From 4314a44564eb1565349fed7a4192344c5f46fc85 Mon Sep 17 00:00:00 2001 From: Yazhou Tang Date: Wed, 6 May 2026 17:47:12 +0800 Subject: bpf: Fix out-of-bounds read in bpf_patch_call_args() The interpreters_args array only accommodates stack depths up to MAX_BPF_STACK (512 bytes). However, do_misc_fixups() may allow a larger stack depth if JIT is requested. If JIT compilation later fails and falls back to the interpreter, the verifier invokes bpf_patch_call_args() with this oversized stack depth. This causes a load-time out-of-bounds (OOB) read when calculating the interpreter function pointer index. Fix this by changing bpf_patch_call_args() to return an int and explicitly rejecting the JIT fallback (returning -EINVAL) if the stack depth exceeds MAX_BPF_STACK. Fixes: 1ea47e01ad6e ("bpf: add support for bpf_call to interpreter") Co-developed-by: Tianci Cao Signed-off-by: Tianci Cao Co-developed-by: Shenghao Yuan Signed-off-by: Shenghao Yuan Signed-off-by: Yazhou Tang Acked-by: Xu Kuohai Link: https://lore.kernel.org/r/20260506094714.419842-2-tangyazhou@zju.edu.cn Signed-off-by: Alexei Starovoitov --- kernel/bpf/core.c | 6 +++++- kernel/bpf/fixups.c | 7 ++++++- 2 files changed, 11 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 8b018ff48875..63044ebe5721 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2394,13 +2394,17 @@ EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) #undef PROG_NAME_LIST #ifdef CONFIG_BPF_SYSCALL -void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) +int bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) { stack_depth = max_t(u32, stack_depth, 1); + /* Prevent out-of-bounds read to interpreters_args */ + if (stack_depth > MAX_BPF_STACK) + return -EINVAL; insn->off = (s16) insn->imm; insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - __bpf_call_base_args; insn->code = BPF_JMP | BPF_CALL_ARGS; + return 0; } #endif #endif diff --git a/kernel/bpf/fixups.c b/kernel/bpf/fixups.c index fba9e8c00878..df8f48091321 100644 --- a/kernel/bpf/fixups.c +++ b/kernel/bpf/fixups.c @@ -1416,7 +1416,12 @@ int bpf_fixup_call_args(struct bpf_verifier_env *env) depth = get_callee_stack_depth(env, insn, i); if (depth < 0) return depth; - bpf_patch_call_args(insn, depth); + err = bpf_patch_call_args(insn, depth); + if (err) { + verbose(env, "stack depth %d exceeds interpreter stack depth limit\n", + depth); + return err; + } } err = 0; #endif -- cgit v1.2.3 From 58a8f3e2501dc14b8e00e883d6aaf0600a239da7 Mon Sep 17 00:00:00 2001 From: Yazhou Tang Date: Wed, 6 May 2026 17:47:13 +0800 Subject: bpf: Fix s16 truncation for large bpf-to-bpf call offsets Currently, the BPF instruction set allows bpf-to-bpf calls (or internal calls, pseudo calls) to use a 32-bit imm field to represent the relative jump offset. However, when JIT is disabled or falls back to the interpreter, the verifier invokes bpf_patch_call_args() to rewrite the call instruction. In this function, the 32-bit imm is downcast to s16 and stored in the off field. void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) { stack_depth = max_t(u32, stack_depth, 1); insn->off = (s16) insn->imm; insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - __bpf_call_base_args; insn->code = BPF_JMP | BPF_CALL_ARGS; } If the original imm exceeds the s16 range (i.e., a jump offset greater than 32767 instructions), this downcast silently truncates the offset, resulting in an incorrect call target. Fix this by: 1. In bpf_patch_call_args(), keeping the imm field unchanged and using the off field to store the index of the interpreter function. 2. In ___bpf_prog_run() for the JMP_CALL_ARGS case, retrieving the interpreter function pointer from the interpreters_args array using the off field as the index, and passing the original imm to calculate the last argument of the interpreter function. After these changes, the truncation issue is resolved, and __bpf_call_base_args is also no longer needed and can be removed, which makes the code cleaner. Performance: In ___bpf_prog_run() for the JMP_CALL_ARGS case, changing the retrieval of the interpreter function pointer from pointer addition to direct array indexing improves performance. The possible reason is that the latter has better instruction-level parallelism. See the v5 discussion [1] for more details. [1] https://lore.kernel.org/bpf/f120c3c4-6999-414a-b514-518bb64b4758@zju.edu.cn/ To avoid requiring bpftool changes, keep the new imm/off encoding internal and restore