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Merged
merged 5 commits into from
Apr 15, 2020
Merged

C++ Improvements to TaintedAllocationSize.ql #3241

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febbbc4
C++: Additional test cases.
geoffw0 Apr 9, 2020
a7979fd
C++: Base results purely on allocations now, not multiplications by a…
geoffw0 Apr 9, 2020
ba3a8d0
C++: Improve naming and QLDoc.
geoffw0 Apr 9, 2020
92187d9
C++: Change note.
geoffw0 Apr 9, 2020
2aa64db
Merge remote-tracking branch 'upstream/rc/1.24' into alloc-size2
geoffw0 Apr 15, 2020
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1 change: 1 addition & 0 deletions change-notes/1.24/analysis-cpp.md
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ The following changes in version 1.24 affect C/C++ analysis in all applications.
| Hard-coded Japanese era start date (`cpp/japanese-era/exact-era-date`) | | This query is no longer run on LGTM. |
| No space for zero terminator (`cpp/no-space-for-terminator`) | Fewer false positive results | This query has been modified to be more conservative when identifying which pointers point to null-terminated strings. This approach produces fewer, more accurate results. |
| Overflow in uncontrolled allocation size (`cpp/uncontrolled-allocation-size`) | Fewer false positive results | Cases where the tainted allocation size is range checked are now more reliably excluded. |
| Overflow in uncontrolled allocation size (`cpp/uncontrolled-allocation-size`) | Fewer false positive results | The query now produces fewer, more accurate results. |
| Overloaded assignment does not return 'this' (`cpp/assignment-does-not-return-this`) | Fewer false positive results | This query no longer reports incorrect results in template classes. |
| Unsafe array for days of the year (`cpp/leap-year/unsafe-array-for-days-of-the-year`) | | This query is no longer run on LGTM. |
| Unsigned comparison to zero (`cpp/unsigned-comparison-zero`) | More correct results | This query now also looks for comparisons of the form `0 <= x`. |
Expand Down
26 changes: 13 additions & 13 deletions cpp/ql/src/Security/CWE/CWE-190/TaintedAllocationSize.ql
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Expand Up @@ -15,31 +15,31 @@ import cpp
import semmle.code.cpp.security.TaintTracking
import TaintedWithPath

predicate taintedChild(Expr e, Expr tainted) {
(
isAllocationExpr(e)
or
any(MulExpr me | me.getAChild() instanceof SizeofOperator) = e
) and
tainted = e.getAChild() and
/**
* Holds if `alloc` is an allocation, and `tainted` is a child of it that is a
* taint sink.
*/
predicate allocSink(Expr alloc, Expr tainted) {
isAllocationExpr(alloc) and
tainted = alloc.getAChild() and
tainted.getUnspecifiedType() instanceof IntegralType
}

class TaintedAllocationSizeConfiguration extends TaintTrackingConfiguration {
override predicate isSink(Element tainted) { taintedChild(_, tainted) }
override predicate isSink(Element tainted) { allocSink(_, tainted) }
}

predicate taintedAllocSize(
Expr e, Expr source, PathNode sourceNode, PathNode sinkNode, string taintCause
Expr source, Expr alloc, PathNode sourceNode, PathNode sinkNode, string taintCause
) {
isUserInput(source, taintCause) and
exists(Expr tainted |
taintedChild(e, tainted) and
allocSink(alloc, tainted) and
taintedWithPath(source, tainted, sourceNode, sinkNode)
)
}

