[PATCH OLK-6.6 0/2] CVE-2026-53090
Daniel Borkmann (2): bpf: Fix ld_{abs,ind} failure path analysis in subprogs selftests/bpf: Add tests for ld_{abs,ind} failure path in subprogs kernel/bpf/verifier.c | 17 +++ .../selftests/bpf/progs/verifier_ld_ind.c | 142 ++++++++++++++++++ 2 files changed, 159 insertions(+) -- 2.34.1
From: Daniel Borkmann <daniel@iogearbox.net> mainline inclusion from mainline-v7.1-rc1 commit ee861486e377edc55361c08dcbceab3f6b6577bd category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15793 CVE: CVE-2026-53090 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Usage of ld_{abs,ind} instructions got extended into subprogs some time ago via commit 09b28d76eac4 ("bpf: Add abnormal return checks."). These are only allowed in subprograms when the latter are BTF annotated and have scalar return types. The code generator in bpf_gen_ld_abs() has an abnormal exit path (r0=0 + exit) from legacy cBPF times. While the enforcement is on scalar return types, the verifier must also simulate the path of abnormal exit if the packet data load via ld_{abs,ind} failed. This is currently not the case. Fix it by having the verifier simulate both success and failure paths, and extend it in similar ways as we do for tail calls. The success path (r0=unknown, continue to next insn) is pushed onto stack for later validation and the r0=0 and return to the caller is done on the fall-through side. Fixes: 09b28d76eac4 ("bpf: Add abnormal return checks.") Reported-by: STAR Labs SG <info@starlabs.sg> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/20260408191242.526279-2-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org> Conflicts: kernel/bpf/verifier.c [The current version does not introduce consumers corresponding to the output of jump tables; therefore, the assignment of jump tables is not involved.] Signed-off-by: Pu Lehui <pulehui@huawei.com> --- kernel/bpf/verifier.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6977c3657381..1396eae6b85c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -15274,6 +15274,23 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) mark_reg_unknown(env, regs, BPF_REG_0); /* ld_abs load up to 32-bit skb data. */ regs[BPF_REG_0].subreg_def = env->insn_idx + 1; + /* + * See bpf_gen_ld_abs() which emits a hidden BPF_EXIT with r0=0 + * which must be explored by the verifier when in a subprog. + */ + if (env->cur_state->curframe) { + struct bpf_verifier_state *branch; + + mark_reg_scratched(env, BPF_REG_0); + branch = push_stack(env, env->insn_idx + 1, env->insn_idx, false); + if (IS_ERR(branch)) + return PTR_ERR(branch); + mark_reg_known_zero(env, regs, BPF_REG_0); + err = prepare_func_exit(env, &env->insn_idx); + if (err) + return err; + env->insn_idx--; + } return 0; } -- 2.34.1
From: Daniel Borkmann <daniel@iogearbox.net> mainline inclusion from mainline-v7.1-rc1 commit e0fcb42bc6f41bab2895757d6610616b3820eff7 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15793 CVE: CVE-2026-53090 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Extend the verifier_ld_ind BPF selftests with subprogs containing ld_{abs,ind} and craft the test in a way where the invalid register read is rejected in the fixed case. Also add a success case each, and add additional coverage related to the BTF return type enforcement. # LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh -- ./test_progs -t verifier_ld_ind [...] #611/1 verifier_ld_ind/ld_ind: check calling conv, r1:OK #611/2 verifier_ld_ind/ld_ind: check calling conv, r1 @unpriv:OK #611/3 verifier_ld_ind/ld_ind: check calling conv, r2:OK #611/4 verifier_ld_ind/ld_ind: check calling conv, r2 @unpriv:OK #611/5 verifier_ld_ind/ld_ind: check calling conv, r3:OK #611/6 verifier_ld_ind/ld_ind: check calling conv, r3 @unpriv:OK #611/7 verifier_ld_ind/ld_ind: check calling conv, r4:OK #611/8 verifier_ld_ind/ld_ind: check calling conv, r4 @unpriv:OK #611/9 verifier_ld_ind/ld_ind: check calling conv, r5:OK #611/10 verifier_ld_ind/ld_ind: check calling conv, r5 @unpriv:OK #611/11 verifier_ld_ind/ld_ind: check calling conv, r7:OK #611/12 verifier_ld_ind/ld_ind: check calling conv, r7 @unpriv:OK #611/13 verifier_ld_ind/ld_abs: subprog early exit on ld_abs failure:OK #611/14 verifier_ld_ind/ld_ind: subprog early exit on ld_ind failure:OK #611/15 verifier_ld_ind/ld_abs: subprog with both paths safe:OK #611/16 