the legacy xlated dump layout in bpf_insn_prepare_dump(). For bpf-to-bpf call offsets that do not fit in s16, export off as 0 instead of a truncated and misleading value. Fixes: 1ea47e01ad6e ("bpf: add support for bpf_call to interpreter") Fixes: 7105e828c087 ("bpf: allow for correlation of maps and helpers in dump") Suggested-by: Xu Kuohai Suggested-by: Puranjay Mohan Co-developed-by: Tianci Cao Signed-off-by: Tianci Cao Co-developed-by: Shenghao Yuan Signed-off-by: Shenghao Yuan Signed-off-by: Yazhou Tang Link: https://lore.kernel.org/r/20260506094714.419842-3-tangyazhou@zju.edu.cn Signed-off-by: Alexei Starovoitov --- kernel/bpf/core.c | 21 ++++++++++++++------- kernel/bpf/fixups.c | 6 +++--- kernel/bpf/syscall.c | 26 ++++++++++++++++++++++++++ 3 files changed, 43 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 63044ebe5721..6aa2a8b24030 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1771,6 +1771,9 @@ static u32 abs_s32(s32 x) return x >= 0 ? (u32)x : -(u32)x; } +static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, + const struct bpf_insn *insn); + /** * ___bpf_prog_run - run eBPF program on a given context * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers @@ -2077,10 +2080,9 @@ select_insn: CONT; JMP_CALL_ARGS: - BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, - BPF_R3, BPF_R4, - BPF_R5, - insn + insn->off + 1); + BPF_R0 = interpreters_args[insn->off](BPF_R1, BPF_R2, BPF_R3, + BPF_R4, BPF_R5, + insn + insn->imm + 1); CONT; JMP_TAIL_CALL: { @@ -2400,12 +2402,17 @@ int bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) /* Prevent out-of-bounds read to interpreters_args */ if (stack_depth > MAX_BPF_STACK) return -EINVAL; - insn->off = (s16) insn->imm; - insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - - __bpf_call_base_args; + insn->off = (round_up(stack_depth, 32) / 32) - 1; insn->code = BPF_JMP | BPF_CALL_ARGS; return 0; } + +s32 bpf_call_args_imm(s16 idx) +{ + if (WARN_ON_ONCE(idx < 0 || idx >= ARRAY_SIZE(interpreters_args))) + return 0; + return BPF_CALL_IMM(interpreters_args[idx]); +} #endif #endif diff --git a/kernel/bpf/fixups.c b/kernel/bpf/fixups.c index df8f48091321..3692adf62558 100644 --- a/kernel/bpf/fixups.c +++ b/kernel/bpf/fixups.c @@ -1250,9 +1250,9 @@ static int jit_subprogs(struct bpf_verifier_env *env) } if (!bpf_pseudo_call(insn)) continue; - insn->off = env->insn_aux_data[i].call_imm; - subprog = bpf_find_subprog(env, i + insn->off + 1); - insn->imm = subprog; + insn->imm = env->insn_aux_data[i].call_imm; + subprog = bpf_find_subprog(env, i + insn->imm + 1); + insn->off = subprog; } prog->jited = 1; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a3c0214ca934..630d530782fe 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4919,6 +4919,29 @@ out: return map; } +static void prepare_dump_pseudo_call(struct bpf_insn *insn) +{ + s32 call_off = insn->imm; + + /* + * BPF_CALL_ARGS only exists for interpreter fallback. + * 1. For interpreter (BPF_CALL_ARGS): insn->off is the index of + * interpreters_args array, so here using bpf_call_args_imm() + * to get the real address offset. + * 2. For JIT (BPF_CALL): insn->off is the subprog id. + */ + if (insn->code == (BPF_JMP | BPF_CALL_ARGS)) + insn->imm = bpf_call_args_imm(insn->off); + else + insn->imm = insn->off; + + /* Avoid dumping a truncated and misleading pc-relative offset. */ + if (call_off > S16_MAX || call_off < S16_MIN) + insn->off = 0; + else + insn->off = call_off; +} + static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog, const struct cred *f_cred) { @@ -4944,6 +4967,9 @@ static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog, } if (code == (BPF_JMP | BPF_CALL) || code == (BPF_JMP | BPF_CALL_ARGS)) { + /* Restore the legacy xlated dump layout. */ + if (insns[i].src_reg == BPF_PSEUDO_CALL) + prepare_dump_pseudo_call(&insns[i]); if (code == (BPF_JMP | BPF_CALL_ARGS)) insns[i].code = BPF_JMP | BPF_CALL; if (!bpf_dump_raw_ok(f_cred)) -- cgit v1.2.3 From 593980175389a05793f6060aa20e626330960395 Mon Sep 17 00:00:00 2001 From: Guannan Wang Date: Thu, 14 May 2026 15:44:54 +0800 Subject: bpf: Use array_map_meta_equal for percpu array inner map replacement percpu_array_map_ops.map_meta_equal points to the generic bpf_map_meta_equal(), which does not compare max_entries. When a percpu array serves as an inner map, replacing it with one that has fewer max_entries bypasses the check. Since percpu_array_map_gen_lookup() inlines the original template's