From: Eric Dumazet <edumazet@google.com> maillist inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8ZTOK Reference: https://lore.kernel.org/all/20240125103317.2334989-1-edumazet@google.com/ -------------------------------- TCP rx zerocopy intent is to map pages initially allocated from NIC drivers, not pages owned by a fs. This patch adds to can_map_frag() these additional checks: - Page must not be a compound one. - page->mapping must be NULL. This fixes the panic reported by ZhangPeng. syzbot was able to loopback packets built with sendfile(), mapping pages owned by an ext4 file to TCP rx zerocopy. r3 = socket$inet_tcp(0x2, 0x1, 0x0) mmap(&(0x7f0000ff9000/0x4000)=nil, 0x4000, 0x0, 0x12, r3, 0x0) r4 = socket$inet_tcp(0x2, 0x1, 0x0) bind$inet(r4, &(0x7f0000000000)={0x2, 0x4e24, @multicast1}, 0x10) connect$inet(r4, &(0x7f00000006c0)={0x2, 0x4e24, @empty}, 0x10) r5 = openat$dir(0xffffffffffffff9c, &(0x7f00000000c0)='./file0\x00', 0x181e42, 0x0) fallocate(r5, 0x0, 0x0, 0x85b8) sendfile(r4, r5, 0x0, 0x8ba0) getsockopt$inet_tcp_TCP_ZEROCOPY_RECEIVE(r4, 0x6, 0x23, &(0x7f00000001c0)={&(0x7f0000ffb000/0x3000)=nil, 0x3000, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, &(0x7f0000000440)=0x40) r6 = openat$dir(0xffffffffffffff9c, &(0x7f00000000c0)='./file0\x00', 0x181e42, 0x0) Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Link: https://lore.kernel.org/netdev/5106a58e-04da-372a-b836-9d3d0bd2507b@huawei.c... Reported-and-bisected-by: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: linux-mm@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-fsdevel@vger.kernel.org Conflicts: net/ipv4/tcp.c Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> --- net/ipv4/tcp.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index dcbc5ec00da8..bb74fc0aa2d2 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1917,6 +1917,8 @@ static int tcp_zerocopy_receive(struct sock *sk, ret = 0; curr_addr = address; while (length + PAGE_SIZE <= zc->length) { + struct page *page; + if (zc->recv_skip_hint < PAGE_SIZE) { u32 offset_frag; @@ -1944,7 +1946,10 @@ static int tcp_zerocopy_receive(struct sock *sk, if (!frags || offset_frag) break; } - if (skb_frag_size(frags) != PAGE_SIZE || skb_frag_off(frags)) { + + page = skb_frag_page(frags); + if (skb_frag_size(frags) != PAGE_SIZE || skb_frag_off(frags) || + PageCompound(page) || page->mapping) { int remaining = zc->recv_skip_hint; while (remaining && (skb_frag_size(frags) != PAGE_SIZE || @@ -1955,7 +1960,7 @@ static int tcp_zerocopy_receive(struct sock *sk, zc->recv_skip_hint -= remaining; break; } - pages[pg_idx] = skb_frag_page(frags); + pages[pg_idx] = page; pg_idx++; length += PAGE_SIZE; zc->recv_skip_hint -= PAGE_SIZE; -- 2.34.1