mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
synced 2024-10-01 01:35:54 -04:00
95 lines
2.9 KiB
Diff
95 lines
2.9 KiB
Diff
From 197c949e7798fbf28cfadc69d9ca0c2abbf93191 Mon Sep 17 00:00:00 2001
|
|
From: Eric Dumazet <edumazet@google.com>
|
|
Date: Wed, 30 Dec 2015 08:51:12 -0500
|
|
Subject: udp: properly support MSG_PEEK with truncated buffers
|
|
|
|
Backport of this upstream commit into stable kernels :
|
|
89c22d8c3b27 ("net: Fix skb csum races when peeking")
|
|
exposed a bug in udp stack vs MSG_PEEK support, when user provides
|
|
a buffer smaller than skb payload.
|
|
|
|
In this case,
|
|
skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr),
|
|
msg->msg_iov);
|
|
returns -EFAULT.
|
|
|
|
This bug does not happen in upstream kernels since Al Viro did a great
|
|
job to replace this into :
|
|
skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr), msg);
|
|
This variant is safe vs short buffers.
|
|
|
|
For the time being, instead reverting Herbert Xu patch and add back
|
|
skb->ip_summed invalid changes, simply store the result of
|
|
udp_lib_checksum_complete() so that we avoid computing the checksum a
|
|
second time, and avoid the problematic
|
|
skb_copy_and_csum_datagram_iovec() call.
|
|
|
|
This patch can be applied on recent kernels as it avoids a double
|
|
checksumming, then backported to stable kernels as a bug fix.
|
|
|
|
Signed-off-by: Eric Dumazet <edumazet@google.com>
|
|
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
|
|
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
---
|
|
net/ipv4/udp.c | 6 ++++--
|
|
net/ipv6/udp.c | 6 ++++--
|
|
2 files changed, 8 insertions(+), 4 deletions(-)
|
|
|
|
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
|
|
index 8841e98..ac14ae4 100644
|
|
--- a/net/ipv4/udp.c
|
|
+++ b/net/ipv4/udp.c
|
|
@@ -1271,6 +1271,7 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
|
|
int peeked, off = 0;
|
|
int err;
|
|
int is_udplite = IS_UDPLITE(sk);
|
|
+ bool checksum_valid = false;
|
|
bool slow;
|
|
|
|
if (flags & MSG_ERRQUEUE)
|
|
@@ -1296,11 +1297,12 @@ try_again:
|
|
*/
|
|
|
|
if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
|
|
- if (udp_lib_checksum_complete(skb))
|
|
+ checksum_valid = !udp_lib_checksum_complete(skb);
|
|
+ if (!checksum_valid)
|
|
goto csum_copy_err;
|
|
}
|
|
|
|
- if (skb_csum_unnecessary(skb))
|
|
+ if (checksum_valid || skb_csum_unnecessary(skb))
|
|
err = skb_copy_datagram_msg(skb, sizeof(struct udphdr),
|
|
msg, copied);
|
|
else {
|
|
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
|
|
index 9da3287..00775ee 100644
|
|
--- a/net/ipv6/udp.c
|
|
+++ b/net/ipv6/udp.c
|
|
@@ -402,6 +402,7 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
|
|
int peeked, off = 0;
|
|
int err;
|
|
int is_udplite = IS_UDPLITE(sk);
|
|
+ bool checksum_valid = false;
|
|
int is_udp4;
|
|
bool slow;
|
|
|
|
@@ -433,11 +434,12 @@ try_again:
|
|
*/
|
|
|
|
if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
|
|
- if (udp_lib_checksum_complete(skb))
|
|
+ checksum_valid = !udp_lib_checksum_complete(skb);
|
|
+ if (!checksum_valid)
|
|
goto csum_copy_err;
|
|
}
|
|
|
|
- if (skb_csum_unnecessary(skb))
|
|
+ if (checksum_valid || skb_csum_unnecessary(skb))
|
|
err = skb_copy_datagram_msg(skb, sizeof(struct udphdr),
|
|
msg, copied);
|
|
else {
|
|
--
|
|
cgit v1.1
|
|
|