From: Zijian Zhang <zijianzhang@bytedance.com> stable inclusion from stable-v5.10.230 commit 2b4530ecc01846827883fbae9738f77e7f73c1dd category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/16159 CVE: CVE-2026-63830 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 15ab0548e3107665c34579ae523b2b6e7c22082a ] Several fixes to bpf_msg_push_data, 1. test_sockmap has tests where bpf_msg_push_data is invoked to push some data at the end of a message, but -EINVAL is returned. In this case, in bpf_msg_push_data, after the first loop, i will be set to msg->sg.end, add the logic to handle it. 2. In the code block of "if (start - offset)", it's possible that "i" points to the last of sk_msg_elem. In this case, "sk_msg_iter_next(msg, end)" might still be called twice, another invoking is in "if (!copy)" code block, but actually only one is needed. Add the logic to handle it, and reconstruct the code to make the logic more clear. Fixes: 6fff607e2f14 ("bpf: sk_msg program helper bpf_msg_push_data") Signed-off-by: Zijian Zhang <zijianzhang@bytedance.com> Link: https://lore.kernel.org/r/20241106222520.527076-7-zijianzhang@bytedance.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/core/filter.c | 53 +++++++++++++++++++++++++++++------------------ 1 file changed, 33 insertions(+), 20 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index 4b501e166d62..ef4e48cb2ee7 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2773,7 +2773,7 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, sk_msg_iter_var_next(i); } while (i != msg->sg.end); - if (start >= offset + l) + if (start > offset + l) return -EINVAL; space = MAX_MSG_FRAGS - sk_msg_elem_used(msg); @@ -2798,6 +2798,8 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, raw = page_address(page); + if (i == msg->sg.end) + sk_msg_iter_var_prev(i); psge = sk_msg_elem(msg, i); front = start - offset; back = psge->length - front; @@ -2814,7 +2816,13 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, } put_page(sg_page(psge)); - } else if (start - offset) { + new = i; + goto place_new; + } + + if (start - offset) { + if (i == msg->sg.end) + sk_msg_iter_var_prev(i); psge = sk_msg_elem(msg, i); rsge = sk_msg_elem_cpy(msg, i); @@ -2825,39 +2833,44 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, sk_msg_iter_var_next(i); sg_unmark_end(psge); sg_unmark_end(&rsge); - sk_msg_iter_next(msg, end); } /* Slot(s) to place newly allocated data */ + sk_msg_iter_next(msg, end); new = i; + sk_msg_iter_var_next(i); + + if (i == msg->sg.end) { + if (!rsge.length) + goto place_new; + sk_msg_iter_next(msg, end); + goto place_new; + } /* Shift one or two slots as needed */ - if (!copy) { - sge = sk_msg_elem_cpy(msg, i); + sge = sk_msg_elem_cpy(msg, new); + sg_unmark_end(&sge); + nsge = sk_msg_elem_cpy(msg, i); + if (rsge.length) { sk_msg_iter_var_next(i); - sg_unmark_end(&sge); + nnsge = sk_msg_elem_cpy(msg, i); sk_msg_iter_next(msg, end); + } - nsge = sk_msg_elem_cpy(msg, i); + while (i != msg->sg.end) { + msg->sg.data[i] = sge; + sge = nsge; + sk_msg_iter_var_next(i); if (rsge.length) { - sk_msg_iter_var_next(i); + nsge = nnsge; nnsge = sk_msg_elem_cpy(msg, i); - } - - while (i != msg->sg.end) { - msg->sg.data[i] = sge; - sge = nsge; - sk_msg_iter_var_next(i); - if (rsge.length) { - nsge = nnsge; - nnsge = sk_msg_elem_cpy(msg, i); - } else { - nsge = sk_msg_elem_cpy(msg, i); - } + } else { + nsge = sk_msg_elem_cpy(msg, i); } } +place_new: /* Place newly allocated data buffer */ sk_mem_charge(msg->sk, len); msg->sg.size += len; -- 2.43.0