linux-kernel - [PATCH 2/4] debugfs: Add read-only/write-only x64 file ops

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Date:	Mon, 12 Oct 2015 18:09:10 -0700
From:	Stephen Boyd <sboyd@...eaurora.org>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	linux-kernel@...r.kernel.org,
	Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH 2/4] debugfs: Add read-only/write-only x64 file ops

There aren't any read-only or write-only x64 file ops, but there
is a caller of debugfs_create_x64() that calls it with mode equal
to S_IRUGO. This leads to the possibility of userspace modifying
the file, so let's use the newly created debugfs_create_mode()
helper here to fix this.

Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
---
 fs/debugfs/file.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 5d594efa7c93..f69d42efe4b8 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -256,6 +256,8 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
 DEFINE_SIMPLE_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
 
 DEFINE_SIMPLE_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, "0x%016llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
 
 /*
  * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
@@ -332,7 +334,8 @@ EXPORT_SYMBOL_GPL(debugfs_create_x32);
 struct dentry *debugfs_create_x64(const char *name, umode_t mode,
 				 struct dentry *parent, u64 *value)
 {
-	return debugfs_create_file(name, mode, parent, value, &fops_x64);
+	return debugfs_create_mode(name, mode, parent, value, &fops_x64,
+				   &fops_x64_ro, &fops_x64_wo);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_x64);
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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