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authorXufeng Zhang <xufeng.zhang@windriver.com>2011-06-21 10:43:40 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2011-07-13 05:29:27 +0200
commit453d61c441601d3f4ed9df7cfade4c5c35e98526 (patch)
treee460273a126f81539a38931125ed6b8afc1bb33e
parentac7573b57eab6975cf4d15bb79f9733639b437a3 (diff)
udp/recvmsg: Clear MSG_TRUNC flag when starting over for a new packet
[ Upstream commit 9cfaa8def1c795a512bc04f2aec333b03724ca2e ] Consider this scenario: When the size of the first received udp packet is bigger than the receive buffer, MSG_TRUNC bit is set in msg->msg_flags. However, if checksum error happens and this is a blocking socket, it will goto try_again loop to receive the next packet. But if the size of the next udp packet is smaller than receive buffer, MSG_TRUNC flag should not be set, but because MSG_TRUNC bit is not cleared in msg->msg_flags before receive the next packet, MSG_TRUNC is still set, which is wrong. Fix this problem by clearing MSG_TRUNC flag when starting over for a new packet. Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/ipv4/udp.c3
-rw-r--r--net/ipv6/udp.c3
2 files changed, 6 insertions, 0 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 31db78ca7469..0ac88332d56a 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1011,6 +1011,9 @@ csum_copy_err:
if (noblock)
return -EAGAIN;
+
+ /* starting over for a new packet */
+ msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 852a07faf64a..ca520d4d9069 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -306,6 +306,9 @@ csum_copy_err:
if (noblock)
return -EAGAIN;
+
+ /* starting over for a new packet */
+ msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}