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(unknown [202.112.238.121]) by web4 (Coremail) with SMTP id ywQGZQCnbKE5gUNqiZafAg--.37989S2; Tue, 30 Jun 2026 16:41:47 +0800 (CST) From: Yiyang Chen To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi Cc: Yiyang Chen , John Fastabend , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Shuah Khan , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v3 0/2] bpf: Reject MEM_ALLOC BTF accesses past bounds Date: Tue, 30 Jun 2026 08:41:25 +0000 Message-Id: X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:ywQGZQCnbKE5gUNqiZafAg--.37989S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Ww1UXryxJF4xJr15CF15Jwb_yoW8XryUpF WrJw1fAFW0vrWxZFnIya129rn8tay8Xr15G3WfK348ur1YyF1UXrWkKr1Yyr90y3sF9F15 uFy09F9xG3W7uwUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUP014x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1lnxkEFVAIw20F6cxK64vIFxWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xv F2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r 4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I 648v4I1lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AFwI0_Jw0_GFylc2xSY4AK67 AK6r43MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAF wI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc4 0Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AK xVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr 1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUjXTm3UU UUU== X-CM-SenderInfo: xfkh05r1stqzpdlo2hxwvl0wxkxdhvlgxou0/ BTF struct walks can relax the top-level struct-size check for trailing flexible arrays. That relaxation must not let a PTR_TO_BTF_ID | MEM_ALLOC access escape the bytes allocated by bpf_obj_new() or bpf_percpu_obj_new(). Patch 1 rejects MEM_ALLOC BTF walks whose access range reaches past the current struct size before applying the flexible-array relaxation. This now also applies to struct ID matching used by kfunc and kptr type checks. Patch 2 adds a linked_list negative loader case for this path. Changes in v3: - Pass the flexible-array walk policy through btf_struct_ids_match() callers, so MEM_ALLOC kfunc/kptr type checks use the same bounds rule. - Rename the btf_struct_walk() parameter to walk_flex_arrays. - Rebase onto current bpf-next. v2: https://lore.kernel.org/bpf/cover.1782197377.git.chenyy23@mails.tsinghua.edu.cn/ v1: https://lore.kernel.org/bpf/cover.1782100805.git.chenyy23@mails.tsinghua.edu.cn/ Yiyang Chen (2): bpf: Reject MEM_ALLOC BTF accesses past object bounds selftests/bpf: Cover MEM_ALLOC access past object bounds include/linux/bpf.h | 2 +- kernel/bpf/btf.c | 17 +++++++++----- kernel/bpf/verifier.c | 11 +++++---- .../selftests/bpf/prog_tests/linked_list.c | 1 + .../selftests/bpf/progs/linked_list_fail.c | 23 +++++++++++++++++++ 5 files changed, 43 insertions(+), 11 deletions(-) base-commit: 53435562a725962e4de0c29653223129ba11643a -- 2.34.1