verifier_ld_ind/ld_ind: subprog with both paths safe:OK #611/17 verifier_ld_ind/ld_abs: reject void return subprog:OK #611/18 verifier_ld_ind/ld_ind: reject void return subprog:OK #611 verifier_ld_ind:OK Summary: 1/18 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/20260408191242.526279-4-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Pu Lehui <pulehui@huawei.com> --- .../selftests/bpf/progs/verifier_ld_ind.c | 142 ++++++++++++++++++ 1 file changed, 142 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_ld_ind.c b/tools/testing/selftests/bpf/progs/verifier_ld_ind.c index c925ba9a2e74..09e81b99eecb 100644 --- a/tools/testing/selftests/bpf/progs/verifier_ld_ind.c +++ b/tools/testing/selftests/bpf/progs/verifier_ld_ind.c @@ -107,4 +107,146 @@ __naked void ind_check_calling_conv_r7(void) : __clobber_all); } +/* + * ld_{abs,ind} subprog that always sets r0=1 on the success path. + * bpf_gen_ld_abs() emits a hidden exit with r0=0 when the load helper + * fails. The verifier must model this failure return so that callers + * account for r0=0 as a possible return value. + */ +__naked __noinline __used +static int ldabs_subprog(void) +{ + asm volatile ( + "r6 = r1;" + ".8byte %[ld_abs];" + "r0 = 1;" + "exit;" + : + : __imm_insn(ld_abs, BPF_LD_ABS(BPF_W, 0)) + : __clobber_all); +} + +__naked __noinline __used +static int ldind_subprog(void) +{ + asm volatile ( + "r6 = r1;" + "r7 = 0;" + ".8byte %[ld_ind];" + "r0 = 1;" + "exit;" + : + : __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_7, 0)) + : __clobber_all); +} + +SEC("socket") +__description("ld_abs: subprog early exit on ld_abs failure") +__failure __msg("R9 !read_ok") +__naked void ld_abs_subprog_early_exit(void) +{ + asm volatile ( + "call ldabs_subprog;" + "if r0 != 0 goto l_exit_%=;" + "r0 = r9;" + "l_exit_%=:" + "r0 = 0;" + "exit;" + ::: __clobber_all); +} + +SEC("socket") +__description("ld_ind: subprog early exit on ld_ind failure") +__failure __msg("R9 !read_ok") +__naked void ld_ind_subprog_early_exit(void) +{ + asm volatile ( + "call ldind_subprog;" + "if r0 != 0 goto l_exit_%=;" + "r0 = r9;" + "l_exit_%=:" + "r0 = 0;" + "exit;" + ::: __clobber_all); +} + +SEC("socket") +__description("ld_abs: subprog with both paths safe") +__success +__naked void ld_abs_subprog_both_paths_safe(void) +{ + asm volatile ( + "call ldabs_subprog;" + "r0 = 0;" + "exit;" + ::: __clobber_all); +} + +SEC("socket") +__description("ld_ind: subprog with both paths safe") +__success +__naked void ld_ind_subprog_both_paths_safe(void) +{ + asm volatile ( + "call ldind_subprog;" + "r0 = 0;" + "exit;" + ::: __clobber_all); +} + +/* + * ld_{abs,ind} in subprogs require scalar (int) return type in BTF. + * A test with void return must be rejected. + */ +__naked __noinline __used +static void ldabs_void_subprog(void) +{ + asm volatile ( + "r6 = r1;" + ".8byte %[ld_abs];" + "r0 = 1;" + "exit;" + : + : __imm_insn(ld_abs, BPF_LD_ABS(BPF_W, 0)) + : __clobber_all); +} + +SEC("socket") +__description("ld_abs: reject void return subprog") +__failure __msg("LD_ABS is only allowed in functions that return 'int'") +__naked void ld_abs_void_subprog_reject(void) +{ + asm volatile ( + "call ldabs_void_subprog;" + "r0 = 0;" + "exit;" + ::: __clobber_all); +} + +__naked __noinline __used +static void ldind_void_subprog(void) +{ + asm volatile ( + "r6 = r1;" + "r7 = 0;" + ".8byte %[ld_ind];" + "r0 = 1;" + "exit;" + : + : __imm_insn(ld_ind, BPF_LD_IND(BPF_W, BPF_REG_7, 0)) + : __clobber_all); +} + +SEC("socket") +__description("ld_ind: reject void return subprog") +__failure __msg("LD_ABS is only allowed in functions that return 'int'") +__naked void ld_ind_void_subprog_reject(void) +{ + asm volatile ( + "call ldind_void_subprog;" + "r0 = 0;" + "exit;" + ::: __clobber_all); +} + char _license[] SEC("license") = "GPL"; -- 2.34.1
反馈： 您发送到kernel@openeuler.org的补丁/补丁集，已成功转换为PR！ PR链接地址： https://atomgit.com/openeuler/kernel/merge_requests/24695 邮件列表地址：https://mailweb.openeuler.org/archives/list/kernel@openeuler.org/message/O5V... FeedBack: The patch(es) which you have sent to kernel@openeuler.org mailing list has been converted to a pull request successfully! Pull request link: https://atomgit.com/openeuler/kernel/merge_requests/24695 Mailing list address: https://mailweb.openeuler.org/archives/list/kernel@openeuler.org/message/O5V...
participants (2)
-
patchwork bot -
Pu Lehui