190449a5d2
Fix some false negatives of StackAddrEscapeChecker:
- Output parameters
```
void top(int **out) {
int local = 42;
*out = &local; // Noncompliant
}
```
- Indirect global pointers
```
int **global;
void top() {
int local = 42;
*global = &local; // Noncompliant
}
```
Note that now StackAddrEscapeChecker produces a diagnostic if a function
with an output parameter is analyzed as top-level or as a callee. I took
special care to make sure the reports point to the same primary location
and, in many cases, feature the same primary message. That is the
motivation to modify Core/BugReporter.cpp and Core/ExplodedGraph.cpp
To avoid false positive reports when a global indirect pointer is
assigned a local address, invalidated, and then reset, I rely on the
fact that the invalidation symbol will be a DerivedSymbol of a
ConjuredSymbol that refers to the same memory region.
The checker still has a false negative for non-trivial escaping via a
returned value. It requires a more sophisticated traversal akin to
scanReachableSymbols, which out of the scope of this change.
CPP-4734
---------
This is the last of the 3 stacked PRs, it must not be merged before
https://github.com/llvm/llvm-project/pull/105652 and
https://github.com/llvm/llvm-project/pull/105653
59 lines
2.2 KiB
C
59 lines
2.2 KiB
C
// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.Malloc -verify -std=c99 -Dbool=_Bool -Wno-bool-conversion %s
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// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.Malloc -verify -x c++ -Wno-bool-conversion %s
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typedef __INTPTR_TYPE__ intptr_t;
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char const *p;
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void f0(void) {
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char const str[] = "This will change";
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p = str;
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} // expected-warning@-1{{Address of stack memory associated with local variable 'str' is still referred to by the global variable 'p' upon returning to the caller. This will be a dangling reference}}
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void f1(void) {
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char const str[] = "This will change";
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p = str;
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p = 0; // no-warning
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}
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void f2(void) {
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p = (const char *) __builtin_alloca(12);
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} // expected-warning@-1{{Address of stack memory allocated by call to alloca() on line 19 is still referred to by the global variable 'p' upon returning to the caller. This will be a dangling reference}}
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// PR 7383 - previously the stack address checker would crash on this example
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// because it would attempt to do a direct load from 'pr7383_list'.
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static int pr7383(__const char *__)
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{
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return 0;
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}
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extern __const char *__const pr7383_list[];
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// Test that we catch multiple returns via globals when analyzing a function.
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void test_multi_return(void) {
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static int *a, *b;
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int x;
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a = &x;
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b = &x;
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} // expected-warning@-1{{Address of stack memory associated with local variable 'x' is still referred to by the static variable 'a' upon returning}} expected-warning@-1{{Address of stack memory associated with local variable 'x' is still referred to by the static variable 'b' upon returning}}
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intptr_t returnAsNonLoc(void) {
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int x;
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return (intptr_t)&x; // expected-warning{{Address of stack memory associated with local variable 'x' returned to caller}} expected-warning{{address of stack memory associated with local variable 'x' returned}}
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}
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bool returnAsBool(void) {
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int x;
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return &x; // no-warning
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}
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void assignAsNonLoc(void) {
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extern intptr_t ip;
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int x;
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ip = (intptr_t)&x;
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} // expected-warning@-1{{Address of stack memory associated with local variable 'x' is still referred to by the global variable 'ip' upon returning}}
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void assignAsBool(void) {
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extern bool b;
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int x;
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b = &x;
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} // no-warning
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