mirror of https://github.com/tLDP/LDP
58 lines
1.9 KiB
Plaintext
58 lines
1.9 KiB
Plaintext
The Problem with this example is, you will get unresolved symbols
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if you try to insmod it into a stock 2.6.x kernel.
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This is because the interception of system calls via sys_call_table
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is considered harmful and thus no longer supported. (since 2.5.41)
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See the thread: (pick just one)
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http://www.ussg.iu.edu/hypermail/linux/kernel/0305.0/0711.html
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http://marc.free.net.ph/message/20030505.081945.fa640369.html
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http://marc.theaimsgroup.com/?l=linux-kernel&m=105212296015799&w=2
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for why.
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To be able to get this example running with post 2.5.41 (read 2.6.x)
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kernels you must patch your kernel to export sys_call_table.
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WARNING:
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DONT TRY THIS ON PRODUCTION SYSTEMS, OR ANY OTHER SYSTEMS
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WITH VALUEABLE DATA ON IT.
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If I had to write a Configure.help entry for this patch it would
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be tagged <dangerous> and probably look like this:
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#######################################################################
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This option exports the sys_call_table, which makes it possible to
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intercept system calls. Intercepting system calls is dangerous,
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and might cause data loss or worse.
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Say Y if you want to try the included example and don't care about
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data loss and other scary stuff.
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Virtually anybody else should say N here.
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#######################################################################
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Using an old PC you don't need for anything else as a sandbox
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might be a good idea either.
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Assuming your current 2.6.x kernel tree lies under /usr/src/linux/
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(where it should not! [1] ;) the script below shows how to apply,
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compile and boot a sys_call_table exporting kernel in one go.
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This patch has been tested with 2.6.[0123], and may / may not apply
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clean / at all to other versions.
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[1] http://www.linuxmafia.com/faq/Kernel/usr-src-linux-symlink.html
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#!/bin/sh
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cp export_sys_call_table_patch_for_linux_2.6.x /usr/src/linux/
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cd /usr/src/linux/
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patch -p0 < export_sys_call_table_patch_for_linux_2.6.x
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