Summary:
The Java frontend translates exceptions by assigning them to the return value.
This leads to weird behavior when the return type of the function is void.
Already handled one case of this in Quandary (ignoring assignments of exceptions to return value), but was missing the case where null is assigned to the return value.
The frontend does this to "clear" the value of previously assigned exceptions.
Reviewed By: jeremydubreil
Differential Revision: D4294060
fbshipit-source-id: 6bef5ef
Summary:
Functions related to source files were already namespaced by `source_file_` prefix. Make separate module for them.
In high level it replaces all `source_file_` with `SourceFile.` and then fixes all remaining compilation errors
Reviewed By: jvillard
Differential Revision: D4299053
fbshipit-source-id: 20b1d39
Summary:
Trying to stop other users of the trace domain from making the mistake that Quandary made before D4234766.
This should also improve the performance of Quandary, since the filtering of FP's is now done before building up the full interprocedural trace (which requires disk reads).
Reviewed By: jeremydubreil
Differential Revision: D4234770
fbshipit-source-id: e7e9291
Summary:
We only ought to report a source-sink flow at the call site where the sink is introduced.
Otherwise, we will report silly false positives.
Reviewed By: jeremydubreil
Differential Revision: D4234766
fbshipit-source-id: 118051f
Summary: Noticed this when I was writing the documentation for the abstract interpretation framework and was curious about why `Ondemand.analyze_proc` needs the type environment. It turns out that the type environment is only used to transform/normalize Infer bi-abduction specs before storing them to disk, but this can be done elsewhere. Doing this normalization elsewhere simplifies the on-demand API, which is a win for all of its clients.
Reviewed By: cristianoc
Differential Revision: D4241279
fbshipit-source-id: 957b243
Summary:
In Java, we handle unknown code by propagating behavior from the parameters of the unknown function call to the return value (or constructed object, in the case of a constructor). But we do this in a somewhat silly way--generating a new summary with these semantics at each unknown call site. Instead, this diff introduces these two options as predefined behaviors and adds specialized code for them.
As a side effect of this approach, unknown functions are no longer counted as passthroughs. This is ok; the original behavior was less of a reasoned decision and more of an unintended consequence of the way we decided to handle unknown code.
This new approach ought to be more efficient than the old one, and as a virtuous side effect it will be easier to specify how to handle unknown code in other languages like C++.
Reviewed By: jeremydubreil
Differential Revision: D4205624
fbshipit-source-id: bf97445
Summary:
Let's introduce some concepts. A "known unknown" function is one for which no Java code exists (e.g., `native`, `abstract`, and `interface methods`). An "unknown unknown" function is one for which Java code may or may not exist, but we don't have the code or we choose not to analyze it (e.g., non-modeled methods from the core Java or Android libraries).
Previously, Quandary handled both known unknowns and unknown unknowns by propagating taint from the parameters of the unknown function to its return value. It turns out that it is really expensive to do this for known unknown functions. D4142697 was the diff that starting handling known unknown functions in this way, and bisecting shows that it was the start of the recent performance problems for Quandary.
This diff essentially reverts D4142697 by handling known unknowns as skips instead. Pragmatically, doing the propagation trick for Java/Android library functions (e.g., `String` functions!) matters much more, so i'm not too worried about the missed behaviors from this. Ideally, we will go back to the old handling once performance has improved (have lots of ideas there). But I need this to unblock me in the meantime.
Reviewed By: jeremydubreil
Differential Revision: D4205507
fbshipit-source-id: 79cb9c8
Summary: Generalizing jvillard's awesome work to include passthroughs in traces, then calling it from Quandary.
Reviewed By: jvillard
Differential Revision: D4172108
fbshipit-source-id: 0296c59
Summary: If a procedure is both a source and a sink for the same value, and it's a sink first, you will get a false positive when applying the summary for the procedure.
Reviewed By: cristianoc
Differential Revision: D4145246
fbshipit-source-id: 97f0022
Summary:
Analyses should handle methods whose code is unknown and methods whose summary is a no-op differently.
Previously, this was done correctly for some kinds of methods (e.g., native methods, which were recognized as unknown), but not for others (interface and abstract methods).
This diff makes sure we correctly treat all three kinds as unknown.
