llvm-svn: 342148

When used in cross-DSO mode, CFI will generate calls to special functions rather than trap instructions.  For example, instead of generating

if (!InlinedFastCheck(f))
  abort();
call *f

CFI generates

if (!InlinedFastCheck(f))
  __cfi_slowpath(CallSiteTypeId, f);
call *f

This patch teaches cfi-verify to recognize calls to __cfi_slowpath and abort and treat them as trap functions.

In addition to normal symbols, we also parse the dynamic relocations to handle cross-DSO calls in libraries.

We also extend cfi-verify to recognize other patterns that occur using cross-DSO.  For example, some indirect calls are not guarded by a branch to a trap but instead follow a call to __cfi_slowpath.  For example:

if (!InlinedFastCheck(f))
  call *f
else {
  __cfi_slowpath(CallSiteTypeId, f);
  call *f
}

In this case, the second call to f is not marked as protected by the current code.  We thus recognize if indirect calls directly follow a call to a function that will trap on CFI violations and treat them as protected.

We also ignore indirect calls in the PLT, since on AArch64 each entry contains an indirect call that should not be protected by CFI, and these are labeled incorrectly when debug information is not present.

Differential Revision: https://reviews.llvm.org/D49383

llvm-svn: 340612

As suggested in the review for r337007, this makes cfi-verify abort on unsupported targets instead of producing incorrect results.  It also updates the design document to reflect this.

Differential Revision: https://reviews.llvm.org/D49304

llvm-svn: 337181

This patch adds support for AArch64 to cfi-verify.

This required three changes to cfi-verify.  First, it generalizes checking if an instruction is a trap by adding a new isTrap flag to TableGen (and defining it for x86 and AArch64).  Second, the code that ensures that the operand register is not clobbered between the CFI check and the indirect call needs to allow a single dereference (in x86 this happens as part of the jump instruction).  Third, we needed to ensure that return instructions are not counted as indirect branches.  Technically, returns are indirect branches and can be covered by CFI, but LLVM's forward-edge CFI does not protect them, and x86 does not consider them, so we keep that behavior.

In addition, we had to improve AArch64's code to evaluate the branch target of a MCInst to handle calls where the destination is not the first operand (which it often is not).

Differential Revision: https://reviews.llvm.org/D48836

llvm-svn: 337007

llvm-svn: 331835

llvm-svn: 320631

Summary:
This patch adds another failure mode for `validateCFIProtection(..)`, wherein any register that affects the indirect control flow instruction is clobbered to between the CFI-check and the instruction's execution.

Also includes a modification to make MCInstrDesc::hasDefOfPhysReg public.

Reviewers: vlad.tsyrklevich

Reviewed By: vlad.tsyrklevich

Subscribers: llvm-commits, pcc, kcc

Differential Revision: https://reviews.llvm.org/D39820

llvm-svn: 318238

Allows users to view GraphResult objects in a DOT directed-graph format. This feature can be turned on through the --print-graphs flag.

Also enabled pretty-printing of instructions in output. Together these features make analysis of unprotected CF instructions much easier by providing a visual control flow graph.

Reviewers: pcc

Subscribers: llvm-commits, kcc, vlad.tsyrklevich

Differential Revision: https://reviews.llvm.org/D39819

llvm-svn: 318211

Refactors the behaviour of building graphs out of FileAnalysis, allowing for analysis of the GraphResult by the callee without having to rebuild the graph. Means when we want to analyse the constructed graph (planned for later revisions), we don't do repeated work.

Also makes CFI verification in FileAnalysis now return an enum that allows us to differentiate why something failed, not just that it did/didn't fail.

Reviewers: vlad.tsyrklevich

Subscribers: kcc, pcc, llvm-commits

Differential Revision: https://reviews.llvm.org/D39764

llvm-svn: 317927

Adds the blacklist behaviour to llvm-cfi-verify. Now will calculate which lines caused expected failures in the blacklist and reports the number of affected indirect CF instructions for each blacklist entry.

Also moved DWARF checking after instruction analysis to improve performance significantly - unrolling the inlining stack is expensive.

Reviewers: vlad.tsyrklevich

Subscribers: aprantl, pcc, kcc, llvm-commits

Differential Revision: https://reviews.llvm.org/D39750

llvm-svn: 317743

Move the LLVMCFIVerify project into the Libraries folder on IDEs like Visual Studio rather than leave it in the root directory. NFC.

llvm-svn: 317415

Adds blacklist parsing behaviour for filtering results into four categories:

 - Expected Protected: Things that are not in the blacklist and are protected.
 - Unexpected Protected: Things that are in the blacklist and are protected.
 - Expected Unprotected: Things that are in the blacklist and are unprotected.
 - Unexpected Unprotected: Things that are not in the blacklist and are unprotected.

 now can optionally be invoked with a second command line argument, which specifies the blacklist file that the binary was built with.

