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memfd: pass argument of memfd_fcntl as int

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The interface for fcntl expects the argument passed for the command
F_ADD_SEALS to be of type int.  The current code wrongly treats it as a
long.  In order to avoid access to undefined bits, we should explicitly
cast the argument to int.

This commit changes the signature of all the related and helper functions
so that they treat the argument as int instead of long.

Link: https://lkml.kernel.org/r/20230414152459.816046-5-Luca.Vizzarro@arm.com
Signed-off-by: Luca Vizzarro <Luca.Vizzarro@arm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Kevin Brodsky <Kevin.Brodsky@arm.com>
Cc: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Cc: Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: David Laight <David.Laight@ACULAB.com>
Cc: Mark Rutland <Mark.Rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Luca Vizzarro 2023-04-14 16:24:58 +01:00 committed by Andrew Morton
parent 7f63cf2d9b
commit f7b8f70ba4
2 changed files with 3 additions and 7 deletions
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4
include/linux/memfd.h
View File

@ -5,9 +5,9 @@
#include <linux/file.h>
#ifdef CONFIG_MEMFD_CREATE
extern long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg);
extern long memfd_fcntl(struct file *file, unsigned int cmd, unsigned int arg);
#else
static inline long memfd_fcntl(struct file *f, unsigned int c, unsigned long a)
static inline long memfd_fcntl(struct file *f, unsigned int c, unsigned int a)
{
return -EINVAL;
}

6
mm/memfd.c
View File

@ -243,16 +243,12 @@ static int memfd_get_seals(struct file *file)
return seals ? *seals : -EINVAL;
}
long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
long memfd_fcntl(struct file *file, unsigned int cmd, unsigned int arg)
{
long error;
switch (cmd) {
case F_ADD_SEALS:
/* disallow upper 32bit */
if (arg > UINT_MAX)
return -EINVAL;
error = memfd_add_seals(file, arg);
break;
case F_GET_SEALS: