From 56145d237385ca0e7ca9ff7b226aaf2eb8ef368b Mon Sep 17 00:00:00 2001 From: Lang Xu Date: Tue, 3 Mar 2026 17:52:17 +0800 Subject: bpf: Fix a UAF issue in bpf_trampoline_link_cgroup_shim The root cause of this bug is that when 'bpf_link_put' reduces the refcount of 'shim_link->link.link' to zero, the resource is considered released but may still be referenced via 'tr->progs_hlist' in 'cgroup_shim_find'. The actual cleanup of 'tr->progs_hlist' in 'bpf_shim_tramp_link_release' is deferred. During this window, another process can cause a use-after-free via 'bpf_trampoline_link_cgroup_shim'. Based on Martin KaFai Lau's suggestions, I have created a simple patch. To fix this: Add an atomic non-zero check in 'bpf_trampoline_link_cgroup_shim'. Only increment the refcount if it is not already zero. Testing: I verified the fix by adding a delay in 'bpf_shim_tramp_link_release' to make the bug easier to trigger: static void bpf_shim_tramp_link_release(struct bpf_link *link) { /* ... */ if (!shim_link->trampoline) return; + msleep(100); WARN_ON_ONCE(bpf_trampoline_unlink_prog(&shim_link->link, shim_link->trampoline, NULL)); bpf_trampoline_put(shim_link->trampoline); } Before the patch, running a PoC easily reproduced the crash(almost 100%) with a call trace similar to KaiyanM's report. After the patch, the bug no longer occurs even after millions of iterations. Fixes: 69fd337a975c ("bpf: per-cgroup lsm flavor") Reported-by: Kaiyan Mei Closes: https://lore.kernel.org/bpf/3c4ebb0b.46ff8.19abab8abe2.Coremail.kaiyanm@hust.edu.cn/ Signed-off-by: Lang Xu Signed-off-by: Martin KaFai Lau Link: https://patch.msgid.link/279EEE1BA1DDB49D+20260303095217.34436-1-xulang@uniontech.com --- kernel/bpf/trampoline.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 84db9e658e52..f02254a21585 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -1002,10 +1002,8 @@ int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog, mutex_lock(&tr->mutex); shim_link = cgroup_shim_find(tr, bpf_func); - if (shim_link) { + if (shim_link && !IS_ERR(bpf_link_inc_not_zero(&shim_link->link.link))) { /* Reusing existing shim attached by the other program. */ - bpf_link_inc(&shim_link->link.link); - mutex_unlock(&tr->mutex); bpf_trampoline_put(tr); /* bpf_trampoline_get above */ return 0; -- cgit v1.2.3 From 7fe44c4388146bdbb3c5932d81a26d9fa0fd3ec9 Mon Sep 17 00:00:00 2001 From: Christian Loehle Date: Fri, 6 Mar 2026 10:49:18 +0000 Subject: bpf: drop kthread_exit from noreturn_deny kthread_exit became a macro to do_exit in commit 28aaa9c39945 ("kthread: consolidate kthread exit paths to prevent use-after-free"), so there is no kthread_exit function BTF ID to resolve. Remove it from noreturn_deny to avoid resolve_btfids unresolved symbol warnings. Signed-off-by: Christian Loehle Signed-off-by: Linus Torvalds --- kernel/bpf/verifier.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 401d6c4960ec..8db79e593156 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -25261,7 +25261,6 @@ BTF_ID(func, __x64_sys_exit_group) BTF_ID(func, do_exit) BTF_ID(func, do_group_exit) BTF_ID(func, kthread_complete_and_exit) -BTF_ID(func, kthread_exit) BTF_ID(func, make_task_dead) BTF_SET_END(noreturn_deny) -- cgit v1.2.3 From fbc7aef517d8765e4c425d2792409bb9bf2e1f13 Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 6 Mar 2026 16:54:24 -0800 Subject: bpf: Fix u32/s32 bounds when ranges cross min/max