SUNRPC: Fix a potential buffer overflow in 'svc_print_xprts()'
'maxlen' is the total size of the destination buffer. There is only one caller and this value is 256. When we compute the size already used and what we would like to add in the buffer, the trailling NULL character is not taken into account. However, this trailling character will be added by the 'strcat' once we have checked that we have enough place. So, there is a off-by-one issue and 1 byte of the stack could be erroneously overwridden. Take into account the trailling NULL, when checking if there is enough place in the destination buffer. While at it, also replace a 'sprintf' by a safer 'snprintf', check for output truncation and avoid a superfluous 'strlen'. Fixes: dc9a16e4 ("svc: Add /proc/sys/sunrpc/transport files") Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr> [ cel: very minor fix to documenting comment Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
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