...
| Code Block | ||||
|---|---|---|---|---|
| ||||
jmp_buf buf;
void f(void) {
int i = 0;
if (setjmp(buf) != 0) {
printf("%i\n", i);
/* ... */
}
i = 2;
g();
}
void g(void) {
/* ... */
longjmp(buf, 1);
}
|
Calling f() will print 2 if you compile with -O0, but will print 3 if you compile with -O2.
Compliant Solution
If an object local to the function that invoked setjmp() needs to be accessed after longjmp() returns control to the function, the object should be volatile-qualified:
| Code Block | ||||
|---|---|---|---|---|
| ||||
jmp_buf buf;
void f(void) {
volatile int i = 0;
if (setjmp(buf) != 0) {
printf("%i\n", i);
/* ... */
}
i = 2;
g();
}
void g(void) {
/* ... */
longjmp(buf, 1);
}
|
This will now correctly print 2 regardless of optimization level.
Risk Assessment
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
MSC22-C | Low | Probable | Medium | P4 | L3 |
...