Add the BufferSize argument constraint to fread and fwrite. This change
itself makes it possible to discover a security critical case, described
in SEI-CERT ARR38-C.
We also add the not-null constraint on the 3rd arguments.
In this patch, I also remove those lambdas that don't take any
parameters (Fwrite, Fread, Getc), thus making the code better
structured.
Differential Revision: https://reviews.llvm.org/D87081
Hidden checkers (those marked with Hidden in Checkers.td) are meant for
development purposes only, and are only displayed under
-analyzer-checker-help-developer, so users shouldn't see reports from them.
I moved StdLibraryFunctionsArg checker to the unix package from apiModeling as
it violated this rule. I believe this change doesn't deserve a different
revision because it is in alpha, and the name is so bad anyways I don't
immediately care where it is, because we'll have to revisit it soon enough.
Differential Revision: https://reviews.llvm.org/D81750
Summary:
In this patch I am trying to get rid of the `Irrelevant` types from the
signatures of the functions from the standard C library. For that I've
introduced `lookupType()` to be able to lookup arbitrary types in the global
scope. This makes it possible to define the signatures precisely.
Note 1) `fread`'s signature is now fixed to have the proper `FILE *restrict`
type when C99 is the language.
Note 2) There are still existing `Irrelevant` types, but they are all from
POSIX. I am planning to address those together with the missing POSIX functions
(in D79433).
Reviewers: xazax.hun, NoQ, Szelethus, balazske
Subscribers: whisperity, baloghadamsoftware, szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy, dkrupp, gamesh411, Charusso, steakhal, ASDenysPetrov, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D80016
Summary:
Further develop the buffer size argumentum constraint so it can handle sizes
that we can get by multiplying two variables.
Reviewers: Szelethus, NoQ, steakhal
Subscribers: whisperity, xazax.hun, baloghadamsoftware, szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy, dkrupp, gamesh411, Charusso, ASDenysPetrov, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D77148
Summary:
Introducing a new argument constraint to confine buffer sizes. It is typical in
C APIs that a parameter represents a buffer and another param holds the size of
the buffer (or the size of the data we want to handle from the buffer).
Reviewers: NoQ, Szelethus, Charusso, steakhal
Subscribers: whisperity, xazax.hun, baloghadamsoftware, szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy, dkrupp, gamesh411, ASDenysPetrov, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D77066
It was enabled by default accidentally; still missing some important
features. Also it needs a better package because it doesn't boil down to
API modeling.
Differential Revision: https://reviews.llvm.org/D80213
Summary:
Currently we match the summary signature based on the arguments in the CallExpr.
There are a few problems with this approach.
1) Variadic arguments are handled badly. Consider the below code:
int foo(void *stream, const char *format, ...);
void test_arg_constraint_on_variadic_fun() {
foo(0, "%d%d", 1, 2); // CallExpr
}
Here the call expression holds 4 arguments, whereas the function declaration
has only 2 `ParmVarDecl`s. So there is no way to create a summary that
matches the call expression, because the discrepancy in the number of
arguments causes a mismatch.
2) The call expression does not handle the `restrict` type qualifier.
In C99, fwrite's signature is the following:
size_t fwrite(const void *restrict, size_t, size_t, FILE *restrict);
However, in a call expression, like below, the type of the argument does not
have the restrict qualifier.
void test_fread_fwrite(FILE *fp, int *buf) {
size_t x = fwrite(buf, sizeof(int), 10, fp);
}
This can result in an unmatches signature, so the summary is not applied.
The solution is to match the summary against the referened callee
`FunctionDecl` that we can query from the `CallExpr`.
Further patches will continue with additional refactoring where I am going to
do a lookup during the checker initialization and the signature match will
happen there. That way, we will not check the signature during every call,
rather we will compare only two `FunctionDecl` pointers.
Reviewers: NoQ, Szelethus, gamesh411, baloghadamsoftware
Subscribers: whisperity, xazax.hun, kristof.beyls, szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy, dkrupp, Charusso, steakhal, danielkiss, ASDenysPetrov, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D77410
Summary:
Previously we induced a state split if there were multiple argument
constraints given for a function. This was because we called
`addTransition` inside the for loop.
The fix is to is to store the state and apply the next argument
constraint on that. And once the loop is finished we call `addTransition`.
Reviewers: NoQ, Szelethus, baloghadamsoftware
Subscribers: whisperity, xazax.hun, szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy, dkrupp, gamesh411, C
Tags: #clang
Differential Revision: https://reviews.llvm.org/D76790
Gabor Marton