[PATCH] Fix undefined behaviour
Marko Mäkelä <[email protected]> Sun, 4 Dec 2022 14:19:16 +0200
| Newsgroups | gmane.linux.vdr |
|---|---|
| Message-ID | <Y4yQRPMHC7twF1AQ@jyty> |
Another day, another sanitizer. After fixing issues reported by -fsanitize=address yesterday, I gave -fsanitize=undefined a try. The GCC documentation points to the clang documentation: https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html The issues related to cControl::player were tricky. In the end, I figured it out after setting UBSAN_OPTIONS=print_stacktrace=1 and setting a breakpoint on _Unwind_Backtrace(). The name of the reporting function in my system was __ubsan_handle_dynamic_type_cache_miss(), nothing about "vptr". Also, the diagnostics was misleadingly pointing to the body of the constructor, and not the initializer list where a data member was being assigned to before the base class had been initialized. The -fsanitize=undefined in clang might report more things. Next I may give -fsanitize=thread a try. GCC does not implement -fsanitize=memory (checking for the use of uninitialized memory) at all. It will require clang and libc++ (not libstdc++) and that all libraries except libc are built with -fsanitize=memory. If you are familiar with Valgrind's default memcheck tool, it is roughly comparable to the combination of -fsanitize=address and -fsanitize=memory. Marko _______________________________________________ vdr mailing list [email protected] https://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr
0001-Fix-GCC-8.3.0-fsanitize-undefined.patch
(text/x-diff, 4.1 KB)
From b69ff7105d4bb8d933f0214f34b103fda8e8b155 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= <[email protected]> Date: Sun, 4 Dec 2022 13:42:57 +0200 Subject: [PATCH] Fix GCC 8.3.0 -fsanitize=undefined sections.c:183:30: runtime error: variable length array bound evaluates to non-positive value 0 device.c:251:31: runtime error: variable length array bound evaluates to non-positive value 0 osd.h:301:37: runtime error: signed integer overflow: -2147483648 - 2147483647 cannot be represented in type 'int' osd.h:301:37: runtime error: signed integer overflow: -2147483647 - 2147483647 cannot be represented in type 'int' transfer.c:71:11: runtime error: member access within address 0x020f0428 which does not point to an object of type 'cTransferControl' dvbplayer.c:984:11: runtime error: member access within address 0x02a388d0 which does not point to an object of type 'cDvbPlayerControl' --- device.c | 2 +- dvbplayer.c | 3 ++- font.c | 3 ++- osd.h | 4 ++-- sections.c | 2 +- transfer.c | 3 ++- 6 files changed, 10 insertions(+), 7 deletions(-) diff --git a/device.c b/device.c index 4e987389..a770aa90 100644 --- a/device.c +++ b/device.c @@ -248,7 +248,7 @@ cDevice *cDevice::GetDevice(const cChannel *Channel, int Priority, bool LiveView { // Collect the current priorities of all CAM slots that can decrypt the channel: int NumCamSlots = CamSlots.Count(); - int SlotPriority[NumCamSlots]; + int SlotPriority[std::max(NumCamSlots, 1)]; int NumUsableSlots = 0; bool InternalCamNeeded = false; if (Channel->Ca() >= CA_ENCRYPTED_MIN) { diff --git a/dvbplayer.c b/dvbplayer.c index 2ee846b6..72bc46ad 100644 --- a/dvbplayer.c +++ b/dvbplayer.c @@ -981,8 +981,9 @@ bool cDvbPlayer::GetReplayMode(bool &Play, bool &Forward, int &Speed) // --- cDvbPlayerControl ----------------------------------------------------- cDvbPlayerControl::cDvbPlayerControl(const char *FileName, bool PauseLive) -:cControl(player = new cDvbPlayer(FileName, PauseLive)) +:cControl(new cDvbPlayer(FileName, PauseLive)) { + player = static_cast<cDvbPlayer*>(cControl::player); } cDvbPlayerControl::~cDvbPlayerControl() diff --git a/font.c b/font.c index 8b37798c..c78b1a15 100644 --- a/font.c +++ b/font.c @@ -74,7 +74,8 @@ cGlyph::cGlyph(uint CharCode, FT_GlyphSlotRec_ *GlyphData) rows = GlyphData->bitmap.rows; pitch = GlyphData->bitmap.pitch; bitmap = MALLOC(uchar, rows * pitch); - memcpy(bitmap, GlyphData->bitmap.buffer, rows * pitch); + if (int bytes = rows * pitch) + memcpy(bitmap, GlyphData->bitmap.buffer, bytes); } cGlyph::~cGlyph() diff --git a/osd.h b/osd.h index 77722662..7a293321 100644 --- a/osd.h +++ b/osd.h @@ -298,8 +298,8 @@ public: struct tArea { int x1, y1, x2, y2; int bpp; - int Width(void) const { return x2 - x1 + 1; } - int Height(void) const { return y2 - y1 + 1; } + int Width(void) const { return x2 < 0 ? 0 : x2 - x1 + 1; } + int Height(void) const { return y2 < 0 ? 0 : y2 - y1 + 1; } bool Intersects(const tArea &Area) const { return !(x2 < Area.x1 || x1 > Area.x2 || y2 < Area.y1 || y1 > Area.y2); } }; diff --git a/sections.c b/sections.c index 51a2823c..4d90b19c 100644 --- a/sections.c +++ b/sections.c @@ -180,7 +180,7 @@ void cSectionHandler::Action(void) startFilters = false; } int NumFilters = filterHandles.Count(); - pollfd pfd[NumFilters]; + pollfd pfd[std::max(NumFilters, 1)]; for (cFilterHandle *fh = filterHandles.First(); fh; fh = filterHandles.Next(fh)) { int i = fh->Index(); pfd[i].fd = fh->handle; diff --git a/transfer.c b/transfer.c index 88931e58..b888910a 100644 --- a/transfer.c +++ b/transfer.c @@ -68,8 +68,9 @@ void cTransfer::Receive(const uchar *Data, int Length) cDevice *cTransferControl::receiverDevice = NULL; cTransferControl::cTransferControl(cDevice *ReceiverDevice, const cChannel *Channel) -:cControl(transfer = new cTransfer(Channel), true) +:cControl(new cTransfer(Channel), true) { + transfer = static_cast<cTransfer*>(player); ReceiverDevice->AttachReceiver(transfer); receiverDevice = ReceiverDevice; } -- 2.38.1