from Expr e, Expr source, PathNode sourceNode, PathNode sinkNode, string taintCause
where taintedAllocSize(e, source, sourceNode, sinkNode, taintCause)
select e, sourceNode, sinkNode, "This allocation size is derived from $@ and might overflow",
from Expr source, Expr alloc, PathNode sourceNode, PathNode sinkNode, string taintCause
where taintedAllocSize(source, alloc, sourceNode, sinkNode, taintCause)
select alloc, sourceNode, sinkNode, "This allocation size is derived from $@ and might overflow",
source, "user input (" + taintCause + ")"
107 changes: 47 additions & 60 deletions ...ry-tests/Security/CWE/CWE-190/semmle/TaintedAllocationSize/TaintedAllocationSize.expected
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Expand Up @@ -5,12 +5,6 @@ edges
| test.cpp:39:21:39:24 | argv | test.cpp:42:38:42:44 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:42:38:42:44 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:42:38:42:44 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:44 | (unsigned long)... |
| test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:44 | (unsigned long)... |
| test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:44 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:44 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:44 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:44 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:63 | ... * ... |
| test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:63 | ... * ... |
| test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:63 | ... * ... |
Expand All @@ -33,42 +27,38 @@ edges
| test.cpp:39:21:39:24 | argv | test.cpp:52:35:52:60 | ... * ... |
| test.cpp:39:21:39:24 | argv | test.cpp:52:35:52:60 | ... * ... |
| test.cpp:39:21:39:24 | argv | test.cpp:52:35:52:60 | ... * ... |
| test.cpp:39:21:39:24 | argv | test.cpp:52:54:52:60 | (unsigned long)... |
| test.cpp:39:21:39:24 | argv | test.cpp:52:54:52:60 | (unsigned long)... |
| test.cpp:39:21:39:24 | argv | test.cpp:52:54:52:60 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:52:54:52:60 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:52:54:52:60 | tainted |
| test.cpp:39:21:39:24 | argv | test.cpp:52:54:52:60 | tainted |
| test.cpp:123:18:123:23 | call to getenv | test.cpp:127:24:127:27 | (unsigned long)... |
| test.cpp:123:18:123:23 | call to getenv | test.cpp:127:24:127:27 | size |
| test.cpp:123:18:123:23 | call to getenv | test.cpp:127:24:127:27 | size |
| test.cpp:123:18:123:23 | call to getenv | test.cpp:127:24:127:41 | ... * ... |
| test.cpp:123:18:123:23 | call to getenv | test.cpp:127:24:127:41 | ... * ... |
| test.cpp:123:18:123:31 | (const char *)... | test.cpp:127:24:127:27 | (unsigned long)... |
| test.cpp:123:18:123:31 | (const char *)... | test.cpp:127:24:127:27 | size |
| test.cpp:123:18:123:31 | (const char *)... | test.cpp:127:24:127:27 | size |
| test.cpp:123:18:123:31 | (const char *)... | test.cpp:127:24:127:41 | ... * ... |
| test.cpp:123:18:123:31 | (const char *)... | test.cpp:127:24:127:41 | ... * ... |
| test.cpp:132:19:132:24 | call to getenv | test.cpp:134:10:134:13 | (unsigned long)... |
| test.cpp:132:19:132:24 | call to getenv | test.cpp:134:10:134:13 | size |
| test.cpp:132:19:132:24 | call to getenv | test.cpp:134:10:134:13 | size |
| test.cpp:132:19:132:24 | call to getenv | test.cpp:134:10:134:27 | ... * ... |
| test.cpp:132:19:132:24 | call to getenv | test.cpp:134:10:134:27 | ... * ... |
| test.cpp:132:19:132:32 | (const char *)... | test.cpp:134:10:134:13 | (unsigned long)... |
| test.cpp:132:19:132:32 | (const char *)... | test.cpp:134:10:134:13 | size |
| test.cpp:132:19:132:32 | (const char *)... | test.cpp:134:10:134:13 | size |
| test.cpp:132:19:132:32 | (const char *)... | test.cpp:134:10:134:27 | ... * ... |
| test.cpp:132:19:132:32 | (const char *)... | test.cpp:134:10:134:27 | ... * ... |
| test.cpp:138:19:138:24 | call to getenv | test.cpp:142:11:142:14 | (unsigned long)... |
| test.cpp:138:19:138:24 | call to getenv | test.cpp:142:11:142:14 | size |
| test.cpp:138:19:138:24 | call to getenv | test.cpp:142:11:142:14 | size |
| test.cpp:138:19:138:24 | call to getenv | test.cpp:142:11:142:28 | ... * ... |
| test.cpp:138:19:138:24 | call to getenv | test.cpp:142:11:142:28 | ... * ... |
| test.cpp:138:19:138:32 | (const char *)... | test.cpp:142:11:142:14 | (unsigned long)... |
| test.cpp:138:19:138:32 | (const char *)... | test.cpp:142:11:142:14 | size |
| test.cpp:138:19:138:32 | (const char *)... | test.cpp:142:11:142:14 | size |
| test.cpp:138:19:138:32 | (const char *)... | test.cpp:142:11:142:28 | ... * ... |
| test.cpp:138:19:138:32 | (const char *)... | test.cpp:142:11:142:28 | ... * ... |
| test.cpp:201:9:201:42 | Store | test.cpp:231:9:231:24 | call to get_tainted_size |
| test.cpp:201:9:201:42 | Store | test.cpp:231:9:231:24 | call to get_tainted_size |
| test.cpp:201:14:201:19 | call to getenv | test.cpp:201:9:201:42 | Store |
| test.cpp:201:14:201:27 | (const char *)... | test.cpp:201:9:201:42 | Store |
| test.cpp:214:23:214:23 | s | test.cpp:215:21:215:21 | s |
| test.cpp:214:23:214:23 | s | test.cpp:215:21:215:21 | s |
