From 7f33dfc100b2da0f158494534138a2d8b4f95100 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Mon, 29 Jul 2024 20:16:11 +0300 Subject: libcamera: Avoid variable-length arrays Unlike in C where they have been standardized since C99, variable-length arrays in C++ are an extension supported by gcc and clang. Clang started warning about this with -Wall in version 18: src/libcamera/ipc_unixsocket.cpp:250:11: error: variable length arrays in C++ are a Clang extension [-Werror,-Wvla-cxx-extension] 250 | char buf[CMSG_SPACE(num * sizeof(uint32_t))]; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ One simple option is to disable the warning. However, usage of VLAs in C++ is discouraged by some, usually due to security reasons, based on the rationale that developers are often unaware of unintentional use of VLAs and how they may affect the security of the code when the array size is not properly validated. This rationale may sound dubious, as the most commonly proposed fix is to replace VLAs with vectors (or just arrays dynamically allocated with new() wrapped in unique pointers), without adding any size validation. This will not produce much better results. However, keeping the VLA warning and converting the code to dynamic allocation may still be slightly better, as it can prompt developers to notice VLAs and check if size validation is required. For these reasons, convert all VLAs to std::vector. Most of the VLAs don't need extra size validation, as the size is bound through different constraints (e.g. image width for line buffers). An arguable exception may be the buffers in IPCUnixSocket::sendData() and IPCUnixSocket::recvData() as the number of fds is not bound-checked locally, but we will run out of file descriptors before we could overflow the buffer size calculation. Signed-off-by: Laurent Pinchart Reviewed-by: Milan Zamazal Acked-by: Jacopo Mondi --- src/apps/common/dng_writer.cpp | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'src/apps/common/dng_writer.cpp') diff --git a/src/apps/common/dng_writer.cpp b/src/apps/common/dng_writer.cpp index 355433b0..ac461951 100644 --- a/src/apps/common/dng_writer.cpp +++ b/src/apps/common/dng_writer.cpp @@ -11,6 +11,7 @@ #include #include #include +#include #include @@ -544,7 +545,7 @@ int DNGWriter::write(const char *filename, const Camera *camera, * or a thumbnail scanline. The latter will always be much smaller than * the former as we downscale by 16 in both directions. */ - uint8_t scanline[(config.size.width * info->bitsPerSample + 7) / 8]; + std::vector scanline((config.size.width * info->bitsPerSample + 7) / 8); toff_t rawIFDOffset = 0; toff_t exifIFDOffset = 0; @@ -644,10 +645,10 @@ int DNGWriter::write(const char *filename, const Camera *camera, /* Write the thumbnail. */ const uint8_t *row = static_cast(data); for (unsigned int y = 0; y < config.size.height / 16; y++) { - info->thumbScanline(*info, &scanline, row, + info->thumbScanline(*info, scanline.data(), row, config.size.width / 16, config.stride); - if (TIFFWriteScanline(tif, &scanline, y, 0) != 1) { + if (TIFFWriteScanline(tif, scanline.data(), y, 0) != 1) { std::cerr << "Failed to write thumbnail scanline" << std::endl; TIFFClose(tif); @@ -747,9 +748,9 @@ int DNGWriter::write(const char *filename, const Camera *camera, /* Write RAW content. */ row = static_cast(data); for (unsigned int y = 0; y < config.size.height; y++) { - info->packScanline(&scanline, row, config.size.width); + info->packScanline(scanline.data(), row, config.size.width); - if (TIFFWriteScanline(tif, &scanline, y, 0) != 1) { + if (TIFFWriteScanline(tif, scanline.data(), y, 0) != 1) { std::cerr << "Failed to write RAW scanline" << std::endl; TIFFClose(tif); -- cgit v1.2.1