Reviewed By: jeremydubreil
Differential Revision: D4142697
fbshipit-source-id: c88cff3
Summary:
Our default strategy for handling unknown code is to propagate taint from the actuals to the return value.
But for commonly-used methods like `StringBuilder.append` (used every time you do `+` with a string in Java), this doesn't work.
The taint should be propagated to both the receiver and the return value in these cases.
I'm considering a solution where we always propagate taint to the receiver of unknown functions in the future, but I am concerned about the performance.
So let's stick with a few special string cases for now.
Reviewed By: cristianoc
Differential Revision: D4124355
fbshipit-source-id: 5b2a232
Summary: A must-have for reporting taint errors and any other interprocedural error where the trace is sufficiently complex.
Reviewed By: jvillard
Differential Revision: D4124072
fbshipit-source-id: 26b3b2b
Summary: A must-have for reporting taint errors and any other interprocedural error where the trace is sufficiently complex.
Reviewed By: jvillard
Differential Revision: D4106352
fbshipit-source-id: b2677e6
Summary:
See code comment about `throw exn` being translated as `return exn`.
This problem was revealed by D4081279, which started grabbing access paths from exceptions.
Reviewed By: jvillard
Differential Revision: D4096391
fbshipit-source-id: 9d91513
Summary:
this makes frontends no longer depend on SymExec.ml. `ModelBuiltins` was split into two modules:
- `BuiltinDecl` with procnames for builtins (used to determine whether some function is a builtin)
- `BuiltinDefn` with implementations used by `SymExec`
- they both have similar type defined in `BUILTINS.S` which makes sure that new builtin gets added into both modules.
During the refactor I ran some scripts:
`BuiltinDecl.ml`:
let X = create_procname "X"
cat BuiltinDecl.ml | grep "create_procname" | tail -70 | awk ' { print $1,$2,$3,$4,"\42"$2"\42"} '
then manually confirm string match. Exceptions:
"__exit" -> "_exit"
"objc_cpp_throw" -> "__infer_objc_cpp_throw"
__objc_dictionary_literal
nsArray_arrayWithObjects
nsArray_arrayWithObjectsCount
`BuiltinDefn.ml`:
let X = Builtin.register BuiltinDecl.X execute_X
cat BuiltinDecl.ml | grep "create_procname" | tail -70 | awk ' { print $1,$2,$3,"Builtin.register BuiltinDecl."$2,"execute_"$2} '
then, fix all compilation problems
Reviewed By: jberdine
Differential Revision: D3951035
fbshipit-source-id: f059602
Summary:
Right now, taint gets lost if it flows into a constructor or procedure whose implementation is missing.
Since the core Java (e.g., String) and Android classes (e.g, Intent) are among these, this is bad.
We could handle this by writing a bunch of models instead, but that would be a lot of work (plus we may still miss cases).
Reviewed By: jvillard
Differential Revision: D4051591
fbshipit-source-id: 65851c8
Summary:
Before, if I wrote code like
```
x = src()
sink(x)
sink(x)
```
we would report three times instead of two.
The first flow would be double-reported.
Reviewed By: jeremydubreil
Differential Revision: D4024678
fbshipit-source-id: fcd5b30
Summary:
Change Sil.Call instruction to have only a single optional return
identifier, insted of a list. Essentially none of the code handled
multiple return identifiers. Also, add the type of the return
identitifier to Call instructions.
Reviewed By: sblackshear
Differential Revision: D3919358
fbshipit-source-id: d2d4f72
Summary:
The global reference `DB.current_source` is used internally in the module DB, by all the front-ends, and directly and indirectly by the back-end, including saving and restoring the state in case of on-demand procedure calls. In particular, it is heavily used in printing functions.
This diff cleans up the flow of information about what the current file is, making it explicit, and removes the reference.
Reviewed By: jberdine
Differential Revision: D3901247
fbshipit-source-id: ef596bd
Summary:
This diff removes the redundancy in the representation of types where
struct types could be represented either directly using Tstruct or
indirectly using Tvar to refer to the type environment. A consequence
is that it is much harder to construct large type values.
Reviewed By: sblackshear, cristianoc
Differential Revision: D3839753
fbshipit-source-id: cf04ea5
Josh Berdine
Sam Blackshear
Andrzej Kotulski
Cristiano Calcagno