| test.cpp:220:21:220:21 | s | test.cpp:221:21:221:21 | s |
| test.cpp:220:21:220:21 | s | test.cpp:221:21:221:21 | s |
| test.cpp:227:24:227:29 | call to getenv | test.cpp:229:9:229:18 | (size_t)... |
| test.cpp:227:24:227:29 | call to getenv | test.cpp:229:9:229:18 | local_size |
| test.cpp:227:24:227:29 | call to getenv | test.cpp:229:9:229:18 | local_size |
| test.cpp:227:24:227:29 | call to getenv | test.cpp:235:11:235:20 | (size_t)... |
| test.cpp:227:24:227:29 | call to getenv | test.cpp:237:10:237:19 | (size_t)... |
| test.cpp:227:24:227:37 | (const char *)... | test.cpp:229:9:229:18 | (size_t)... |
| test.cpp:227:24:227:37 | (const char *)... | test.cpp:229:9:229:18 | local_size |
| test.cpp:227:24:227:37 | (const char *)... | test.cpp:229:9:229:18 | local_size |
| test.cpp:227:24:227:37 | (const char *)... | test.cpp:235:11:235:20 | (size_t)... |
| test.cpp:227:24:227:37 | (const char *)... | test.cpp:237:10:237:19 | (size_t)... |
| test.cpp:235:11:235:20 | (size_t)... | test.cpp:214:23:214:23 | s |
| test.cpp:237:10:237:19 | (size_t)... | test.cpp:220:21:220:21 | s |
nodes
| test.cpp:39:21:39:24 | argv | semmle.label | argv |
| test.cpp:39:21:39:24 | argv | semmle.label | argv |
Expand All @@ -77,11 +67,6 @@ nodes
| test.cpp:42:38:42:44 | tainted | semmle.label | tainted |
| test.cpp:42:38:42:44 | tainted | semmle.label | tainted |
| test.cpp:42:38:42:44 | tainted | semmle.label | tainted |
| test.cpp:43:38:43:44 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:43:38:43:44 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:43:38:43:44 | tainted | semmle.label | tainted |
| test.cpp:43:38:43:44 | tainted | semmle.label | tainted |
| test.cpp:43:38:43:44 | tainted | semmle.label | tainted |
| test.cpp:43:38:43:63 | ... * ... | semmle.label | ... * ... |
| test.cpp:43:38:43:63 | ... * ... | semmle.label | ... * ... |
| test.cpp:43:38:43:63 | ... * ... | semmle.label | ... * ... |
Expand All @@ -99,53 +84,55 @@ nodes
| test.cpp:52:35:52:60 | ... * ... | semmle.label | ... * ... |
| test.cpp:52:35:52:60 | ... * ... | semmle.label | ... * ... |
| test.cpp:52:35:52:60 | ... * ... | semmle.label | ... * ... |
| test.cpp:52:54:52:60 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:52:54:52:60 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:52:54:52:60 | tainted | semmle.label | tainted |
| test.cpp:52:54:52:60 | tainted | semmle.label | tainted |
| test.cpp:52:54:52:60 | tainted | semmle.label | tainted |
| test.cpp:123:18:123:23 | call to getenv | semmle.label | call to getenv |
| test.cpp:123:18:123:31 | (const char *)... | semmle.label | (const char *)... |
| test.cpp:127:24:127:27 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:127:24:127:27 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:127:24:127:27 | size | semmle.label | size |
| test.cpp:127:24:127:27 | size | semmle.label | size |
| test.cpp:127:24:127:27 | size | semmle.label | size |
| test.cpp:127:24:127:41 | ... * ... | semmle.label | ... * ... |
| test.cpp:127:24:127:41 | ... * ... | semmle.label | ... * ... |
| test.cpp:127:24:127:41 | ... * ... | semmle.label | ... * ... |
| test.cpp:132:19:132:24 | call to getenv | semmle.label | call to getenv |
| test.cpp:132:19:132:32 | (const char *)... | semmle.label | (const char *)... |
| test.cpp:134:10:134:13 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:134:10:134:13 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:134:10:134:13 | size | semmle.label | size |
| test.cpp:134:10:134:13 | size | semmle.label | size |
| test.cpp:134:10:134:13 | size | semmle.label | size |
| test.cpp:134:10:134:27 | ... * ... | semmle.label | ... * ... |
| test.cpp:134:10:134:27 | ... * ... | semmle.label | ... * ... |
| test.cpp:134:10:134:27 | ... * ... | semmle.label | ... * ... |
| test.cpp:138:19:138:24 | call to getenv | semmle.label | call to getenv |
| test.cpp:138:19:138:32 | (const char *)... | semmle.label | (const char *)... |
| test.cpp:142:11:142:14 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:142:11:142:14 | (unsigned long)... | semmle.label | (unsigned long)... |
| test.cpp:142:11:142:14 | size | semmle.label | size |
| test.cpp:142:11:142:14 | size | semmle.label | size |
| test.cpp:142:11:142:14 | size | semmle.label | size |
| test.cpp:142:11:142:28 | ... * ... | semmle.label | ... * ... |
| test.cpp:142:11:142:28 | ... * ... | semmle.label | ... * ... |
| test.cpp:142:11:142:28 | ... * ... | semmle.label | ... * ... |
| test.cpp:201:9:201:42 | Store | semmle.label | Store |
| test.cpp:201:14:201:19 | call to getenv | semmle.label | call to getenv |
| test.cpp:201:14:201:27 | (const char *)... | semmle.label | (const char *)... |
| test.cpp:214:23:214:23 | s | semmle.label | s |
| test.cpp:215:21:215:21 | s | semmle.label | s |
| test.cpp:215:21:215:21 | s | semmle.label | s |
| test.cpp:215:21:215:21 | s | semmle.label | s |
| test.cpp:220:21:220:21 | s | semmle.label | s |
| test.cpp:221:21:221:21 | s | semmle.label | s |
| test.cpp:221:21:221:21 | s | semmle.label | s |
| test.cpp:221:21:221:21 | s | semmle.label | s |
| test.cpp:227:24:227:29 | call to getenv | semmle.label | call to getenv |
| test.cpp:227:24:227:37 | (const char *)... | semmle.label | (const char *)... |
