointer is read only") +__success_unpriv +#ifdef SPEC_V1 +__xlated_unpriv("w0 = 0") +__xlated_unpriv("exit") +__xlated_unpriv("nospec") /* inserted to prevent `frame pointer is read only` */ +__xlated_unpriv("goto pc-1") +#endif __naked void mov64sx_s32_varoff_2(void) { asm volatile (" \ @@ -267,7 +273,13 @@ l0_%=: \ SEC("socket") __description("MOV32SX, S8, var_off not u32_max, negative after s8 extension") __success __retval(0) -__failure_unpriv __msg_unpriv("frame pointer is read only") +__success_unpriv +#ifdef SPEC_V1 +__xlated_unpriv("w0 = 0") +__xlated_unpriv("exit") +__xlated_unpriv("nospec") /* inserted to prevent `frame pointer is read only` */ +__xlated_unpriv("goto pc-1") +#endif __naked void mov64sx_s32_varoff_3(void) { asm volatile (" \ diff --git a/tools/testing/selftests/bpf/progs/verifier_unpriv.c b/tools/testing/selftests/bpf/progs/verifier_unpriv.c index a4a5e2071604..c42c3839b30c 100644 --- a/tools/testing/selftests/bpf/progs/verifier_unpriv.c +++ b/tools/testing/selftests/bpf/progs/verifier_unpriv.c @@ -572,8 +572,14 @@ l0_%=: exit; \
SEC("socket") __description("alu32: mov u32 const") -__success __failure_unpriv __msg_unpriv("R7 invalid mem access 'scalar'") +__success __success_unpriv __retval(0) +#ifdef SPEC_V1 +__xlated_unpriv("if r0 == 0x0 goto pc+2") +__xlated_unpriv("nospec") /* inserted to prevent `R7 invalid mem access 'scalar'` */ +__xlated_unpriv("goto pc-1") /* sanitized dead code */ +__xlated_unpriv("exit") +#endif __naked void alu32_mov_u32_const(void) { asm volatile (" \ diff --git a/tools/testing/selftests/bpf/progs/verifier_value_ptr_arith.c b/tools/testing/selftests/bpf/progs/verifier_value_ptr_arith.c index 5ba6e53571c8..fcea9819e359 100644 --- a/tools/testing/selftests/bpf/progs/verifier_value_ptr_arith.c +++ b/tools/testing/selftests/bpf/progs/verifier_value_ptr_arith.c @@ -398,7 +398,8 @@ l2_%=: r0 = 1; \
SEC("socket") __description("map access: mixing value pointer and scalar, 1") -__success __failure_unpriv __msg_unpriv("R2 pointer comparison prohibited") +__success __failure_unpriv +__msg_unpriv("R2 tried to add from different maps, paths or scalars, pointer arithmetic with it prohibited for !root") __retval(0) __naked void value_pointer_and_scalar_1(void) { @@ -433,6 +434,7 @@ l2_%=: /* common instruction */ \ l3_%=: /* branch B */ \ r0 = 0x13371337; \ /* verifier follows fall-through */ \ + /* unpriv: nospec (inserted to prevent `R2 pointer comparison prohibited`) */\ if r2 != 0x100000 goto l4_%=; \ r0 = 0; \ exit; \ @@ -450,7 +452,8 @@ l4_%=: /* fake-dead code; targeted from branch A to \
SEC("socket") __description("map access: mixing value pointer and scalar, 2") -__success __failure_unpriv __msg_unpriv("R0 invalid mem access 'scalar'") +__success __failure_unpriv +__msg_unpriv("R2 tried to add from different maps, paths or scalars, pointer arithmetic with it prohibited for !root") __retval(0) __naked void value_pointer_and_scalar_2(void) { @@ -492,6 +495,7 @@ l4_%=: /* fake-dead code; targeted from branch A to \ * prevent dead code sanitization, rejected \ * via branch B however \ */ \ + /* unpriv: nospec (inserted to prevent `R0 invalid mem access 'scalar'`) */\ r0 = *(u8*)(r0 + 0); \ r0 = 0; \ exit; \ @@ -1296,9 +1300,13 @@ l0_%=: r0 = 1; \
