[PATCH] powerpc/powernv: Make opal log only readable by root

Currently the opal log is globally readable. It is kernel policy to limit
the visibility of physical addresses / kernel pointers to root.
Given this and the fact the opal log may contain this information it would
be better to limit the readability to root.

Signed-off-by: Jordan Niethe <redacted>
---
 arch/powerpc/platforms/powernv/opal-msglog.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/powernv/opal-msglog.c b/arch/powerpc/platforms/powernv/opal-msglog.c
index acd3206dfae3..06628c71cef6 100644
--- a/arch/powerpc/platforms/powernv/opal-msglog.c
+++ b/arch/powerpc/platforms/powernv/opal-msglog.c

@@ -98,7 +98,7 @@ static ssize_t opal_msglog_read(struct file *file, struct kobject *kobj,
 }
 
 static struct bin_attribute opal_msglog_attr = {
-	.attr = {.name = "msglog", .mode = 0444},
+	.attr = {.name = "msglog", .mode = 0400},
 	.read = opal_msglog_read
 };
 

-- 
2.20.1

Jordan Niethe [off-list ref] writes:

Currently the opal log is globally readable. It is kernel policy to limit
the visibility of physical addresses / kernel pointers to root.
Given this and the fact the opal log may contain this information it would
be better to limit the readability to root.

Signed-off-by: Jordan Niethe <redacted>

Yeah, this is a really good idea.

Reviewed-by: Stewart Smith <redacted>

-- 
Stewart Smith
OPAL Architect, IBM.

On 27/2/19 2:02 pm, Jordan Niethe wrote:

Currently the opal log is globally readable. It is kernel policy to limit
the visibility of physical addresses / kernel pointers to root.
Given this and the fact the opal log may contain this information it would
be better to limit the readability to root.

Signed-off-by: Jordan Niethe <redacted>

Guess I'll have to get used to typing sudo more often. :(

Makes sense also given that we do the same thing for exports afaict.

Reviewed-by: Andrew Donnellan <redacted>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com  IBM Australia Limited

Jordan Niethe [off-list ref] writes:

Currently the opal log is globally readable. It is kernel policy to limit
the visibility of physical addresses / kernel pointers to root.
Given this and the fact the opal log may contain this information it would
be better to limit the readability to root.

Yikes, thanks for fixing that.

I'll add a Fixes: tag and Cc stable.

I also see symbol_map is 0444, I think that should be fixed too.

cheers

On Wed, 2019-02-27 at 03:02:29 UTC, Jordan Niethe wrote:

Currently the opal log is globally readable. It is kernel policy to limit
the visibility of physical addresses / kernel pointers to root.
Given this and the fact the opal log may contain this information it would
be better to limit the readability to root.

Signed-off-by: Jordan Niethe <redacted>
Reviewed-by: Stewart Smith <redacted>
Reviewed-by: Andrew Donnellan <redacted>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/7b62f9bd2246b7d3d086e571397c14ba

cheers