| test.cpp:229:9:229:18 | (size_t)... | semmle.label | (size_t)... |
| test.cpp:229:9:229:18 | (size_t)... | semmle.label | (size_t)... |
| test.cpp:229:9:229:18 | local_size | semmle.label | local_size |
| test.cpp:229:9:229:18 | local_size | semmle.label | local_size |
| test.cpp:229:9:229:18 | local_size | semmle.label | local_size |
| test.cpp:231:9:231:24 | call to get_tainted_size | semmle.label | call to get_tainted_size |
| test.cpp:231:9:231:24 | call to get_tainted_size | semmle.label | call to get_tainted_size |
| test.cpp:231:9:231:24 | call to get_tainted_size | semmle.label | call to get_tainted_size |
| test.cpp:235:11:235:20 | (size_t)... | semmle.label | (size_t)... |
| test.cpp:237:10:237:19 | (size_t)... | semmle.label | (size_t)... |
#select
| test.cpp:42:31:42:36 | call to malloc | test.cpp:39:21:39:24 | argv | test.cpp:42:38:42:44 | tainted | This allocation size is derived from $@ and might overflow | test.cpp:39:21:39:24 | argv | user input (argv) |
| test.cpp:43:31:43:36 | call to malloc | test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:63 | ... * ... | This allocation size is derived from $@ and might overflow | test.cpp:39:21:39:24 | argv | user input (argv) |
| test.cpp:43:38:43:63 | ... * ... | test.cpp:39:21:39:24 | argv | test.cpp:43:38:43:44 | tainted | This allocation size is derived from $@ and might overflow | test.cpp:39:21:39:24 | argv | user input (argv) |
| test.cpp:45:31:45:36 | call to malloc | test.cpp:39:21:39:24 | argv | test.cpp:45:38:45:63 | ... + ... | This allocation size is derived from $@ and might overflow | test.cpp:39:21:39:24 | argv | user input (argv) |
| test.cpp:48:25:48:30 | call to malloc | test.cpp:39:21:39:24 | argv | test.cpp:48:32:48:35 | size | This allocation size is derived from $@ and might overflow | test.cpp:39:21:39:24 | argv | user input (argv) |
| test.cpp:49:17:49:30 | new[] | test.cpp:39:21:39:24 | argv | test.cpp:49:26:49:29 | size | This allocation size is derived from $@ and might overflow | test.cpp:39:21:39:24 | argv | user input (argv) |
| test.cpp:52:21:52:27 | call to realloc | test.cpp:39:21:39:24 | argv | test.cpp:52:35:52:60 | ... * ... | This allocation size is derived from $@ and might overflow | test.cpp:39:21:39:24 | argv | user input (argv) |
| test.cpp:52:35:52:60 | ... * ... | test.cpp:39:21:39:24 | argv | test.cpp:52:54:52:60 | tainted | This allocation size is derived from $@ and might overflow | test.cpp:39:21:39:24 | argv | user input (argv) |
| test.cpp:127:17:127:22 | call to malloc | test.cpp:123:18:123:23 | call to getenv | test.cpp:127:24:127:41 | ... * ... | This allocation size is derived from $@ and might overflow | test.cpp:123:18:123:23 | call to getenv | user input (getenv) |
| test.cpp:127:24:127:41 | ... * ... | test.cpp:123:18:123:23 | call to getenv | test.cpp:127:24:127:27 | size | This allocation size is derived from $@ and might overflow | test.cpp:123:18:123:23 | call to getenv | user input (getenv) |
| test.cpp:134:3:134:8 | call to malloc | test.cpp:132:19:132:24 | call to getenv | test.cpp:134:10:134:27 | ... * ... | This allocation size is derived from $@ and might overflow | test.cpp:132:19:132:24 | call to getenv | user input (getenv) |
| test.cpp:134:10:134:27 | ... * ... | test.cpp:132:19:132:24 | call to getenv | test.cpp:134:10:134:13 | size | This allocation size is derived from $@ and might overflow | test.cpp:132:19:132:24 | call to getenv | user input (getenv) |
| test.cpp:142:4:142:9 | call to malloc | test.cpp:138:19:138:24 | call to getenv | test.cpp:142:11:142:28 | ... * ... | This allocation size is derived from $@ and might overflow | test.cpp:138:19:138:24 | call to getenv | user input (getenv) |
| test.cpp:142:11:142:28 | ... * ... | test.cpp:138:19:138:24 | call to getenv | test.cpp:142:11:142:14 | size | This allocation size is derived from $@ and might overflow | test.cpp:138:19:138:24 | call to getenv | user input (getenv) |
| test.cpp:215:14:215:19 | call to malloc | test.cpp:227:24:227:29 | call to getenv | test.cpp:215:21:215:21 | s | This allocation size is derived from $@ and might overflow | test.cpp:227:24:227:29 | call to getenv | user input (getenv) |
| test.cpp:221:14:221:19 | call to malloc | test.cpp:227:24:227:29 | call to getenv | test.cpp:221:21:221:21 | s | This allocation size is derived from $@ and might overflow | test.cpp:227:24:227:29 | call to getenv | user input (getenv) |
| test.cpp:229:2:229:7 | call to malloc | test.cpp:227:24:227:29 | call to getenv | test.cpp:229:9:229:18 | local_size | This allocation size is derived from $@ and might overflow | test.cpp:227:24:227:29 | call to getenv | user input (getenv) |
| test.cpp:231:2:231:7 | call to malloc | test.cpp:201:14:201:19 | call to getenv | test.cpp:231:9:231:24 | call to get_tainted_size | This allocation size is derived from $@ and might overflow | test.cpp:201:14:201:19 | call to getenv | user input (getenv) |
48 changes: 47 additions & 1 deletion cpp/ql/test/query-tests/Security/CWE/CWE-190/semmle/TaintedAllocationSize/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5,8 +5,8 @@ typedef struct {} FILE;

