[PATCH kernel-4.19 2/3] tcp_comp: Add dpkt to save decompressed skb

From: Wang Yufen wangyufen@huawei.com

hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I48H9Z?from=project-issue CVE: NA

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In order to separate the compressed data and decompressed data, this patch adds dpkt to tcp_comp_context_rx, dpkt is used to save decompressed skb.

Signed-off-by: Wang Yufen wangyufen@huawei.com Reviewed-by: Wei Yongjun weiyongjun1@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/ipv4/tcp_comp.c | 94 ++++++++++++++++++++++++++++++--------------- 1 file changed, 64 insertions(+), 30 deletions(-)

diff --git a/net/ipv4/tcp_comp.c b/net/ipv4/tcp_comp.c index de5f735c5ce61..c25600bcb4434 100644 --- a/net/ipv4/tcp_comp.c +++ b/net/ipv4/tcp_comp.c @@ -51,7 +51,7 @@ struct tcp_comp_context_rx { struct strparser strp; void (*saved_data_ready)(struct sock *sk); struct sk_buff *pkt; - bool decompressed; + struct sk_buff *dpkt; };

struct tcp_comp_context { @@ -534,6 +534,24 @@ static bool comp_advance_skb(struct sock *sk, struct sk_buff *skb, return true; }

+static bool comp_advance_dskb(struct sock *sk, struct sk_buff *skb, + unsigned int len) +{ + struct tcp_comp_context *ctx = comp_get_ctx(sk); + struct strp_msg *rxm = strp_msg(skb); + + if (len < rxm->full_len) { + rxm->offset += len; + rxm->full_len -= len; + return false; + } + + /* Finished with message */ + ctx->rx.dpkt = NULL; + kfree_skb(skb); + return true; +} + static int tcp_comp_rx_context_init(struct tcp_comp_context *ctx) { int dsize; @@ -590,13 +608,14 @@ static void *tcp_comp_get_rx_stream(struct sock *sk) return ctx->rx.plaintext_data; }

-static int tcp_comp_decompress(struct sock *sk, struct sk_buff *skb) +static int tcp_comp_decompress(struct sock *sk, struct sk_buff *skb, int flags) { struct tcp_comp_context *ctx = comp_get_ctx(sk); struct strp_msg *rxm = strp_msg(skb); const int plen = skb->len; ZSTD_outBuffer outbuf; ZSTD_inBuffer inbuf; + struct sk_buff *nskb; int len; void *to;

@@ -610,6 +629,10 @@ static int tcp_comp_decompress(struct sock *sk, struct sk_buff *skb) if (plen + ctx->rx.data_offset > TCP_COMP_MAX_CSIZE) return -ENOMEM;

+ nskb = skb_copy(skb, GFP_KERNEL); + if (!nskb) + return -ENOMEM; + if (ctx->rx.data_offset) memcpy(ctx->rx.compressed_data, ctx->rx.remaining_data, ctx->rx.data_offset); @@ -631,34 +654,38 @@ static int tcp_comp_decompress(struct sock *sk, struct sk_buff *skb)

to = outbuf.dst; ret = ZSTD_decompressStream(ctx->rx.dstream, &outbuf, &inbuf); - if (ZSTD_isError(ret)) + if (ZSTD_isError(ret)) { + kfree_skb(nskb); return -EIO; + }

len = outbuf.pos - plen; - if (len > skb_tailroom(skb)) - len = skb_tailroom(skb); + if (len > skb_tailroom(nskb)) + len = skb_tailroom(nskb);

- __skb_put(skb, len); - rxm->full_len += (len + rxm->offset); - rxm->offset = 0; + __skb_put(nskb, len);

len += plen; - skb_copy_to_linear_data(skb, to, len); + skb_copy_to_linear_data(nskb, to, len);

while ((to += len, outbuf.pos -= len) > 0) { struct page *pages; skb_frag_t *frag;

