linux-kernel - [PATCH] fs: Fix internal type confusion in getdents system calls

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Date:   Thu, 27 Jun 2019 11:50:58 +0200
From:   Florian Weimer <fweimer@...hat.com>
To:     linux-fsdevel@...r.kernel.org
Cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] fs: Fix internal type confusion in getdents system calls

The callback functions use a signed int type, but the callers have
only verified the value as an unsigned type.  This should be only
a cosmetic change because if the value wraps around, this error
check catches it:

	if (reclen > buf->count)
		return -EINVAL;

But it should be clearer to prevent the wrap-around.

Signed-off-by: Florian Weimer <fweimer@...hat.com>
---
 fs/readdir.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/readdir.c b/fs/readdir.c
index 2f6a4534e0df..d344061e387e 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -159,7 +159,7 @@ struct getdents_callback {
 	struct dir_context ctx;
 	struct linux_dirent __user * current_dir;
 	struct linux_dirent __user * previous;
-	int count;
+	unsigned int count;
 	int error;
 };
 
@@ -246,7 +246,7 @@ struct getdents_callback64 {
 	struct dir_context ctx;
 	struct linux_dirent64 __user * current_dir;
 	struct linux_dirent64 __user * previous;
-	int count;
+	unsigned int count;
 	int error;
 };
 
@@ -413,7 +413,7 @@ struct compat_getdents_callback {
 	struct dir_context ctx;
 	struct compat_linux_dirent __user *current_dir;
 	struct compat_linux_dirent __user *previous;
-	int count;
+	unsigned int count;
 	int error;
 };
 
-- 
2.21.0