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// PR11234: __get_argv can overflow its return buffer
// __get_argv has a signature like this:
// struct function___get_argv_locals {
// int64_t a;
// int64_t first;
// string_t __retvalue;
// } function___get_argv;
//
// These functions are meant to have an overlap such that we can tell if
// __get_argv overran its __retvalue.
//
// int64_t x;
// int64_t y;
// string_t z;
// string_t __retvalue;
//
// NB: __retvalue[0] always gets cleared on call, but the rest should be
// untouched, so we can use it as a sentinal.
function clear:string(x:long, y:long, z:string) %{
memset(THIS->__retvalue, 0, MAXSTRINGLEN);
%}
function check:string(x:long, y:long, z:string) %{
int i, bad = 0;
for (i=1; i<MAXSTRINGLEN; ++i)
if (THIS->__retvalue[i])
++bad;
if (bad)
snprintf(THIS->__retvalue, MAXSTRINGLEN, "%d non-zero bytes", bad);
else
strlcpy(THIS->__retvalue, "ok", MAXSTRINGLEN);
%}
global result = "untested"
probe syscall.execve {
if (pid() != target())
next
clear(0, 0, "")
foo = __get_argv($argv, 0)
result = check(0, 0, "")
// ensure that foo isn't optimized away
if (foo == "foo")
next
}
probe begin {
println("systemtap starting probe")
}
probe end {
println("systemtap ending probe")
if (result == "ok")
println("systemtap test success")
else
println("systemtap test failure: ", result)
}
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