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From:   Richard Guy Briggs <rgb@redhat.com>
To:     Linux-Audit Mailing List <linux-audit@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org
Cc:     Paul Moore <paul@paul-moore.com>,
        Eric Paris <eparis@parisplace.org>,
        Steve Grubb <sgrubb@redhat.com>,
        Richard Guy Briggs <rgb@redhat.com>, Jan Kara <jack@suse.cz>,
        Amir Goldstein <amir73il@gmail.com>
Subject: [PATCH v3 1/3] fanotify: Ensure consistent variable type for response
Date:   Mon, 16 May 2022 16:22:22 -0400
Message-Id: <b70eb9b7620fdda8c46acf055dfd518b81ae2931.1652730821.git.rgb@redhat.com>
In-Reply-To: <cover.1652730821.git.rgb@redhat.com>
References: <cover.1652730821.git.rgb@redhat.com>
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The user space API for the response variable is __u32. This patch makes
sure that the whole path through the kernel uses u32 so that there is
no sign extension or truncation of the user space response.

Suggested-by: Steve Grubb <sgrubb@redhat.com>
Link: https://lore.kernel.org/r/12617626.uLZWGnKmhe@x2
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
 fs/notify/fanotify/fanotify.h      | 2 +-
 fs/notify/fanotify/fanotify_user.c | 6 +++---
 include/linux/audit.h              | 6 +++---
 kernel/auditsc.c                   | 2 +-
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index a3d5b751cac5..d66668e06bee 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -425,7 +425,7 @@ FANOTIFY_PE(struct fanotify_event *event)
 struct fanotify_perm_event {
 	struct fanotify_event fae;
 	struct path path;
-	unsigned short response;	/* userspace answer to the event */
+	u32 response;			/* userspace answer to the event */
 	unsigned short state;		/* state of the event */
 	int fd;		/* fd we passed to userspace for this event */
 };
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 9b32b76a9c30..721e777ea90b 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -289,7 +289,7 @@ static int create_fd(struct fsnotify_group *group, struct path *path,
  */
 static void finish_permission_event(struct fsnotify_group *group,
 				    struct fanotify_perm_event *event,
-				    unsigned int response)
+				    u32 response)
 				    __releases(&group->notification_lock)
 {
 	bool destroy = false;
@@ -310,9 +310,9 @@ static int process_access_response(struct fsnotify_group *group,
 {
 	struct fanotify_perm_event *event;
 	int fd = response_struct->fd;
-	int response = response_struct->response;
+	u32 response = response_struct->response;
 
-	pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group,
+	pr_debug("%s: group=%p fd=%d response=%u\n", __func__, group,
 		 fd, response);
 	/*
 	 * make sure the response is valid, if invalid we do nothing and either
diff --git a/include/linux/audit.h b/include/linux/audit.h
index d06134ac6245..217784d602b3 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -419,7 +419,7 @@ extern void __audit_log_capset(const struct cred *new, const struct cred *old);
 extern void __audit_mmap_fd(int fd, int flags);
 extern void __audit_openat2_how(struct open_how *how);
 extern void __audit_log_kern_module(char *name);
-extern void __audit_fanotify(unsigned int response);
+extern void __audit_fanotify(u32 response);
 extern void __audit_tk_injoffset(struct timespec64 offset);
 extern void __audit_ntp_log(const struct audit_ntp_data *ad);
 extern void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
@@ -526,7 +526,7 @@ static inline void audit_log_kern_module(char *name)
 		__audit_log_kern_module(name);
 }
 
-static inline void audit_fanotify(unsigned int response)
+static inline void audit_fanotify(u32 response)
 {
 	if (!audit_dummy_context())
 		__audit_fanotify(response);
@@ -686,7 +686,7 @@ static inline void audit_log_kern_module(char *name)
 {
 }
 
-static inline void audit_fanotify(unsigned int response)
+static inline void audit_fanotify(u32 response)
 { }
 
 static inline void audit_tk_injoffset(struct timespec64 offset)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index ea2ee1181921..6973be0bf6c9 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2893,7 +2893,7 @@ void __audit_log_kern_module(char *name)
 	context->type = AUDIT_KERN_MODULE;
 }
 
-void __audit_fanotify(unsigned int response)
+void __audit_fanotify(u32 response)
 {
 	audit_log(audit_context(), GFP_KERNEL,
 		AUDIT_FANOTIFY,	"resp=%u", response);
-- 
2.27.0