Alacritty: running `cat /dev/urandom` crashes alacritty

[awalgarg]

As the title says, running cat /dev/urandom consistently crashes alacritty. Apparently some random escape codes send it into a state where this condition is triggered: https://github.com/jwilm/alacritty/blob/master/src/term/mod.rs#L634. Here is a log with backtrace: https://linx.li/aomx2zxa.ext

Great project btw, good luck! :)

[jwilm]

Thanks for the report! At least the parser doesn't choke on it :).

There's a number of places where we don't coerce the cursor to be within the bounds of the grid. Doing so might fix this issue.

[jwilm]

Still panicking in a couple of places:

thread 'pty reader' panicked at 'ansi::ClearMode::Above not implemented', src/term/mod.rs:941
stack backtrace:
   1:     0x55be6fb2259a - std::sys::imp::backtrace::tracing::imp::write::h2b860f17b6b0f511
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:42
   2:     0x55be6fb2790f - std::panicking::default_hook::{{closure}}::hedea7d569eb1e6b8
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:349
   3:     0x55be6fb2750e - std::panicking::default_hook::he87e0c76c89c52a4
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:365
   4:     0x55be6fb27db7 - std::panicking::rust_panic_with_hook::h304127bde2d3d5e2
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:553
   5:     0x55be6fa006c4 - std::panicking::begin_panic::h1dc990fced681ffe
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:515
   6:     0x55be6fa042d5 - vte::Parser::perform_action::h26c5257024b70aee
                        at /home/jwilm/code/alacritty/<panic macros>:3
                        at /home/jwilm/code/alacritty/src/ansi.rs:556
                        at /home/jwilm/.cargo/registry/src/github.com-1ecc6299db9ec823/vte-0.1.2/src/lib.rs:205
   7:     0x55be6fa1507a - <alacritty::event_loop::EventLoop<Io>>::spawn::{{closure}}::h6e25bd11b2170a6c
                        at /home/jwilm/.cargo/registry/src/github.com-1ecc6299db9ec823/vte-0.1.2/src/lib.rs:158
                        at /home/jwilm/.cargo/registry/src/github.com-1ecc6299db9ec823/vte-0.1.2/src/lib.rs:137
                        at /home/jwilm/code/alacritty/src/ansi.rs:85
                        at /home/jwilm/code/alacritty/src/event_loop.rs:211
                        at /home/jwilm/code/alacritty/src/event_loop.rs:308

thread 'pty reader' panicked at 'swap_lines dst out of bounds; len=24, dst=24', src/grid.rs:163
stack backtrace:
   1:     0x556fa775059a - std::sys::imp::backtrace::tracing::imp::write::h2b860f17b6b0f511
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:42
   2:     0x556fa775590f - std::panicking::default_hook::{{closure}}::hedea7d569eb1e6b8
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:349
   3:     0x556fa775550e - std::panicking::default_hook::he87e0c76c89c52a4
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:365
   4:     0x556fa7755db7 - std::panicking::rust_panic_with_hook::h304127bde2d3d5e2
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:553
   5:     0x556fa7755c44 - std::panicking::begin_panic::h814f60faa3ce8314
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:515
   6:     0x556fa7755b69 - std::panicking::begin_panic_fmt::hf4f7d700fa077693
                        at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:499
   7:     0x556fa764a967 - alacritty::term::Term::scroll_up_relative::h162062cbd9d5d2ae
                        at /home/jwilm/code/alacritty/<panic macros>:8
                        at /home/jwilm/code/alacritty/src/grid.rs:138
                        at /home/jwilm/code/alacritty/src/term/mod.rs:594
   8:     0x556fa762fb8b - vte::Parser::perform_action::h26c5257024b70aee
                        at /home/jwilm/code/alacritty/src/term/mod.rs:810
                        at /home/jwilm/code/alacritty/src/ansi.rs:568
                        at /home/jwilm/.cargo/registry/src/github.com-1ecc6299db9ec823/vte-0.1.2/src/lib.rs:205
   9:     0x556fa764307a - <alacritty::event_loop::EventLoop<Io>>::spawn::{{closure}}::h6e25bd11b2170a6c
                        at /home/jwilm/.cargo/registry/src/github.com-1ecc6299db9ec823/vte-0.1.2/src/lib.rs:158
                        at /home/jwilm/.cargo/registry/src/github.com-1ecc6299db9ec823/vte-0.1.2/src/lib.rs:137

[rhencke]

One more to add. I couldn't find an open issue for this one:

Commit: 2fa271419c4765f7758dcf336fe0b913c12c18a6

thread 'pty reader' panicked at 'attempt to subtract with overflow', src/index.rs:168
stack backtrace:
   1:        0x102beae9a - std::sys::imp::backtrace::tracing::imp::write::h1461f67be4bf68a9
   2:        0x102bed23f - std::panicking::default_hook::{{closure}}::h6dba65b2b498d274
   3:        0x102becee7 - std::panicking::default_hook::ha8ecbcff1f59e805
   4:        0x102bed706 - std::panicking::rust_panic_with_hook::h5ceed7bd7aef311a
   5:        0x102bed554 - std::panicking::begin_panic::h091a980eb2ddd29a
   6:        0x102bed4c2 - std::panicking::begin_panic_fmt::h063a49cc71e3d103
   7:        0x102bed427 - rust_begin_unwind
   8:        0x102c155e0 - core::panicking::panic_fmt::h59374b8a88ef3536
   9:        0x102c154e4 - core::panicking::panic::he4f8d5c0f01c5414
  10:        0x10292a301 - <alacritty::index::Line as core::ops::Sub>::sub::hf56240524a3b3d20
  11:        0x102958974 - alacritty::term::Term::scroll_down_relative::h17832db7c7cd0212
  12:        0x102934b06 - <alacritty::term::Term as alacritty::ansi::Handler>::insert_blank_lines::hf4bfabc4710cd1ad
  13:        0x10294e116 - <alacritty::ansi::Performer<'a, H, W> as vte::Perform>::csi_dispatch::h4ad960a650a87e60
  14:        0x1028e6990 - vte::Parser::perform_action::hae92f4f3be45f35d
  15:        0x1028e6e96 - vte::Parser::perform_state_change::hcd974f7189d6307e
  16:        0x1028e7154 - vte::Parser::advance::hfbcbd9a431c54361
  17:        0x1029566dc - alacritty::ansi::Processor::advance::h8aa55517e89b95a8
  18:        0x102922fa1 - <alacritty::event_loop::EventLoop<Io>>::pty_read::he09815a6e7f0c6c5
  19:        0x1029226df - <alacritty::event_loop::EventLoop<Io>>::spawn::{{closure}}::hc8cce598d7c221bf
  20:        0x102952784 - <std::panic::AssertUnwindSafe<F> as core::ops::FnOnce<()>>::call_once::he8d9ee1af400fb51
  21:        0x1028e65df - std::panicking::try::do_call::ha1ffc19119230164
  22:        0x102bee5da - __rust_maybe_catch_panic
  23:        0x1028e5beb - std::panicking::try::h1d88e2383fd5222f
  24:        0x1028e3c54 - std::panic::catch_unwind::hb5a6f0073814bc71
  25:        0x1028e53ac - std::thread::Builder::spawn::{{closure}}::h0de6bfd35f37e74c
  26:        0x10291c869 - <F as alloc::boxed::FnBox<A>>::call_box::h7878f3467aa35fcc
  27:        0x102bec914 - std::sys::imp::thread::Thread::new::thread_start::haeb202749da670ee
  28:     0x7fff9f33caaa - _pthread_body
  29:     0x7fff9f33c9f6 - _pthread_start