SEC("socket") __description("map access: value_ptr -= unknown scalar, 2") -__success __failure_unpriv -__msg_unpriv("R0 pointer arithmetic of map value goes out of range") +__success __success_unpriv __retval(1) +#ifdef SPEC_V1 +__xlated_unpriv("r1 &= 7") +__xlated_unpriv("nospec") /* inserted to prevent `R0 pointer arithmetic of map value goes out of range` */ +__xlated_unpriv("r0 -= r1") +#endif __naked void value_ptr_unknown_scalar_2_2(void) { asm volatile (" \ diff --git a/tools/testing/selftests/bpf/verifier/dead_code.c b/tools/testing/selftests/bpf/verifier/dead_code.c index ee454327e5c6..77207b498c6f 100644 --- a/tools/testing/selftests/bpf/verifier/dead_code.c +++ b/tools/testing/selftests/bpf/verifier/dead_code.c @@ -2,14 +2,13 @@ "dead code: start", .insns = { BPF_JMP_IMM(BPF_JA, 0, 0, 2), + /* unpriv: nospec (inserted to prevent "R9 !read_ok") */ BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0), BPF_JMP_IMM(BPF_JA, 0, 0, 2), BPF_MOV64_IMM(BPF_REG_0, 7), BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 10, -4), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R9 !read_ok", - .result_unpriv = REJECT, .result = ACCEPT, .retval = 7, }, diff --git a/tools/testing/selftests/bpf/verifier/jmp32.c b/tools/testing/selftests/bpf/verifier/jmp32.c index 43776f6f92f4..91d83e9cb148 100644 --- a/tools/testing/selftests/bpf/verifier/jmp32.c +++ b/tools/testing/selftests/bpf/verifier/jmp32.c @@ -84,11 +84,10 @@ BPF_JMP32_IMM(BPF_JSET, BPF_REG_7, 0x10, 1), BPF_EXIT_INSN(), BPF_JMP32_IMM(BPF_JGE, BPF_REG_7, 0x10, 1), + /* unpriv: nospec (inserted to prevent "R9 !read_ok") */ BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R9 !read_ok", - .result_unpriv = REJECT, .result = ACCEPT, }, { @@ -149,11 +148,10 @@ BPF_JMP32_IMM(BPF_JEQ, BPF_REG_7, 0x10, 1), BPF_EXIT_INSN(), BPF_JMP32_IMM(BPF_JSGE, BPF_REG_7, 0xf, 1), + /* unpriv: nospec (inserted to prevent "R9 !read_ok") */ BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R9 !read_ok", - .result_unpriv = REJECT, .result = ACCEPT, }, { @@ -214,11 +212,10 @@ BPF_JMP32_IMM(BPF_JNE, BPF_REG_7, 0x10, 1), BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x10, 1), BPF_EXIT_INSN(), + /* unpriv: nospec (inserted to prevent "R9 !read_ok") */ BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R9 !read_ok", - .result_unpriv = REJECT, .result = ACCEPT, }, { @@ -283,11 +280,10 @@ BPF_JMP32_REG(BPF_JGE, BPF_REG_7, BPF_REG_8, 1), BPF_EXIT_INSN(), BPF_JMP32_IMM(BPF_JGE, BPF_REG_7, 0x7ffffff0, 1), + /* unpriv: nospec (inserted to prevent "R0 invalid mem access 'scalar'") */ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R0 invalid mem access 'scalar'", - .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, @@ -354,11 +350,10 @@ BPF_JMP32_REG(BPF_JGT, BPF_REG_7, BPF_REG_8, 1), BPF_EXIT_INSN(), BPF_JMP_IMM(BPF_JGT, BPF_REG_7, 0x7ffffff0, 1), + /* unpriv: nospec (inserted to prevent "R0 invalid mem access 'scalar'") */ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R0 invalid mem access 'scalar'", - .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, @@ -425,11 +420,10 @@ BPF_JMP32_REG(BPF_JLE, BPF_REG_7, BPF_REG_8, 1), BPF_EXIT_INSN(), BPF_JMP32_IMM(BPF_JLE, BPF_REG_7, 0x7ffffff0, 1), + /* unpriv: nospec (inserted to prevent "R0 invalid mem access 'scalar'") */ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R0 invalid mem access 'scalar'", - .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, @@ -496,11 +490,10 @@ BPF_JMP32_REG(BPF_JLT, BPF_REG_7, BPF_REG_8, 1), BPF_EXIT_INSN(), BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0x7ffffff0, 1), + /* unpriv: nospec (inserted to prevent "R0 invalid mem access 'scalar'") */ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R0 invalid mem access 'scalar'", - .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, @@ -567,11 +560,10 @@ BPF_JMP32_REG(BPF_JSGE, BPF_REG_7, BPF_REG_8, 1), BPF_EXIT_INSN(), BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0x7ffffff0, 1), + /* unpriv: nospec (inserted to prevent "R0 invalid mem access 'scalar'") */ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R0 invalid mem access 'scalar'", - .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, @@ -638,11 +630,10 @@ BPF_JMP32_REG(BPF_JSGT, BPF_REG_7, BPF_REG_8, 1), BPF_EXIT_INSN(), BPF_JMP_IMM(BPF_JSGT, BPF_REG_7, -2, 1), + /* unpriv: nospec (inserted to prevent "R0 invalid mem access 'scalar'") */ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R0 invalid mem access 'scalar'", - .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, @@ -709,11 +700,10 @@ BPF_JMP32_REG(BPF_JSLE, BPF_REG_7, BPF_REG_8, 1), BPF_EXIT_INSN(), BPF_JMP_IMM(BPF_JSLE, BPF_REG_7, 0x7ffffff0, 1), + /* unpriv: nospec (inserted to prevent "R0 invalid mem access 'scalar'") */ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R0 invalid mem access 'scalar'", - .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, @@ -780,11 +770,10 @@ BPF_JMP32_REG(BPF_JSLT, BPF_REG_7, BPF_REG_8, 1), BPF_EXIT_INSN(), BPF_JMP32_IMM(BPF_JSLT, BPF_REG_7, -1, 1), + /* unpriv: nospec (inserted to prevent "R0 invalid mem access 'scalar'") */ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0), BPF_EXIT_INSN(), }, - .errstr_unpriv = "R0 invalid mem access 'scalar'", - .result_unpriv = REJECT, .result = ACCEPT, .retval = 2, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, diff --git a/tools/testing/selftests/bpf/verifier/jset.c b/tools/testing/selftests/bpf/verifier/jset.c index 11fc68da735e..e901eefd774a 100644 --- a/tools/testing/selftests/bpf/verifier/jset.c +++ b/tools/testing/selftests/bpf/verifier/jset.c @@ -78,12 +78,11 @@ .insns = { BPF_MOV64_IMM(BPF_REG_0, 1), BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 1, 1), + /* unpriv: nospec (inserted to prevent "R9 !read_ok") */ BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0), BPF_EXIT_INSN(), }, .prog_type = BPF_PROG_TYPE_SOCKET_FILTER, - .errstr_unpriv = "R9 !read_ok", - .result_unpriv = REJECT, .retval = 1, .result = ACCEPT, }, @@ -136,13 +135,12 @@ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32), BPF_ALU64_IMM(BPF_OR, BPF_REG_0, 2), BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 3, 1), + /* unpriv: nospec (inserted to prevent "R9 !read_ok") */ BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0), BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }, .prog_type = BPF_PROG_TYPE_SOCKET_FILTER, - .errstr_unpriv = "R9 !read_ok", - .result_unpriv = REJECT, .result = ACCEPT, }, { @@ -154,16 +152,16 @@ BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0xff), BPF_JMP_IMM(BPF_JSET, BPF_REG_1, 0xf0, 3), BPF_JMP_IMM(BPF_JLT, BPF_REG_1, 0x10, 1), + /* unpriv: nospec (inserted to prevent "R9 !read_ok") */ BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0), BPF_EXIT_INSN(), BPF_JMP_IMM(BPF_JSET, BPF_REG_1, 0x10, 1), BPF_EXIT_INSN(), BPF_JMP_IMM(BPF_JGE, BPF_REG_1, 0x10, 1), + /* unpriv: nospec (inserted to prevent "R9 !read_ok") */ BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0), BPF_EXIT_INSN(), }, .prog_type = BPF_PROG_TYPE_SOCKET_FILTER, - .errstr_unpriv = "R9 !read_ok", - .result_unpriv = REJECT, .result = ACCEPT, },