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mptcp: Fix out of bounds when parsing TCP options

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[ Upstream commit 07718be265 ]

The TCP option parser in mptcp (mptcp_get_options) could read one byte
out of bounds. When the length is 1, the execution flow gets into the
loop, reads one byte of the opcode, and if the opcode is neither
TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the
length of 1.

This fix is inspired by commit 9609dad263 ("ipv4: tcp_input: fix stack
out of bounds when parsing TCP options.").

Cc: Young Xiao <92siuyang@gmail.com>
Fixes: cec37a6e41 ("mptcp: Handle MP_CAPABLE options for outgoing connections")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Maxim Mikityanskiy 2021-06-10 19:40:30 +03:00 • committed by Greg Kroah-Hartman
commit 73eeba71dc
1 changed files with 2 additions and 0 deletions
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2
net/mptcp/options.c
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@ -314,6 +314,8 @@ void mptcp_get_options(const struct sk_buff *skb,
length--;
continue;
default:
if (length < 2)
return;
opsize = *ptr++;
if (opsize < 2) /* "silly options" */
return;