[lldb-dev] [Bug 42471] New: GDB remote protocol 'A' packet format is not spec-compliant

[via lldb-dev]

https://bugs.llvm.org/show_bug.cgi?id=42471

            Bug ID: 42471
           Summary: GDB remote protocol 'A' packet format is not
                    spec-compliant
           Product: lldb
           Version: 8.0
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: All Bugs
          Assignee: lldb-dev at lists.llvm.org
          Reporter: spmichaels.work at gmail.com
                CC: jdevlieghere at apple.com, llvm-bugs at lists.llvm.org

LLDB's GDB remote protocol implementation defines a parser for the 'A' packet
at tools/debugger/source/RNBRemote.cpp:1538 (i.e. RNBRemote::HandlePacket_A()).
This packet is used to pass an argv[] array to the program.

GDB's remote protocol spec defines the A packet as follows (see
(https://sourceware.org/gdb/onlinedocs/gdb/Packets.html):

---
‘A arglen,argnum,arg,…’

Initialized argv[] array passed into program. arglen specifies the number of
bytes in the hex encoded byte stream arg. See gdbserver for more details.
---

Note that `gdbserver` does not actually implement the A packet (see
https://github.com/bminor/binutils-gdb/blob/master/gdb/gdbserver/server.c), so
the note to "See gdbserver for more details" is moot.


LLDB's implementation assumes that 'arglen' and 'argnum' are base-10 unsigned
integers. However, the GDB remote protocol overview specifies that (see
https://sourceware.org/gdb/onlinedocs/gdb/Overview.html#Overview):

---
Except where otherwise noted all numbers are represented in HEX with leading
zeros suppressed.
---

Since the 'A' packet definition does not explicitly specify a base for arglen
and argnum, thesei should actually be base-16, not base-10 as they are now.

This would require changes to the two `strtoul()` calls on lines 1562 and 1574
of `RNBRemote.cpp`.

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/lldb-dev/attachments/20190701/2c5458a0/attachment.html>