index_mask as a JIT immediate, a lookup on the replacement map can access pptrs[] out of bounds. Point percpu_array_map_ops.map_meta_equal to array_map_meta_equal(), which already enforces the max_entries equality check. Add a selftest to verify that replacing a percpu array inner map with a differently-sized one is rejected. Fixes: db69718b8efa ("bpf: inline bpf_map_lookup_elem() for PERCPU_ARRAY maps") Signed-off-by: Guannan Wang Acked-by: Mykyta Yatsenko Link: https://lore.kernel.org/r/20260514074454.77491-1-wgnbuaa@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/arraymap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 5e25e0353509..dfb2110ab733 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -827,7 +827,7 @@ const struct bpf_map_ops array_map_ops = { }; const struct bpf_map_ops percpu_array_map_ops = { - .map_meta_equal = bpf_map_meta_equal, + .map_meta_equal = array_map_meta_equal, .map_alloc_check = array_map_alloc_check, .map_alloc = array_map_alloc, .map_free = array_map_free, -- cgit v1.2.3 From a828abbb897657451d96ad7bf20f1893ac983bb9 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 15 May 2026 13:32:32 +0200 Subject: bpf: make bpf_session_is_return() reference optional Building without CONFIG_BPF_EVENTS produces a build-time warning: WARN: resolve_btfids: unresolved symbol bpf_session_is_return The function is actually defined in kernel/trace/bpf_trace.o, which is built conditionally based on configuration. Make the reference to this function conditional as well, as is already done in the bpf verifier for other functions. Fixes: 8fe4dc4f6456 ("bpf: change prototype of bpf_session_{cookie,is_return}") Signed-off-by: Arnd Bergmann Link: https://lore.kernel.org/r/20260515113242.2706303-1-arnd@kernel.org Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 69d75515ed3f..88b40c979b56 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -11263,7 +11263,11 @@ BTF_ID(func, bpf_task_work_schedule_resume) BTF_ID(func, bpf_arena_alloc_pages) BTF_ID(func, bpf_arena_free_pages) BTF_ID(func, bpf_arena_reserve_pages) +#ifdef CONFIG_BPF_EVENTS BTF_ID(func, bpf_session_is_return) +#else +BTF_ID_UNUSED +#endif BTF_ID(func, bpf_stream_vprintk) BTF_ID(func, bpf_stream_print_stack) -- cgit v1.2.3 From 3d562d35a044ae798cab421c65a116f8cedfa5d4 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Sun, 17 May 2026 09:55:28 +0200 Subject: bpf: Check global subprog exception paths Global subprogs are verified independently and are not descended into when their callers are symbolically executed. This means a caller can hold references or locks across a global subprog call that may throw, while the verifier only checks the non-exceptional return path at the call site. Record whether a subprog might throw in the CFG summary pass, alongside the existing might_sleep and packet-data-changing summaries, and propagate that effect through reachable callees. When a global subprog is marked as possibly throwing, push the normal continuation and validate the exceptional path immediately at the call site, avoiding a synthetic exception state and associated special case in the pruning checks. Fixes: f18b03fabaa9 ("bpf: Implement BPF exceptions") Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260517075530.3461166-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/cfg.c | 13 ++++++++++++- kernel/bpf/verifier.c | 23 +++++++++++++++++------ 2 files changed, 29 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/cfg.c b/kernel/bpf/cfg.c index 998f42a8189a..26d37066465f 100644 --- a/kernel/bpf/cfg.c +++ b/kernel/bpf/cfg.c @@ -64,11 +64,19 @@ static void mark_subprog_might_sleep(struct bpf_verifier_env *env, int off) subprog->might_sleep = true; } +static void mark_subprog_might_throw(struct bpf_verifier_env *env, int off) +{ + struct bpf_subprog_info *subprog; + + subprog = bpf_find_containing_subprog(env, off); + subprog->might_throw = true; +} + /* 't' is an index of a call-site. * 'w' is a callee entry point. * Eventually this function would be called when env->cfg.insn_state[w] == EXPLORED. * Rely on DFS traversal order and absence of recursive calls to guarantee that - * callee's change_pkt_data marks would be correct at that moment. + * callee's effect marks would be correct at that moment. */ static void merge_callee_effects(struct bpf_verifier_env *env, int t, int w) { @@ -78,6 +86,7 @@ static void merge_callee_effects(struct bpf_verifier_env *env, int t, int w) callee = bpf_find_containing_subprog(env, w); caller->changes_pkt_data |= callee->changes_pkt_data; caller->might_sleep |= callee->might_sleep; + caller->might_throw |= callee->might_throw; } enum { @@ -509,6 +518,8 @@ static int visit_insn(int t, struct bpf_verifier_env *env) mark_subprog_might_sleep(env, t); if (ret == 0 && bpf_is_kfunc_pkt_changing(&meta)) mark_subprog_changes_pkt_data(env, t); + if (ret == 0 && bpf_is_throw_kfunc(insn)) + mark_subprog_might_throw(env, t); } return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 88b40c979b56..7fb88e1cd7c4 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -442,7 +442,6 @@ static bool is_dynptr_ref_function(enum bpf_func_id func_id) static bool is_sync_callback_calling_kfunc(u32 btf_id); static bool is_async_callback_calling_kfunc(u32 btf_id); static bool is_callback_calling_kfunc(u32 btf_id); -static bool is_bpf_throw_kfunc(struct bpf_insn *insn); static bool is_bpf_wq_set_callback_kfunc(u32 btf_id); static bool is_task_work_add_kfunc(u32 func_id); @@ -5405,7 +5404,7 @@ continue_func: if (bpf_pseudo_kfunc_call(insn + i) && !insn[i].off) { bool err = false; - if (!is_bpf_throw_kfunc(insn + i)) + if (!bpf_is_throw_kfunc(insn + i)) continue; for (tmp = idx; tmp >= 0 && !err; tmp = dinfo[tmp].caller) { if (subprog[tmp].is_cb) { @@ -9499,6 +9498,9 @@ static int push_callback_call(struct bpf_verifier_env *env, struct bpf_insn *ins return 0; } +static int process_bpf_exit_full(struct bpf_verifier_env *env, + bool *do_print_state, bool exception_exit); + static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, int *insn_idx) { @@ -9552,6 +9554,17 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG; } + if (env->subprog_info[subprog].might_throw) { + struct bpf_verifier_state *branch; + + branch = push_stack(env, *insn_idx + 1, *insn_idx, false); + if (IS_ERR(branch)) { + verbose(env, "failed to push state for global subprog exception path\n"); + return PTR_ERR(branch); + } + return process_bpf_exit_full(env, NULL, true); + } + /* continue with next insn after call */ return 0; } @@ -11782,7 +11795,7 @@ static bool is_async_callback_calling_kfunc(u32 btf_id) is_task_work_add_kfunc(btf_id); } -static bool is_bpf_throw_kfunc(struct bpf_insn *insn) +bool bpf_is_throw_kfunc(struct bpf_insn *insn) { return bpf_pseudo_kfunc_call(insn) && insn->off == 0 && insn->imm == special_kfunc_list[KF_bpf_throw]; @@ -12972,8 +12985,6 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca } static int check_return_code(struct bpf_verifier_env *env, int regno, const char *reg_name); -static int process_bpf_exit_full(struct bpf_verifier_env *env, - bool *do_print_state, bool exception_exit); static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, int *insn_idx_p) @@ -13354,7 +13365,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (meta.func_id == special_kfunc_list[KF_bpf_session_cookie]) env->prog->call_session_cookie = true; - if (is_bpf_throw_kfunc(insn)) + if (bpf_is_throw_kfunc(insn)) return process_bpf_exit_full(env, NULL, true); return 0; -- cgit v1.2.3 From 49b18315be4eecfc36b75f4aecb4d40a87d68a20 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Wed, 20 May 2026 04:40:59 +0200 Subject: bpf: Reject NULL data/sig in bpf_verify_pkcs7_signature __bpf_dynptr_data() can return NULL (FILE dynptrs, any non-contiguous backing). bpf_verify_pkcs7_signature() forwards the pointer to verify_pkcs7_signature() unchecked, causing a NULL deref in asn1_ber_decoder() reachable from a sleepable BPF LSM at lsm.s/bpf. NULL-check both pointers and reject with -EINVAL. Mirrors the guards already in kernel/bpf/crypto.c. Fixes: 865b0566d8f1 ("bpf: Add bpf_verify_pkcs7_signature() kfunc") Reported-by: Xianrui Dong Signed-off-by: KP Singh Reviewed-by: Amery Hung Acked-by: Song Liu Acked-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20260520024059.313468-1-kpsingh@kernel.org Signed-off-by: Kumar Kartikeya Dwivedi --- kernel/bpf/helpers.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 2bb60200c266..b5314c9fed3c 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -4241,8 +4241,13 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_p, data_len = __bpf_dynptr_size(data_ptr); data = __bpf_dynptr_data(data_ptr, data_len); + if (!data) + return -EINVAL; + sig_len = __bpf_dynptr_size(sig_ptr); sig = __bpf_dynptr_data(sig_ptr, sig_len); + if (!sig) + return -EINVAL; return verify_pkcs7_signature(data, data_len, sig, sig_len, trusted_keyring->key, -- cgit v1.2.3