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authorXufeng Zhang <xufeng.zhang@windriver.com>2011-06-21 10:43:40 +0000
committerAndi Kleen <ak@linux.intel.com>2011-08-01 13:54:59 -0700
commitcc51d661483c95a61b5385e70e56af019059bde8 (patch)
tree55dc62eeb60cbc3f9c48f03917f1e2ae31974325 /net
parentf5e8deec38218b6c2c20b546dd7727640d68d8f5 (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> Signed-off-by: Andi Kleen <ak@linux.intel.com>
Diffstat (limited to 'net')
-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 f0fbbba1d20..43536dc8b95 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1206,6 +1206,9 @@ 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 e49cf67506e..af1a88502d0 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -447,6 +447,9 @@ csum_copy_err:
if (noblock)
return -EAGAIN;
+
+ /* starting over for a new packet */
+ msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}