boundary MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Same as in __reg64_deduce_bounds(), refine s32/u32 ranges in __reg32_deduce_bounds() in the following situations: - s32 range crosses U32_MAX/0 boundary, positive part of the s32 range overlaps with u32 range: 0 U32_MAX | [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx] | |----------------------------|----------------------------| |xxxxx s32 range xxxxxxxxx] [xxxxxxx| 0 S32_MAX S32_MIN -1 - s32 range crosses U32_MAX/0 boundary, negative part of the s32 range overlaps with u32 range: 0 U32_MAX | [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx] | |----------------------------|----------------------------| |xxxxxxxxx] [xxxxxxxxxxxx s32 range | 0 S32_MAX S32_MIN -1 - No refinement if ranges overlap in two intervals. This helps for e.g. consider the following program: call %[bpf_get_prandom_u32]; w0 &= 0xffffffff; if w0 < 0x3 goto 1f; // on fall-through u32 range [3..U32_MAX] if w0 s> 0x1 goto 1f; // on fall-through s32 range [S32_MIN..1] if w0 s< 0x0 goto 1f; // range can be narrowed to [S32_MIN..-1] r10 = 0; 1: ...; The reg_bounds.c selftest is updated to incorporate identical logic, refinement based on non-overflowing range halves: ((x ∩ [0, smax]) ∩ (y ∩ [0, smax])) ∪ ((x ∩ [smin,-1]) ∩ (y ∩ [smin,-1])) Reported-by: Andrea Righi Reported-by: Emil Tsalapatis Closes: https://lore.kernel.org/bpf/aakqucg4vcujVwif@gpd4/T/ Reviewed-by: Emil Tsalapatis Acked-by: Shung-Hsi Yu Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20260306-bpf-32-bit-range-overflow-v3-1-f7f67e060a6b@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 24 +++++++++ .../testing/selftests/bpf/prog_tests/reg_bounds.c | 62 ++++++++++++++++++++-- 2 files changed, 82 insertions(+), 4 deletions(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 401d6c4960ec..f960b382fdb3 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2511,6 +2511,30 @@ static void __reg32_deduce_bounds(struct bpf_reg_state *reg) if ((u32)reg->s32_min_value <= (u32)reg->s32_max_value) { reg->u32_min_value = max_t(u32, reg->s32_min_value, reg->u32_min_value); reg->u32_max_value = min_t(u32, reg->s32_max_value, reg->u32_max_value); + } else { + if (reg->u32_max_value < (u32)reg->s32_min_value) { + /* See __reg64_deduce_bounds() for detailed explanation. + * Refine ranges in the following situation: + * + * 0 U32_MAX + * | [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx] | + * |----------------------------|----------------------------| + * |xxxxx s32 range xxxxxxxxx] [xxxxxxx| + * 0 S32_MAX S32_MIN -1 + */ + reg->s32_min_value = (s32)reg->u32_min_value; + reg->u32_max_value = min_t(u32, reg->u32_max_value, reg->s32_max_value); + } else if ((u32)reg->s32_max_value < reg->u32_min_value) { + /* + * 0 U32_MAX + * | [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx] | + * |----------------------------|----------------------------| + * |xxxxxxxxx] [xxxxxxxxxxxx s32 range | + * 0 S32_MAX S32_MIN -1 + */ + reg->s32_max_value = (s32)reg->u32_max_value; + reg->u32_min_value = max_t(u32, reg->u32_min_value, reg->s32_min_value); + } } } diff --git a/tools/testing/selftests/bpf/prog_tests/reg_bounds.c b/tools/testing/selftests/bpf/prog_tests/reg_bounds.c index 0322f817d07b..04938d0d431b 100644 --- a/tools/testing/selftests/bpf/prog_tests/reg_bounds.c +++ b/tools/testing/selftests/bpf/prog_tests/reg_bounds.c @@ -422,15 +422,69 @@ static bool is_valid_range(enum num_t t, struct range x) } } -static struct range range_improve(enum num_t t, struct range old, struct range new) +static struct range range_intersection(enum num_t t, struct range old, struct range new) { return range(t, max_t(t, old.a, new.a), min_t(t, old.b, new.b)); } +/* + * Result is precise when 'x' and 'y' overlap or form a continuous range, + * result is an over-approximation if 'x' and 'y' do not overlap. + */ +static struct range range_union(enum num_t t, struct range x, struct range y) +{ + if (!is_valid_range(t, x)) + return y; + if (!is_valid_range(t, y)) + return x; + return range(t, min_t(t, x.a, y.a), max_t(t, x.b, y.b)); +} + +/* + * This function attempts to improve x range intersecting it with y. + * range_cast(... to_t ...) looses precision for ranges that pass to_t + * min/max boundaries. To avoid such precision loses this function + * splits both x and y into halves corresponding to non-overflowing + * sub-ranges: [0, smin] and [smax, -1]. + * Final result is computed as follows: + * + * ((x ∩ [0, smax]) ∩ (y ∩ [0, smax])) ∪ + * ((x ∩ [smin,-1]) ∩ (y ∩ [smin,-1])) + * + * Precision might still be lost if final union is not a continuous range. + */ +static struct range range_refine_in_halves(enum num_t x_t, struct range x, + enum num_t y_t, struct range y) +{ + struct range x_pos, x_neg, y_pos, y_neg, r_pos, r_neg; + u64 smax, smin, neg_one; + + if (t_is_32(x_t)) { + smax = (u64)(u32)S32_MAX; + smin = (u64)(u32)S32_MIN; + neg_one = (u64)(u32)(s32)(-1); + } else { + smax = (u64)S64_MAX; + smin = (u64)S64_MIN; + neg_one = U64_MAX; + } + x_pos = range_intersection(x_t, x, range(x_t, 0, smax)); + x_neg = range_intersection(x_t, x, range(x_t, smin, neg_one)); + y_pos = range_intersection(y_t, y, range(x_t, 0, smax)); + y_neg = range_intersection(y_t, y, range(y_t, smin, neg_one)); + r_pos = range_intersection(x_t, x_pos, range_cast(y_t, x_t, y_pos)); + r_neg = range_intersection(x_t, x_neg, range_cast(y_t, x_t, y_neg)); + return range_union(x_t, r_pos, r_neg); + +} + static struct range range_refine(enum num_t x_t, struct range x, enum num_t y_t, struct range y) { struct range y_cast; + if (t_is_32(x_t) == t_is_32(y_t)) + x = range_refine_in_halves(x_t, x, y_t, y); + y_cast = range_cast(y_t, x_t, y); /* If we know that @@ -444,7 +498,7 @@ static struct range range_refine(enum num_t x_t, struct range x, enum num_t y_t, */ if (x_t == S64 && y_t == S32 && y_cast.a <= S32_MAX && y_cast.b <= S32_MAX && (s64)x.a >= S32_MIN && (s64)x.b <= S32_MAX) - return range_improve(x_t, x, y_cast); + return range_intersection(x_t, x, y_cast); /* the case when new range knowledge, *y*, is a 32-bit subregister * range, while previous range knowledge, *x*, is a full register @@ -462,7 +516,7 @@ static struct range range_refine(enum num_t x_t, struct range x, enum num_t y_t, x_swap = range(x_t, swap_low32(x.a, y_cast.a), swap_low32(x.b, y_cast.b)); if (!is_valid_range(x_t, x_swap)) return x; - return range_improve(x_t, x, x_swap); + return range_intersection(x_t, x, x_swap); } if (!t_is_32(x_t) && !t_is_32(y_t) && x_t != y_t) { @@ -480,7 +534,7 @@ static struct range range_refine(enum num_t x_t, struct range x, enum num_t y_t, } /* otherwise, plain range cast and intersection works */ - return range_improve(x_t, x, y_cast); + return range_intersection(x_t, x, y_cast); } /* ======================= -- cgit v1.2.3 