KDevelop - Attach debugger to a running process
jdhayes.linux at gmail.com
Tue Apr 7 14:52:05 BST 2020
On 4/7/20 8:27 AM, David Redondo wrote:
> Hi John,
> yes that's a kernel level setting. Probably depending on the distribution you
> are using. On my system (KDE Neon) /etc/sysctl.d/10-ptrace.conf reads:
> # The PTRACE system is used for debugging. With it, a single user process
> # can attach to any other dumpable process owned by the same user. In the
> # case of malicious software, it is possible to use PTRACE to access
> # credentials that exist in memory (re-using existing SSH connections,
> # extracting GPG agent information, etc).
> # A PTRACE scope of "0" is the more permissive mode. A scope of "1" limits
> # PTRACE only to direct child processes (e.g. "gdb name-of-program" and
> # "strace -f name-of-program" work, but gdb's "attach" and "strace -fp $PID"
> # do not). The PTRACE scope is ignored when a user has CAP_SYS_PTRACE, so
> # "sudo strace -fp $PID" will work as before. For more details see:
> # https://wiki.ubuntu.com/SecurityTeam/Roadmap/KernelHardening#ptrace
> # For applications launching crash handlers that need PTRACE, exceptions can
> # be registered by the debugee by declaring in the segfault handler
> # specifically which process will be using PTRACE on the debugee:
> # prctl(PR_SET_PTRACER, debugger_pid, 0, 0, 0);
> # In general, PTRACE is not needed for the average running Ubuntu system.
> # To that end, the default is to set the PTRACE scope to "1". This value
> # may not be appropriate for developers or servers with only admin accounts.
> Am Montag, 6. April 2020, 18:55:25 CEST schrieb John Hayes:
>> Aleix, Sven,
On 4/7/20 8:39 AM, Jonathan Verner wrote:
> the problem is that on most distributions, attaching a debugger to a running
> process is not allowed by default. See, e.g., https://stackoverflow.com/
> As per the stackoverflow question, this can be solved by running
> $ echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
> or editing `/etc/sysctl.d/10-ptrace.conf`
> It seems a good idea to mention this in the documentation. Perhaps kdevelop
> could also provide a more userfriendly message...
> On pondělí 6. dubna 2020 18:55:25 CEST John Hayes wrote:
>> Aleix, Sven,
>> Could you clarify the use of the Attach the Debugger to a running
>> Process? I am working on that section in the KDevelop5 manual and I can
>> attach to a running project with Heaptrack, but not with gdb or lldb.
>> When I try with either debugger I get:
>> ptrace: Operation not permitted.
>> Am I doing something wrong, or is this due to linux kernel changes?
Thanks guys, this looks like it will help me move forward on the manual.
It definitely needs to be mentioned in the manual to alleviate
frustration and additional questions.
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