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authorChristophe Leroy <christophe.leroy@csgroup.eu>2022-02-15 13:41:06 +0100
committerMichael Ellerman <mpe@ellerman.id.au>2022-02-16 23:25:12 +1100
commitb64913394f123e819bffabc79a0e48f98e78dc5d (patch)
tree6bdf27b3d9814cf55f96d62d92731d04857aad60 /kernel/extable.c
parent69b420ed8fd3917ac7073256b4929aa246b6fe31 (diff)
lkdtm: Really write into kernel text in WRITE_KERN
WRITE_KERN is supposed to overwrite some kernel text, namely do_overwritten() function. But at the time being it overwrites do_overwritten() function descriptor, not function text. Fix it by dereferencing the function descriptor to obtain function text pointer. Export dereference_function_descriptor() for when LKDTM is built as a module. And make do_overwritten() noinline so that it is really do_overwritten() which is called by lkdtm_WRITE_KERN(). Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/31e58eaffb5bc51c07d8d4891d1982100ade8cfc.1644928018.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'kernel/extable.c')
-rw-r--r--kernel/extable.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/extable.c b/kernel/extable.c
index 394c39b86e38..bda5e9761541 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -149,6 +149,7 @@ void *dereference_function_descriptor(void *ptr)
ptr = p;
return ptr;
}
+EXPORT_SYMBOL_GPL(dereference_function_descriptor);
void *dereference_kernel_function_descriptor(void *ptr)
{