From 2658a1720a1944fbaeda937000ad2b3c3dfaf1bb Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 6 Mar 2026 16:02:47 -0800 Subject: bpf: collect only live registers in linked regs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix an inconsistency between func_states_equal() and collect_linked_regs(): - regsafe() uses check_ids() to verify that cached and current states have identical register id mapping. - func_states_equal() calls regsafe() only for registers computed as live by compute_live_registers(). - clean_live_states() is supposed to remove dead registers from cached states, but it can skip states belonging to an iterator-based loop. - collect_linked_regs() collects all registers sharing the same id, ignoring the marks computed by compute_live_registers(). Linked registers are stored in the state's jump history. - backtrack_insn() marks all linked registers for an instruction as precise whenever one of the linked registers is precise. The above might lead to a scenario: - There is an instruction I with register rY known to be dead at I. - Instruction I is reached via two paths: first A, then B. - On path A: - There is an id link between registers rX and rY. - Checkpoint C is created at I. - Linked register set {rX, rY} is saved to the jump history. - rX is marked as precise at I, causing both rX and rY to be marked precise at C. - On path B: - There is no id link between registers rX and rY, otherwise register states are sub-states of those in C. - Because rY is dead at I, check_ids() returns true. - Current state is considered equal to checkpoint C, propagate_precision() propagates spurious precision mark for register rY along the path B. - Depending on a program, this might hit verifier_bug() in the backtrack_insn(), e.g. if rY ∈ [r1..r5] and backtrack_insn() spots a function call. The reproducer program is in the next patch. This was hit by sched_ext scx_lavd scheduler code. Changes in tests: - verifier_scalar_ids.c selftests need modification to preserve some registers as live for __msg() checks. - exceptions_assert.c adjusted to match changes in the verifier log, R0 is dead after conditional instruction and thus does not get range. - precise.c adjusted to match changes in the verifier log, register r9 is dead after comparison and it's range is not important for test. Reported-by: Emil Tsalapatis Fixes: 0fb3cf6110a5 ("bpf: use register liveness information for func_states_equal") Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20260306-linked-regs-and-propagate-precision-v1-1-18e859be570d@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 13 +++-- .../selftests/bpf/progs/exceptions_assert.c | 34 ++++++------- .../selftests/bpf/progs/verifier_scalar_ids.c | 56 ++++++++++++++++------ tools/testing/selftests/bpf/verifier/precise.c | 8 ++-- 4 files changed, 73 insertions(+), 38 deletions(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f960b382fdb3..836ceb128d19 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -17359,17 +17359,24 @@ static void __collect_linked_regs(struct linked_regs *reg_set, struct bpf_reg_st * in verifier state, save R in linked_regs if R->id == id. * If there are too many Rs sharing same id, reset id for leftover Rs. */ -static void collect_linked_regs(struct bpf_verifier_state *vstate, u32 id, +static void collect_linked_regs(struct bpf_verifier_env *env, + struct bpf_verifier_state *vstate, + u32 id, struct linked_regs *linked_regs) { + struct bpf_insn_aux_data *aux = env->insn_aux_data; struct bpf_func_state *func; struct bpf_reg_state *reg; + u16 live_regs; int i, j; id = id & ~BPF_ADD_CONST; for (i = vstate->curframe; i >= 0; i--) { + live_regs = aux[frame_insn_idx(vstate, i)].live_regs_before; func = vstate->frame[i]; for (j = 0; j < BPF_REG_FP; j++) { + if (!