Add `CSnapshot::IsValid` to check if a snapshot unpacked from a snapshot delta or demo is valid:
- ensure number of items and data size are not negative
- ensure that the actual size of the snapshot matches the size derived from its member variables
- ensure item offsets are within the valid range
- ensure item sizes are not negative
Add `CSnapshot::TotalSize` and `CSnapshot::OffsetSize` utility functions.
Minor improvements to related error messages.
Fixes buffer overflow:
```
==47744==ERROR: AddressSanitizer: global-buffer-overflow on address 0x558618e3767f at pc 0x558614b9bdfb bp 0x7ffe58a32cd0 sp 0x7ffe58a32cc0
READ of size 4 at 0x558618e3767f thread T0
0x558614b9bdfa in CSnapshotItem::Type() const src/engine/shared/snapshot.h:16
0x558615c3c911 in CSnapshot::GetItemType(int) const src/engine/shared/snapshot.cpp:29
0x558614aebaba in CClient::UnpackAndValidateSnapshot(CSnapshot*, CSnapshot*) src/engine/client/client.cpp:2264
0x558614af87cb in CClient::OnDemoPlayerSnapshot(void*, int) src/engine/client/client.cpp:2598
0x558615b9db1a in CDemoPlayer::DoTick() src/engine/shared/demo.cpp:659
0x558615babd3f in CDemoPlayer::Update(bool) src/engine/shared/demo.cpp:1007
0x558614afb08b in CClient::Update() src/engine/client/client.cpp:2686
0x558614b1d9eb in CClient::Run() src/engine/client/client.cpp:3296
0x558614b8e64f in main src/engine/client/client.cpp:4761
```
And fixes a buffer overflow that manifests itself as an internal ASan error:
```
=================================================================
==4755==AddressSanitizer CHECK failed: ../../../../src/libsanitizer/asan/asan_descriptions.cc:79 "((0 && "Address is not in memory and not in shadow?")) != (0)" (0x0, 0x0)
0x7f0bf5f368be in AsanCheckFailed ../../../../src/libsanitizer/asan/asan_rtl.cc:72
0x7f0bf5f54eee in __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) ../../../../src/libsanitizer/sanitizer_common/sanitizer_termination.cc:77
0x7f0bf5e4cb6f in GetShadowKind ../../../../src/libsanitizer/asan/asan_descriptions.cc:79
0x7f0bf5e4cb6f in __asan::GetShadowAddressInformation(unsigned long, __asan::ShadowAddressDescription*) ../../../../src/libsanitizer/asan/asan_descriptions.cc:95
0x7f0bf5e4cb6f in __asan::GetShadowAddressInformation(unsigned long, __asan::ShadowAddressDescription*) ../../../../src/libsanitizer/asan/asan_descriptions.cc:92
0x7f0bf5e4e386 in __asan::AddressDescription::AddressDescription(unsigned long, unsigned long, bool) ../../../../src/libsanitizer/asan/asan_descriptions.cc:440
0x7f0bf5e50e94 in __asan::ErrorGeneric::ErrorGeneric(unsigned int, unsigned long, unsigned long, unsigned long, unsigned long, bool, unsigned long) ../../../../src/libsanitizer/asan/asan_errors.cc:380
0x7f0bf5f35f4d in __asan::ReportGenericError(unsigned long, unsigned long, unsigned long, unsigned long, bool, unsigned long, unsigned int, bool) ../../../../src/libsanitizer/asan/asan_report.cc:460
0x7f0bf5e86f5e in __interceptor_memset ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:762
0x558234873f1d in mem_zero src/base/system.cpp:213
0x55823481fc27 in CSnapshotBuilder::NewItem(int, int, int) src/engine/shared/snapshot.cpp:675
0x55823481be65 in CSnapshotDelta::UnpackDelta(CSnapshot*, CSnapshot*, void const*, int) src/engine/shared/snapshot.cpp:380
0x558234776641 in CDemoPlayer::DoTick() src/engine/shared/demo.cpp:631
0x5582347861a9 in CDemoPlayer::Update(bool) src/engine/shared/demo.cpp:1007
0x5582336d4c7d in CClient::Update() src/engine/client/client.cpp:2695
0x5582336f75dd in CClient::Run() src/engine/client/client.cpp:3305
0x558233768241 in main src/engine/client/client.cpp:4770
```
Fix pointer and pointer array variable naming
Huge renaming to match our rules
Used regex: (?!(return|delete)\b)\b\w+ (m_|ms_|g_|gs_|s_)[^a]\w+\[
(?!(return|delete)\b)\b\w+ (?!(m_|ms_|g_|gs_|s_))[^a]\w+\[
Further format static variables
Format almost all pointer names accordingly
Used regex: (?!(return)\b)\b\w+
\*(?!(m_p|p|s_p|m_ap|s_ap|g_p|g_ap|ap|gs_ap|ms_ap|gs_p|ms_p))\w+\b[^:\(p]
clang-format
Fix CI fail
Fix misnamed non pointer as pointer and non array as array
Used regex: (?!(return|delete)\b)\b\w+ (m_|ms_|g_|gs_|s_)p\w+\b
(?!return\b)\b\w+ (ms_|m_|g_|gs_|s_)a\w+\b[^\[]
clang-format
Revert to SCREAMING_SNAKE_CASE and reinstate dead code
4340: Add functions for packing/unpacking int/unsigned using char arrays r=heinrich5991 a=Robyt3
Add `uint_to_bytes_be` and `bytes_be_to_uint` functions from upstream and use them where applicable to reduce duplicate code.
## Checklist
- [X] Tested the change ingame
- [ ] Provided screenshots if it is a visual change
- [ ] Tested in combination with possibly related configuration options
- [ ] Written a unit test if it works standalone, system.c especially
- [ ] Considered possible null pointers and out of bounds array indexing
- [ ] Changed no physics that affect existing maps
- [ ] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-addresssanitizer--undefinedbehavioursanitizer-or-valgrinds-memcheck) (optional)
4350: Fix map_extract r=heinrich5991 a=def-
Reported by cheeser0613
<!-- What is the motivation for the changes of this pull request -->
## Checklist
- [x] Tested the change ingame
- [ ] Provided screenshots if it is a visual change
- [ ] Tested in combination with possibly related configuration options
- [ ] Written a unit test if it works standalone, system.c especially
- [x] Considered possible null pointers and out of bounds array indexing
- [x] Changed no physics that affect existing maps
- [x] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-addresssanitizer--undefinedbehavioursanitizer-or-valgrinds-memcheck) (optional)
Co-authored-by: Robert Müller <robert.mueller@uni-siegen.de>
Co-authored-by: def <dennis@felsin9.de>
and mark some false positives
/media/ddnet/src/engine/client/backend_sdl.cpp:329:30: warning: Call to 'malloc' has an allocation size of 0 bytes [clang-analyzer-optin.portability.UnixAPI]
Purely automatic change. In case of conflict with this change, apply the
other change and rerun the formatting to restore it:
$ python scripts/fix_style.py
2070: Fix demo recording with broken maps r=heinrich5991 a=Learath2
Apparently there are maps out there with broken headers advertising the wrong map size. This allows demos to be recorded on those.
Example of such a map is `ctf4_old_d668e9fa_2f472051b26b6bffaa4af8990cf882cafd6364e00e1333b77762cb9911e49464.map`
Hosted on `Allround Network`
Reported by teini94 on discord
Co-authored-by: Learath <learath2@gmail.com>
