Thread (17 messages) 17 messages, 4 authors, 2015-03-01

Re: [PATCH net-next 09/10] arm64: unexport set_memory_ro and set_memory_rw

From: Will Deacon <hidden>
Date: 2015-02-27 19:54:43
Also in: lkml

On Fri, Feb 27, 2015 at 02:55:41PM +0000, Daniel Borkmann wrote:
quoted hunk ↗ jump to hunk
This effectively unexports set_memory_ro and set_memory_rw functions from
commit 11d91a770f1f ("arm64: Add CONFIG_DEBUG_SET_MODULE_RONX support").

No module user of those is in mainline kernel and we explicitly do not want
modules to use these functions, as they i.e. protect eBPF (interpreted and
JIT'ed) images from malicious modifications or bugs.

Outside of eBPF scope, I believe also other set_memory_* functions should
be unexported on arm64 for modules.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Laura Abbott <redacted>
Cc: Will Deacon <redacted>
Cc: linux-kernel@vger.kernel.org
Acked-by: Alexei Starovoitov <redacted>
---
 arch/arm64/mm/pageattr.c | 2 --
 1 file changed, 2 deletions(-)
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index bb0ea94..8659357 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -70,7 +70,6 @@ int set_memory_ro(unsigned long addr, int numpages)
 					__pgprot(PTE_RDONLY),
 					__pgprot(PTE_WRITE));
 }
-EXPORT_SYMBOL_GPL(set_memory_ro);
 
 int set_memory_rw(unsigned long addr, int numpages)
 {
@@ -78,7 +77,6 @@ int set_memory_rw(unsigned long addr, int numpages)
 					__pgprot(PTE_WRITE),
 					__pgprot(PTE_RDONLY));
 }
-EXPORT_SYMBOL_GPL(set_memory_rw);
 
 int set_memory_nx(unsigned long addr, int numpages)
 {
Looks good to me. Can this be applied independently, or does it need to
remain part of your series?

Will
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