(live_regs & BIT(j))) + continue; reg = &func->regs[j]; __collect_linked_regs(linked_regs, reg, id, i, j, true); } @@ -17584,9 +17591,9 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, * if parent state is created. */ if (BPF_SRC(insn->code) == BPF_X && src_reg->type == SCALAR_VALUE && src_reg->id) - collect_linked_regs(this_branch, src_reg->id, &linked_regs); + collect_linked_regs(env, this_branch, src_reg->id, &linked_regs); if (dst_reg->type == SCALAR_VALUE && dst_reg->id) - collect_linked_regs(this_branch, dst_reg->id, &linked_regs); + collect_linked_regs(env, this_branch, dst_reg->id, &linked_regs); if (linked_regs.cnt > 1) { err = push_jmp_history(env, this_branch, 0, linked_regs_pack(&linked_regs)); if (err) diff --git a/tools/testing/selftests/bpf/progs/exceptions_assert.c b/tools/testing/selftests/bpf/progs/exceptions_assert.c index a01c2736890f..858af5988a38 100644 --- a/tools/testing/selftests/bpf/progs/exceptions_assert.c +++ b/tools/testing/selftests/bpf/progs/exceptions_assert.c @@ -18,43 +18,43 @@ return *(u64 *)num; \ } -__msg(": R0=0xffffffff80000000") +__msg("R{{.}}=0xffffffff80000000") check_assert(s64, ==, eq_int_min, INT_MIN); -__msg(": R0=0x7fffffff") +__msg("R{{.}}=0x7fffffff") check_assert(s64, ==, eq_int_max, INT_MAX); -__msg(": R0=0") +__msg("R{{.}}=0") check_assert(s64, ==, eq_zero, 0); -__msg(": R0=0x8000000000000000 R1=0x8000000000000000") +__msg("R{{.}}=0x8000000000000000") check_assert(s64, ==, eq_llong_min, LLONG_MIN); -__msg(": R0=0x7fffffffffffffff R1=0x7fffffffffffffff") +__msg("R{{.}}=0x7fffffffffffffff") check_assert(s64, ==, eq_llong_max, LLONG_MAX); -__msg(": R0=scalar(id=1,smax=0x7ffffffe)") +__msg("R{{.}}=scalar(id=1,smax=0x7ffffffe)") check_assert(s64, <, lt_pos, INT_MAX); -__msg(": R0=scalar(id=1,smax=-1,umin=0x8000000000000000,var_off=(0x8000000000000000; 0x7fffffffffffffff))") +__msg("R{{.}}=scalar(id=1,smax=-1,umin=0x8000000000000000,var_off=(0x8000000000000000; 0x7fffffffffffffff))") check_assert(s64, <, lt_zero, 0); -__msg(": R0=scalar(id=1,smax=0xffffffff7fffffff") +__msg("R{{.}}=scalar(id=1,smax=0xffffffff7fffffff") check_assert(s64, <, lt_neg, INT_MIN); -__msg(": R0=scalar(id=1,smax=0x7fffffff)") +__msg("R{{.}}=scalar(id=1,smax=0x7fffffff)") check_assert(s64, <=, le_pos, INT_MAX); -__msg(": R0=scalar(id=1,smax=0)") +__msg("R{{.}}=scalar(id=1,smax=0)") check_assert(s64, <=, le_zero, 0); -__msg(": R0=scalar(id=1,smax=0xffffffff80000000") +__msg("R{{.}}=scalar(id=1,smax=0xffffffff80000000") check_assert(s64, <=, le_neg, INT_MIN); -__msg(": R0=scalar(id=1,smin=umin=0x80000000,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))") +__msg("R{{.}}=scalar(id=1,smin=umin=0x80000000,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))") check_assert(s64, >, gt_pos, INT_MAX); -__msg(": R0=scalar(id=1,smin=umin=1,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))") +__msg("R{{.}}=scalar(id=1,smin=umin=1,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))") check_assert(s64, >, gt_zero, 0); -__msg(": R0=scalar(id=1,smin=0xffffffff80000001") +__msg("R{{.