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authorEric Dumazet <edumazet@google.com>2024-01-25 10:33:17 +0000
committerDavid S. Miller <davem@davemloft.net>2024-01-29 12:07:35 +0000
commit577e4432f3ac810049cb7e6b71f4d96ec7c6e894 (patch)
treeda07ae3670a824840d1d312878ce1e532adfb1b4 /net
parentbfb007aebe6bff451f7f3a4be19f4f286d0d5d9c (diff)
tcp: add sanity checks to rx zerocopy
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.com/T/ 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>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a1c6de385cce..7e2481b9eae1 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1786,7 +1786,17 @@ static skb_frag_t *skb_advance_to_frag(struct sk_buff *skb, u32 offset_skb,
static bool can_map_frag(const skb_frag_t *frag)
{
- return skb_frag_size(frag) == PAGE_SIZE && !skb_frag_off(frag);
+ struct page *page;
+
+ if (skb_frag_size(frag) != PAGE_SIZE || skb_frag_off(frag))
+ return false;
+
+ page = skb_frag_page(frag);
+
+ if (PageCompound(page) || page->mapping)
+ return false;
+
+ return true;
}
static int find_next_mappable_frag(const skb_frag_t *frag,