reformat_libyuv: Add ignore CFI annotation #1507
Conversation
There was a problem hiding this comment.
LGTM. I suggest some changes to the comments.
Note: Another simple solution would be to compile src/reformat_libyuv.c as C++ code. Then this file and libyuv itself will see libyuv's types in the libyuv namespace, and CFI will be happy. We will need to make sure this does not add a dependency on the C++ runtime library.
Ack. I agree that's another solution, but would rather get away with the annotation than meddling around the compilation settings for this file alone in various environments. |
libyuv is a C++ library and defines custom types (struct, enum, etc) in a namespace when conditionally compiled with a C++ compiler. When accessed from a C library like libavif, via a function pointer, this leads to signature mismatches in the CFI sanitizers since the C++ header file defines the types within the namespace and the C code has the types without the namespace. In order to avoid this CFI error, we tag some functions as an exception when being compiled with CFI enabled. For more details on clang's CFI see: https://clang.llvm.org/docs/ControlFlowIntegrity.html. For a simpler example of this bug, please see: https://github.com/vigneshvg/cpp_c_potential_cfi_bug Sample CFI failure in Chromium: crbug.com/1473228
Re-landing https://crrev.com/c/4763864 The underlying bug that was causing the CFI failures was fixed in libavif here: AOMediaCodec/libavif#1507 It was included in Chromium DEPS here: https://crrev.com/c/4794456 Also remove "-fsanitize-cfi-icall-generalize-pointers" from the libavif BUILD.gn since that is no longer necessary as the underlying libavif fix does it better by disabling cfi-icall checks for only one specific function. Test: blink_platform_unittests pass with CFI enabled. Bug: 1473228 Change-Id: I2453fcc077fa3235874ae660da17a2e9f86ca7c1 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4795633 Reviewed-by: Wan-Teh Chang <[email protected]> Commit-Queue: Vignesh Venkat <[email protected]> Cr-Commit-Position: refs/heads/main@{#1185915}
libyuv is a C++ library and defines custom types (struct, enum, etc) in a namespace when conditionally compiled with a C++ compiler. When accessed from a C library like libavif, via a function pointer, this leads to signature mismatches in the CFI sanitizers since the C++ header file defines the types within the namespace and the C code has the types without the namespace. In order to avoid this CFI error, we tag some functions as an exception when being compiled with CFI enabled.
For more details on clang's CFI see:
https://clang.llvm.org/docs/ControlFlowIntegrity.html.
For a simpler example of this bug, please see:
https://github.com/vigneshvg/cpp_c_potential_cfi_bug
Sample CFI failure in Chromium: crbug.com/1473228