void *malloc(size_t size);
void *realloc(void *ptr, size_t size);
void free(void *ptr);
int atoi(const char *nptr);

struct MyStruct
{
char data[256];
Expand Down Expand Up @@ -190,3 +190,49 @@ void more_bounded_tests() {
}
}
}

size_t get_untainted_size()
{
return 10 * sizeof(int);
}

size_t get_tainted_size()
{
return atoi(getenv("USER")) * sizeof(int);
}

size_t get_bounded_size()
{
size_t s = atoi(getenv("USER")) * sizeof(int);

if (s < 0) { s = 0; }
if (s > 100) { s = 100; }

return s;
}

void *my_alloc(size_t s) {
void *ptr = malloc(s); // [UNHELPFUL RESULT]

return ptr;
}

void my_func(size_t s) {
void *ptr = malloc(s); // BAD

free(ptr);
}

void more_cases() {
int local_size = atoi(getenv("USER")) * sizeof(int);

malloc(local_size); // BAD
malloc(get_untainted_size()); // GOOD
malloc(get_tainted_size()); // BAD
malloc(get_bounded_size()); // GOOD

my_alloc(100); // GOOD
my_alloc(local_size); // BAD [NOT DETECTED IN CORRECT LOCATION]
my_func(100); // GOOD
my_func(local_size); // GOOD
}