114 changes: 114 additions & 0 deletions clang/test/Analysis/vfork.c
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// RUN: %clang_cc1 -analyze -analyzer-checker=core,security.insecureAPI.vfork,unix.Vfork -verify %s
// RUN: %clang_cc1 -analyze -analyzer-checker=core,security.insecureAPI.vfork,unix.Vfork -verify -x c++ %s

#include "Inputs/system-header-simulator.h"

void foo();

// Ensure that child process is properly checked.
int f1(int x) {
pid_t pid = vfork(); // expected-warning{{Call to function 'vfork' is insecure}}
if (pid != 0)
return 0;

switch (x) {
case 0:
// Ensure that modifying pid is ok.
pid = 1; // no-warning
// Ensure that calling whitelisted routines is ok.
execl("", "", 0); // no-warning
_exit(1); // no-warning
break;
case 1:
// Ensure that writing variables is prohibited.
x = 0; // expected-warning{{This assignment is prohibited after a successful vfork}}
break;
case 2:
// Ensure that calling functions is prohibited.
foo(); // expected-warning{{This function call is prohibited after a successful vfork}}
break;
default:
// Ensure that returning from function is prohibited.
return 0; // expected-warning{{Return is prohibited after a successful vfork; call _exit() instead}}
}

while(1);
}

// Same as previous but without explicit pid variable.
int f2(int x) {
pid_t pid = vfork(); // expected-warning{{Call to function 'vfork' is insecure}}

switch (x) {
case 0:
// Ensure that writing pid is ok.
pid = 1; // no-warning
// Ensure that calling whitelisted routines is ok.
execl("", "", 0); // no-warning
_exit(1); // no-warning
break;
case 1:
// Ensure that writing variables is prohibited.
x = 0; // expected-warning{{This assignment is prohibited after a successful vfork}}
break;
case 2:
// Ensure that calling functions is prohibited.
foo(); // expected-warning{{This function call is prohibited after a successful vfork}}
break;
default:
// Ensure that returning from function is prohibited.
return 0; // expected-warning{{Return is prohibited after a successful vfork; call _exit() instead}}
}

while(1);
}

// Ensure that parent process isn't restricted.
int f3(int x) {
if (vfork() == 0) // expected-warning{{Call to function 'vfork' is insecure}}
_exit(1);
x = 0; // no-warning
foo(); // no-warning
return 0;
} // no-warning

// Unbound pids are special so test them separately.
void f4(int x) {
switch (x) {
case 0:
vfork(); // expected-warning{{Call to function 'vfork' is insecure}}
x = 0; // expected-warning{{This assignment is prohibited after a successful vfork}}
break;

case 1:
{
char args[2];
switch (vfork()) { // expected-warning{{Call to function 'vfork' is insecure}}
case 0:
args[0] = 0; // expected-warning{{This assignment is prohibited after a successful vfork}}
exit(1);
}
break;
}

case 2:
{
pid_t pid;
if ((pid = vfork()) == 0) // expected-warning{{Call to function 'vfork' is insecure}}
while(1); // no-warning
break;
}
}
while(1);
} //no-warning


void f5() {
// See "libxtables: move some code to avoid cautions in vfork man page"
// (http://lists.netfilter.org/pipermail/netfilter-buglog/2014-October/003280.html).
if (vfork() == 0) { // expected-warning{{Call to function 'vfork' is insecure}}
execl("prog", "arg1", 0); // no-warning
exit(1); // expected-warning{{This function call is prohibited after a successful vfork}}
}
}