}}=scalar(id=1,smin=0xffffffff80000001") check_assert(s64, >, gt_neg, INT_MIN); -__msg(": R0=scalar(id=1,smin=umin=0x7fffffff,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))") +__msg("R{{.}}=scalar(id=1,smin=umin=0x7fffffff,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))") check_assert(s64, >=, ge_pos, INT_MAX); -__msg(": R0=scalar(id=1,smin=0,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))") +__msg("R{{.}}=scalar(id=1,smin=0,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))") check_assert(s64, >=, ge_zero, 0); -__msg(": R0=scalar(id=1,smin=0xffffffff80000000") +__msg("R{{.}}=scalar(id=1,smin=0xffffffff80000000") check_assert(s64, >=, ge_neg, INT_MIN); SEC("?tc") diff --git a/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c b/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c index 3072fee9a448..58c7704d61cd 100644 --- a/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c +++ b/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c @@ -40,6 +40,9 @@ __naked void linked_regs_bpf_k(void) */ "r3 = r10;" "r3 += r0;" + /* Mark r1 and r2 as alive. */ + "r1 = r1;" + "r2 = r2;" "r0 = 0;" "exit;" : @@ -73,6 +76,9 @@ __naked void linked_regs_bpf_x_src(void) */ "r4 = r10;" "r4 += r0;" + /* Mark r1 and r2 as alive. */ + "r1 = r1;" + "r2 = r2;" "r0 = 0;" "exit;" : @@ -106,6 +112,10 @@ __naked void linked_regs_bpf_x_dst(void) */ "r4 = r10;" "r4 += r3;" + /* Mark r1 and r2 as alive. */ + "r0 = r0;" + "r1 = r1;" + "r2 = r2;" "r0 = 0;" "exit;" : @@ -143,6 +153,9 @@ __naked void linked_regs_broken_link(void) */ "r3 = r10;" "r3 += r0;" + /* Mark r1 and r2 as alive. */ + "r1 = r1;" + "r2 = r2;" "r0 = 0;" "exit;" : @@ -156,16 +169,16 @@ __naked void linked_regs_broken_link(void) */ SEC("socket") __success __log_level(2) -__msg("12: (0f) r2 += r1") +__msg("17: (0f) r2 += r1") /* Current state */ -__msg("frame2: last_idx 12 first_idx 11 subseq_idx -1 ") -__msg("frame2: regs=r1 stack= before 11: (bf) r2 = r10") +__msg("frame2: last_idx 17 first_idx 14 subseq_idx -1 ") +__msg("frame2: regs=r1 stack= before 16: (bf) r2 = r10") __msg("frame2: parent state regs=r1 stack=") __msg("frame1: parent state regs= stack=") __msg("frame0: parent state regs= stack=") /* Parent state */ -__msg("frame2: last_idx 10 first_idx 10 subseq_idx 11 ") -__msg("frame2: regs=r1 stack= before 10: (25) if r1 > 0x7 goto pc+0") +__msg("frame2: last_idx 13 first_idx 13 subseq_idx 14 ") +__msg("frame2: regs=r1 stack= before 13: (25) if r1 > 0x7 goto pc+0") __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 @@ -173,20 +186,20 @@ __msg("frame2: parent state regs=r1 stack=") __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") +__msg("frame2: last_idx 9 first_idx 9 subseq_idx 13") +__msg("frame2: regs=r1 stack= before 9: (85) call pc+3") /* 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: last_idx 8 first_idx 7 subseq_idx 9") +__msg("frame1: regs=r1,r6,r7 stack= before 8: (bf) r7 = r1") +__msg("frame1: regs=r1,r6 stack= before 7: (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("frame1: last_idx 4 first_idx 4 subseq_idx 7") +__msg("frame1: regs=r1 stack= before 4: (85) call pc+2") __msg("frame0: parent state regs=r1,r6 stack=") /* Parent state */ __msg("frame0: last_idx 3 first_idx 1 subseq_idx 4") @@ -204,6 +217,7 @@ __naked void precision_many_frames(void) "r1 = r0;" "r6 = r0;" "call precision_many_frames__foo;" + "r6 = r6;" /* mark r6 as live */ "exit;" : : __imm(bpf_ktime_get_ns) @@ -220,6 +234,8 @@ void precision_many_frames__foo(void) "r6 = r1;" "r7 = r1;" "call precision_many_frames__bar;" + "r6 = r6;" /* mark r6 as live */ + "r7 = r7;" /* mark r7 as live */ "exit" ::: __clobber_all); } @@ -229,6 +245,8 @@ void precision_many_frames__bar(void) { asm volatile ( "if r1 > 7 goto +0;" + "r6 = 0;" /* mark r6 as live */ + "r7 = 0;" /* mark r7 as live */ /* force r1 to be precise, this eventually marks: * - bar frame r1 * - foo frame r{1,6,7} @@ -340,6 +358,8 @@ __naked void precision_two_ids(void) "r3 += r7;" /* force r9 to be precise, this also marks r8 */ "r3 += r9;" + "r6 = r6;" /* mark r6 as live */ + "r8 = r8;" /* mark r8 as live */ "exit;" : : __imm(bpf_ktime_get_ns) @@ -353,7 +373,7 @@ __flag(BPF_F_TEST_STATE_FREQ) * collect_linked_regs() can't tie more than 6 registers for a single insn. */ __msg("8: (25) if r0 > 0x7 goto pc+0 ; R0=scalar(id=1") -__msg("9: (bf) r6 = r6 ; R6=scalar(id=2") +__msg("14: (bf) r6 = r6 ; R6=scalar(id=2") /* check that r{0-5} are marked precise after 'if' */ __msg("frame0: regs=r0 stack= before 8: (25) if r0 > 0x7 goto pc+0") __msg("frame0: parent state regs=r0,r1,r2,r3,r4,r5 stack=:") @@ -372,6 +392,12 @@ __naked void linked_regs_too_many_regs(void) "r6 = r0;" /* propagate range for r{0-6} */ "if r0 > 7 goto +0;" + /* keep r{1-5} live */ + "r1 = r1;" + "r2 = r2;" + "r3 = r3;" + "r4 = r4;" + "r5 = r5;" /* make r6 appear in the log */ "r6 = r6;" /* force r0 to be precise, @@ -517,7 +543,7 @@ __naked void check_ids_in_regsafe_2(void) "*(u64*)(r10 - 8) = r1;" /* r9 = pointer to stack */ "r9 = r10;" - "r9 += -8;" + "r9 += -16;" /* r8 = ktime_get_ns() */ "call %[bpf_ktime_get_ns];" "r8 = r0;" @@ -538,6 +564,8 @@ __naked void check_ids_in_regsafe_2(void) "if r7 > 4 goto l2_%=;" /* Access memory at r9[r6] */ "r9 += r6;" + "r9 += r7;" + "r9 += r8;" "r0 = *(u8*)(r9 + 0);" "l2_%=:" "r0 = 0;" diff --git a/tools/testing/selftests/bpf/verifier/precise.c b/tools/testing/selftests/bpf/verifier/precise.c index 061d98f6e9bb..a9242103dc47 100644 --- a/tools/testing/selftests/bpf/verifier/precise.c +++ b/tools/testing/selftests/bpf/verifier/precise.c @@ -44,9 +44,9 @@ mark_precise: frame0: regs=r2 stack= before 23\ mark_precise: frame0: regs=r2 stack= before 22\ mark_precise: frame0: regs=r2 stack= before 20\ - mark_precise: frame0: parent state regs=r2,r9 stack=:\ + mark_precise: frame0: parent state regs=r2 stack=:\ mark_precise: frame0: last_idx 19 first_idx 10\ - mark_precise: frame0: regs=r2,r9 stack= before 19\ + mark_precise: frame0: regs=r2 stack= before 19\ mark_precise: frame0: regs=r9 stack= before 18\ mark_precise: frame0: regs=r8,r9 stack= before 17\ mark_precise: frame0: regs=r0,r9 stack= before 15\ @@ -107,9 +107,9 @@ mark_precise: frame0: parent state regs=r2 stack=:\ mark_precise: frame0: last_idx 20 first_idx 20\ mark_precise: frame0: regs=r2 stack= before 20\ - mark_precise: frame0: parent state regs=r2,r9 stack=:\ + mark_precise: frame0: parent state regs=r2 stack=:\ mark_precise: frame0: last_idx 19 first_idx 17\ - mark_precise: frame0: regs=r2,r9 stack= before 19\ + mark_precise: frame0: regs=r2 stack= before 19\ mark_precise: frame0: regs=r9 stack= before 18\ mark_precise: frame0: regs=r8,r9 stack= before 17\ mark_precise: frame0: parent state regs= stack=:", -- cgit v1.2.3