Re: [Lldb-commits] [lldb] r346812 - Fix a bug in the parsing of the LC_BUILD_VERSION Mach-O load command.

[Davide Italiano via lldb-commits]

Thanks!
On Tue, Nov 13, 2018 at 3:17 PM Adrian Prantl via lldb-commits
<lldb-commits@lists.llvm.org> wrote:
>
> Author: adrian
> Date: Tue Nov 13 15:14:37 2018
> New Revision: 346812
>
> URL: http://llvm.org/viewvc/llvm-project?rev=346812&view=rev
> Log:
> Fix a bug in the parsing of the LC_BUILD_VERSION Mach-O load command.
>
> LC_BUILD_VERSION records are of variable length. The original code
> would use uninitialized memory when the size of a record was exactly 24.
>
> rdar://problem/46032185
>
> Added:
>     lldb/trunk/lit/Modules/lc_build_version_notools.yaml
>       - copied, changed from r346787, 
> lldb/trunk/lit/Modules/lc_build_version.yaml
> Modified:
>     lldb/trunk/lit/Modules/lc_build_version.yaml
>     lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
>
> Modified: lldb/trunk/lit/Modules/lc_build_version.yaml
> URL: 
> http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/Modules/lc_build_version.yaml?rev=346812&r1=346811&r2=346812&view=diff
> ==============================================================================
> --- lldb/trunk/lit/Modules/lc_build_version.yaml (original)
> +++ lldb/trunk/lit/Modules/lc_build_version.yaml Tue Nov 13 15:14:37 2018
> @@ -1,6 +1,6 @@
>  # RUN: yaml2obj %s > %t.out
>  # RUN: lldb-test symbols %t.out | FileCheck %s
> -# REQUIRES: darwin
> +# REQUIRES: system-darwin
>  # Test that the deployment target is parsed from the load commands.
>  # CHECK: x86_64-apple-macosx10.14.0
>  --- !mach-o
>
> Copied: lldb/trunk/lit/Modules/lc_build_version_notools.yaml (from r346787, 
> lldb/trunk/lit/Modules/lc_build_version.yaml)
> URL: 
> http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/Modules/lc_build_version_notools.yaml?p2=lldb/trunk/lit/Modules/lc_build_version_notools.yaml&p1=lldb/trunk/lit/Modules/lc_build_version.yaml&r1=346787&r2=346812&rev=346812&view=diff
> ==============================================================================
> --- lldb/trunk/lit/Modules/lc_build_version.yaml (original)
> +++ lldb/trunk/lit/Modules/lc_build_version_notools.yaml Tue Nov 13 15:14:37 
> 2018
> @@ -1,6 +1,6 @@
>  # RUN: yaml2obj %s > %t.out
>  # RUN: lldb-test symbols %t.out | FileCheck %s
> -# REQUIRES: darwin
> +# REQUIRES: system-darwin
>  # Test that the deployment target is parsed from the load commands.
>  # CHECK: x86_64-apple-macosx10.14.0
>  --- !mach-o
> @@ -10,7 +10,7 @@ FileHeader:
>    cpusubtype:      0x80000003
>    filetype:        0x00000002
>    ncmds:           14
> -  sizeofcmds:      744
> +  sizeofcmds:      738
>    flags:           0x00200085
>    reserved:        0x00000000
>  LoadCommands:
> @@ -119,14 +119,11 @@ LoadCommands:
>      cmdsize:         24
>      uuid:            8F41E140-23B9-3720-AC28-4E7AF9D159BA
>    - cmd:             LC_BUILD_VERSION
> -    cmdsize:         32
> +    cmdsize:         24
>      platform:        1
>      minos:           658944
>      sdk:             658944
> -    ntools:          1
> -    Tools:
> -      - tool:            3
> -        version:         26738944
> +    ntools:          0
>    - cmd:             LC_SOURCE_VERSION
>      cmdsize:         16
>      version:         0
>
> Modified: lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
> URL: 
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp?rev=346812&r1=346811&r2=346812&view=diff
> ==============================================================================
> --- lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp (original)
> +++ lldb/trunk/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp Tue Nov 
> 13 15:14:37 2018
> @@ -5027,24 +5027,28 @@ bool ObjectFileMachO::GetArchitecture(co
>          const lldb::offset_t cmd_offset = offset;
>          if (data.GetU32(&offset, &load_cmd, 2) == NULL)
>            break;
> -
> -        if (load_cmd.cmd == llvm::MachO::LC_BUILD_VERSION) {
> -          struct build_version_command build_version;
> -          if (load_cmd.cmdsize != sizeof(build_version))
> +        do {
> +          if (load_cmd.cmd == llvm::MachO::LC_BUILD_VERSION) {
> +            struct build_version_command build_version;
> +            if (load_cmd.cmdsize < sizeof(build_version)) {
> +              // Malformed load command.
> +              break;
> +            }
>              if (data.ExtractBytes(cmd_offset, sizeof(build_version),
>                                    data.GetByteOrder(), &build_version) == 0)
> -              continue;
> -          MinOS min_os(build_version.minos);
> -          OSEnv os_env(build_version.platform);
> -          if (os_env.os_type.empty())
> -            continue;
> -          os << os_env.os_type << min_os.major_version << '.'
> -             << min_os.minor_version << '.' << min_os.patch_version;
> -          triple.setOSName(os.str());
> -          if (!os_env.environment.empty())
> -            triple.setEnvironmentName(os_env.environment);
> -          return true;
> -        }
> +              break;
> +            MinOS min_os(build_version.minos);
> +            OSEnv os_env(build_version.platform);
> +            if (os_env.os_type.empty())
> +              break;
> +            os << os_env.os_type << min_os.major_version << '.'
> +               << min_os.minor_version << '.' << min_os.patch_version;
> +            triple.setOSName(os.str());
> +            if (!os_env.environment.empty())
> +              triple.setEnvironmentName(os_env.environment);
> +            return true;
> +          }
> +        } while (0);
>          offset = cmd_offset + load_cmd.cmdsize;
>        }
>
>
>
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