uprobe,bpf: Allow to change app registers from uprobe #5675
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If uprobe handler changes instruction pointer we still execute single step) or emulate the original instruction and increment the (new) ip with its length. This makes the new instruction pointer bogus and application will likely crash on illegal instruction execution. If user decided to take execution elsewhere, it makes little sense to execute the original instruction, so let's skip it. Signed-off-by: Jiri Olsa <[email protected]>
Currently uprobe (BPF_PROG_TYPE_KPROBE) program can't write to the context registers data. While this makes sense for kprobe attachments, for uprobe attachment it might make sense to be able to change user space registers to alter application execution. Since uprobe and kprobe programs share the same type (BPF_PROG_TYPE_KPROBE), we can't deny write access to context during the program load. We need to check on it during program attachment to see if it's going to be kprobe or uprobe. Storing the program's write attempt to context and checking on it during the attachment. Signed-off-by: Jiri Olsa <[email protected]>
Adding test to check we can change common register values through uprobe program. It's x86_64 specific test. Signed-off-by: Jiri Olsa <[email protected]>
Adding test to check we can change the application execution through instruction pointer change through uprobe program. It's x86_64 specific test. Signed-off-by: Jiri Olsa <[email protected]>
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Upstream branch: e8d780d |
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=987804 expired. Closing PR. |
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Pull request for series with
subject: uprobe,bpf: Allow to change app registers from uprobe
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=987804