From: Eric Dumazet edumazet@google.com

mainline inclusion from mainline-v6.8-rc3 commit 577e4432f3ac810049cb7e6b71f4d96ec7c6e894 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I99JO6 CVE: CVE-2024-26640

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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 Signed-off-by: David S. Miller davem@davemloft.net Conflicts: net/ipv4/tcp.c Signed-off-by: Ziyang Xuan william.xuanziyang@huawei.com --- net/ipv4/tcp.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index fb2b55894b8dc..4416d1c24dbbe 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1810,6 +1810,8 @@ static int tcp_zerocopy_receive(struct sock *sk, zc->recv_skip_hint = 0; ret = 0; while (length + PAGE_SIZE <= zc->length) { + struct page *page; + if (zc->recv_skip_hint < PAGE_SIZE) { if (skb) { skb = skb->next; @@ -1830,7 +1832,9 @@ static int tcp_zerocopy_receive(struct sock *sk, frags++; } } - if (frags->size != PAGE_SIZE || frags->page_offset) + page = skb_frag_page(frags); + if (frags->size != PAGE_SIZE || frags->page_offset || + PageCompound(page) || page->mapping) break; ret = vm_insert_page(vma, address + length, skb_frag_page(frags));