- if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) + if (WARN_ON(skb_shinfo(nskb)->nr_frags >= MAX_SKB_FRAGS)) { + kfree_skb(nskb); return -EMSGSIZE; + }

- frag = skb_shinfo(skb)->frags + - skb_shinfo(skb)->nr_frags; + frag = skb_shinfo(nskb)->frags + + skb_shinfo(nskb)->nr_frags; pages = alloc_pages(__GFP_NOWARN | GFP_KERNEL | __GFP_COMP, TCP_COMP_ALLOC_ORDER);

- if (!pages) + if (!pages) { + kfree_skb(nskb); return -ENOMEM; + }

__skb_frag_set_page(frag, pages); len = PAGE_SIZE << TCP_COMP_ALLOC_ORDER; @@ -669,11 +696,10 @@ static int tcp_comp_decompress(struct sock *sk, struct sk_buff *skb) skb_frag_size_set(frag, len); memcpy(skb_frag_address(frag), to, len);

- skb->truesize += len; - skb->data_len += len; - skb->len += len; - rxm->full_len += len; - skb_shinfo(skb)->nr_frags++; + nskb->truesize += len; + nskb->data_len += len; + nskb->len += len; + skb_shinfo(nskb)->nr_frags++; }

if (ret == 0) @@ -689,6 +715,13 @@ static int tcp_comp_decompress(struct sock *sk, struct sk_buff *skb) break; } } + + ctx->rx.dpkt = nskb; + rxm = strp_msg(nskb); + rxm->full_len = nskb->len; + rxm->offset = 0; + comp_advance_skb(sk, skb, plen - rxm->offset); + return 0; }

@@ -715,21 +748,19 @@ static int tcp_comp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, do { int chunk = 0;

- skb = comp_wait_data(sk, flags, timeo, &err); - if (!skb) - goto recv_end; + if (!ctx->rx.dpkt) { + skb = comp_wait_data(sk, flags, timeo, &err); + if (!skb) + goto recv_end;

- if (!ctx->rx.decompressed) { - err = tcp_comp_decompress(sk, skb); + err = tcp_comp_decompress(sk, skb, flags); if (err < 0) { goto recv_end; } - ctx->rx.decompressed = true; } + skb = ctx->rx.dpkt; rxm = strp_msg(skb); - chunk = min_t(unsigned int, rxm->full_len, len); - err = skb_copy_datagram_msg(skb, rxm->offset, msg, chunk); if (err < 0) @@ -738,11 +769,11 @@ static int tcp_comp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, copied += chunk; len -= chunk; if (likely(!(flags & MSG_PEEK))) - comp_advance_skb(sk, skb, chunk); + comp_advance_dskb(sk, skb, chunk); else break;

- if (copied >= target && !ctx->rx.pkt) + if (copied >= target && !ctx->rx.dpkt) break; } while (len > 0);

@@ -758,7 +789,7 @@ bool comp_stream_read(const struct sock *sk) if (!ctx) return false;

- if (ctx->rx.pkt) + if (ctx->rx.pkt || ctx->rx.dpkt) return true;

return false; @@ -775,7 +806,6 @@ static void comp_queue(struct strparser *strp, struct sk_buff *skb) { struct tcp_comp_context *ctx = comp_get_ctx(strp->sk);

- ctx->rx.decompressed = false; ctx->rx.pkt = skb; strp_pause(strp); ctx->rx.saved_data_ready(strp->sk); @@ -923,6 +953,10 @@ void tcp_cleanup_compression(struct sock *sk) kfree_skb(ctx->rx.pkt); ctx->rx.pkt = NULL; } + if (ctx->rx.dpkt) { + kfree_skb(ctx->rx.dpkt); + ctx->rx.dpkt = NULL; + } strp_stop(&ctx->rx.strp);

rcu_assign_pointer(icsk->icsk_ulp_data, NULL);