Avoid use-after-free when disabling local tracepoint #5862
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Disabling a local tracepoint while handling a different tracepoint can cause a use-after-free in exec_hooks_body in certain cases, because exec_hooks_body accessed local_hooks freed earlier in iseq_remove_local_tracepoint. Fix this by changing local_hooks in rb_iseq_struct from struct rb_hook_list_struct * to struct rb_hook_list_struct **. This allows us to set *local_hooks to NULL after freeing *local_hooks. Functions now check both local_hooks and *local_hooks, and only run hooks if both are non-NULL. Addresses use-after-free crash found while in investigating #18730.
XrXr
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`vm_trace_hook()` runs global hooks before running local hooks. Previously, we read the local hook list before running the global hooks which led to use-after-free when the global hook frees the local hook list, for example by disabling a local TracePoint. Delay local hook list loading until after running the global hooks. Issue discovered by Jeremy Evans in rubyGH-5862.
XrXr
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Apr 29, 2022
`vm_trace_hook()` runs global hooks before running local hooks. Previously, we read the local hook list before running the global hooks which led to use-after-free when the global hook frees the local hook list, for example by disabling a local TracePoint. Delay local hook list loading until after running the global hooks. Issue discovered by Jeremy Evans in rubyGH-5862.
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It seemed weird to me that adding another allocation is necessary and I debugged this down to an ordering problem in |
XrXr
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May 28, 2022
`vm_trace_hook()` runs global hooks before running local hooks. Previously, we read the local hook list before running the global hooks which led to use-after-free when a global hook frees the local hook list. A global hook can do this by disabling a local TracePoint, for example. Delay local hook list loading until after running the global hooks. Issue discovered by Jeremy Evans in rubyGH-5862. [Bug #18730]
XrXr
added a commit
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that referenced
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May 28, 2022
`vm_trace_hook()` runs global hooks before running local hooks. Previously, we read the local hook list before running the global hooks which led to use-after-free when a global hook frees the local hook list. A global hook can do this by disabling a local TracePoint, for example. Delay local hook list loading until after running the global hooks. Issue discovered by Jeremy Evans in rubyGH-5862. [Bug #18730]
XrXr
added a commit
to XrXr/ruby
that referenced
this pull request
May 28, 2022
`vm_trace_hook()` runs global hooks before running local hooks. Previously, we read the local hook list before running the global hooks which led to use-after-free when a global hook frees the local hook list. A global hook can do this by disabling a local TracePoint, for example. Delay local hook list loading until after running the global hooks. Issue discovered by Jeremy Evans in rubyGH-5862. [Bug #18730]
XrXr
added a commit
that referenced
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May 30, 2022
`vm_trace_hook()` runs global hooks before running local hooks. Previously, we read the local hook list before running the global hooks which led to use-after-free when a global hook frees the local hook list. A global hook can do this by disabling a local TracePoint, for example. Delay local hook list loading until after running the global hooks. Issue discovered by Jeremy Evans in GH-5862. [Bug #18730]
schneems
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Jul 26, 2022
`vm_trace_hook()` runs global hooks before running local hooks. Previously, we read the local hook list before running the global hooks which led to use-after-free when a global hook frees the local hook list. A global hook can do this by disabling a local TracePoint, for example. Delay local hook list loading until after running the global hooks. Issue discovered by Jeremy Evans in rubyGH-5862. [Bug #18730]
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Disabling a local tracepoint while handling a different tracepoint
can cause a use-after-free in exec_hooks_body in certain cases,
because exec_hooks_body accessed local_hooks freed earlier in
iseq_remove_local_tracepoint.
Fix this by changing local_hooks in rb_iseq_struct from
struct rb_hook_list_struct * to struct rb_hook_list_struct **.
This allows us to set *local_hooks to NULL after freeing
*local_hooks. Functions now check both local_hooks and
*local_hooks, and only run hooks if both are non-NULL.
Addresses use-after-free crash found while investigating #18730.