Current  statistics for chromium:

Reviewers: vlad.tsyrklevich

Subscribers: mgorny, llvm-commits, pcc, kcc

Differential Revision: https://reviews.llvm.org/D39525

llvm-svn: 317364

cl::opt<uint64_t> fails when parsing command line arguments.

See https://bugs.llvm.org/show_bug.cgi?id=19665.

Reviewers: pcc

Subscribers: mgorny, llvm-commits, kcc

Differential Revision: https://reviews.llvm.org/D38657

llvm-svn: 317141

Summary: Help differentiate code and data by parsing DWARF information. This will reduce false positive rates where data is placed in executable sections and is mistakenly parsed as code, resulting in an inflation in the number of indirect CF instructions (and hence an inflation of the number of unprotected).

Also prints the DWARF line data around the region of each indirect CF instruction.

Reviewers: pcc

Subscribers: probinson, llvm-commits, vlad.tsyrklevich, mgorny, aprantl, kcc

Differential Revision: https://reviews.llvm.org/D38654

llvm-svn: 317050

Add a CFI protection check that is implemented by building a graph and inspecting the output to deduce if the indirect CF instruction is CFI protected. Also added the output of this instruction to printIndirectInstructions().

Reviewers: vlad.tsyrklevich

Subscribers: llvm-commits, kcc, pcc, mgorny

Differential Revision: https://reviews.llvm.org/D38428

llvm-svn: 316610

Patched out from D38427.

Reviewers: vlad.tsyrklevich

Reviewed By: vlad.tsyrklevich

Subscribers: llvm-commits, kcc, pcc, mgorny

Differential Revision: https://reviews.llvm.org/D39197

llvm-svn: 316375

Implement a localised graph builder for indirect control flow
instructions. Main interface is through GraphBuilder::buildFlowGraph,
which will build a flow graph around an indirect CF instruction. Various
modifications to FileVerifier are also made to const-expose some members
needed for machine code analysis done by the graph builder.

Reviewers: vlad.tsyrklevich

Reviewed By: vlad.tsyrklevich

Subscribers: llvm-commits, kcc, pcc

Differential Revision: https://reviews.llvm.org/D38427

llvm-svn: 316372

Accidently merged an incomplete upstream patch in 10e6ee563a6b5ca498f27972ca6dbe6c308f1ac2 - reverting the changes.

llvm-svn: 316359

llvm-svn: 316358

Summary:
llvm-cfi-verify (D38379) introduced a potential build failure when compiling with `-DLLVM_BUILD_LLVM_DYLIB=ON -DLLVM_LINK_LLVM_DYLIB=ON`. Specific versions of cmake seem to treat the `add_subdirectory()` rule differently. It seems as if old versions of cmake BFS these rules, adding them to the fringe for expansion later. Newer versions of cmake seem to immediately execute CMakeFiles that are present in this subdirectory.

If the subdirectory is expanded through the fringe, the globbing resultant from `llvm_add_implicit_projects()` from `cmake/modules/AddLLVM.cmake:1012` means that `tools/llvm-shlib/CMakeFile.txt` gets executed before `tools/llvm-cfi-verify/lib/CMakeFile.txt`. As the latter CMakeFile adds a new library, this expansion order means that the library files required the unit tests in `unittests/tools/llvm-cfi-verify/` are not present in the dynamic library. This causes unit tests to fail as the required functions can't be found.

This change now ensures that the libraries created by `llvm-cfi-verify` are statically linked into the unit tests. As `tools/llvm-cfi-verify/lib` no longer adds anything to `llvm-shlib`, there should be no concern about the order-of-compilation.

Reviewers: skatkov, pcc

Reviewed By: skatkov, pcc

Subscribers: llvm-commits, kcc, pcc, aheejin, vlad.tsyrklevich, mgorny

Differential Revision: https://reviews.llvm.org/D39020

llvm-svn: 316059

Add instruction analysis and machinecode traversal helpers in
preparation for control flow graph generation implementation.

Reviewers: vlad.tsyrklevich

Reviewed By: vlad.tsyrklevich

Subscribers: mgorny, llvm-commits, pcc, kcc

Differential Revision: https://reviews.llvm.org/D38424

llvm-svn: 315528

Summary: Move llvm-cfi-verify into a class in preparation for CFI analysis to come.

Reviewers: vlad.tsyrklevich

Reviewed By: vlad.tsyrklevich

Subscribers: mgorny, llvm-commits, pcc, kcc

Differential Revision: https://reviews.llvm.org/D38379

llvm-svn: 315504