From: Amery Hung <ameryhung@gmail.com> stable inclusion from stable-v6.6.121 commit d08b4193cd55adbbf3700cdd777e5b2054ad1485 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13686 CVE: CVE-2026-23140 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit fe9544ed1a2e9217b2c5285c3a4ac0dc5a38bd7b ] To test bpf_xdp_pull_data(), an xdp packet containing fragments as well as free linear data area after xdp->data_end needs to be created. However, bpf_prog_test_run_xdp() always fills the linear area with data_in before creating fragments, leaving no space to pull data. This patch will allow users to specify the linear data size through ctx->data_end. Currently, ctx_in->data_end must match data_size_in and will not be the final ctx->data_end seen by xdp programs. This is because ctx->data_end is populated according to the xdp_buff passed to test_run. The linear data area available in an xdp_buff, max_linear_sz, is alawys filled up before copying data_in into fragments. This patch will allow users to specify the size of data that goes into the linear area. When ctx_in->data_end is different from data_size_in, only ctx_in->data_end bytes of data will be put into the linear area when creating the xdp_buff. While ctx_in->data_end will be allowed to be different from data_size_in, it cannot be larger than the data_size_in as there will be no data to copy from user space. If it is larger than the maximum linear data area size, the layout suggested by the user will not be honored. Data beyond max_linear_sz bytes will still be copied into fragments. Finally, since it is possible for a NIC to produce a xdp_buff with empty linear data area, allow it when calling bpf_test_init() from bpf_prog_test_run_xdp() so that we can test XDP kfuncs with such xdp_buff. This is done by moving lower-bound check to callers as most of them already do except bpf_prog_test_run_skb(). The change also fixes a bug that allows passing an xdp_buff with data < ETH_HLEN. This can happen when ctx is used and metadata is at least ETH_HLEN. Signed-off-by: Amery Hung <ameryhung@gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://patch.msgid.link/20250922233356.3356453-7-ameryhung@gmail.com Stable-dep-of: e558cca21779 ("bpf, test_run: Subtract size of xdp_frame from allowed metadata size") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Li Xiasong <lixiasong1@huawei.com> --- net/bpf/test_run.c | 15 ++++++++++++--- .../bpf/prog_tests/xdp_context_test_run.c | 4 +--- 2 files changed, 13 insertions(+), 6 deletions(-) diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 10b4f3df014b..e036964a3500 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -630,7 +630,7 @@ static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size, void __user *data_in = u64_to_user_ptr(kattr->test.data_in); void *data; - if (user_size < ETH_HLEN || user_size > PAGE_SIZE - headroom - tailroom) + if (user_size > PAGE_SIZE - headroom - tailroom) return ERR_PTR(-EINVAL); size = SKB_DATA_ALIGN(size); @@ -969,6 +969,9 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr, if (kattr->test.flags || kattr->test.cpu || kattr->test.batch_size) return -EINVAL; + if (size < ETH_HLEN) + return -EINVAL; + data = bpf_test_init(kattr, kattr->test.data_size_in, size, NET_SKB_PAD + NET_IP_ALIGN, SKB_DATA_ALIGN(sizeof(struct skb_shared_info))); @@ -1149,7 +1152,7 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, { bool do_live = (kattr->test.flags & BPF_F_TEST_XDP_LIVE_FRAMES); u32 tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); - u32 retval = 0, duration, max_linear_sz, size; + u32 retval = 0, meta_sz = 0, duration, max_linear_sz, size; u32 linear_sz = kattr->test.data_size_in; u32 batch_size = kattr->test.batch_size; u32 headroom = XDP_PACKET_HEADROOM; @@ -1188,13 +1191,16 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, if (ctx) { /* There can't be user provided data before the meta data */ - if (ctx->data_meta || ctx->data_end != kattr->test.data_size_in || + if (ctx->data_meta || ctx->data_end > kattr->test.data_size_in || ctx->data > ctx->data_end || unlikely(xdp_metalen_invalid(ctx->data)) || (do_live && (kattr->test.data_out || kattr->test.ctx_out))) goto free_ctx; /* Meta data is allocated from the headroom */ headroom -= ctx->data; + + meta_sz = ctx->data; + linear_sz = ctx->data_end; } max_linear_sz = PAGE_SIZE - headroom - tailroom; @@ -1204,6 +1210,9 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, if (do_live && kattr->test.data_size_in > linear_sz) goto free_ctx; + if (kattr->test.data_size_in - meta_sz < ETH_HLEN) + return -EINVAL; + data = bpf_test_init(kattr, linear_sz, max_linear_sz, headroom, tailroom); if (IS_ERR(data)) { ret = PTR_ERR(data); diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c index ab4952b9fb1d..eab8625aad3b 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c @@ -80,9 +80,7 @@ void test_xdp_context_test_run(void) /* Meta data must be 32 bytes or smaller */ test_xdp_context_error(prog_fd, opts, 0, 36, sizeof(data), 0, 0, 0); - /* Total size of data must match data_end - data_meta */ - test_xdp_context_error(prog_fd, opts, 0, sizeof(__u32), - sizeof(data) - 1, 0, 0, 0); + /* Total size of data must be data_end - data_meta or larger */ test_xdp_context_error(prog_fd, opts, 0, sizeof(__u32), sizeof(data) + 1, 0, 0, 0); -- 2.34.1