[PATCH] sys_execve and sys_uselib do not call into fsnotify

[PATCH] sys_execve and sys_uselib do not call into fsnotify

[Eric Paris]

sys_execve and sys_uselib do not call into fsnotify so inotify does not get
open events for these types of syscalls.  This patch simply makes the
requisite fsnotify calls.

Signed-off-by: Eric Paris <eparis@redhat.com>
---

 fs/exec.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)


diff --git a/fs/exec.c b/fs/exec.c
index ec5df9a..cbd93b5 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -51,6 +51,7 @@
 #include <linux/audit.h>
 #include <linux/tracehook.h>
 #include <linux/kmod.h>
+#include <linux/fsnotify.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -135,6 +136,8 @@ asmlinkage long sys_uselib(const char __user * library)
 	if (IS_ERR(file))
 		goto out;
 
+	fsnotify_open(file->f_path.dentry);
+
 	error = -ENOEXEC;
 	if(file->f_op) {
 		struct linux_binfmt * fmt;
@@ -687,6 +690,8 @@ struct file *open_exec(const char *name)
 	if (IS_ERR(file))
 		return file;
 
+	fsnotify_open(file->f_path.dentry);
+
 	err = deny_write_access(file);
 	if (err) {
 		fput(file);

Re: [PATCH] sys_execve and sys_uselib do not call into fsnotify

[Frederik Deweerdt]

Hello Eric,

On Wed, Dec 17, 2008 at 01:53:20PM -0500, Eric Paris wrote:
> sys_execve and sys_uselib do not call into fsnotify so inotify does not get
> open events for these types of syscalls.  This patch simply makes the
> requisite fsnotify calls.

Just curious, isn't the fact that the open still may fail a problem?
For example, if the lib is not executable in sys_uselib or if the file
was denied write access in open_exec.

Regards,
Frederik
> 
> Signed-off-by: Eric Paris <eparis@redhat.com>
> ---
> 
>  fs/exec.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
> 
> 
> diff --git a/fs/exec.c b/fs/exec.c
> index ec5df9a..cbd93b5 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -51,6 +51,7 @@
>  #include <linux/audit.h>
>  #include <linux/tracehook.h>
>  #include <linux/kmod.h>
> +#include <linux/fsnotify.h>
>  
>  #include <asm/uaccess.h>
>  #include <asm/mmu_context.h>
> @@ -135,6 +136,8 @@ asmlinkage long sys_uselib(const char __user * library)
>  	if (IS_ERR(file))
>  		goto out;
>  
> +	fsnotify_open(file->f_path.dentry);
> +
>  	error = -ENOEXEC;
>  	if(file->f_op) {
>  		struct linux_binfmt * fmt;
> @@ -687,6 +690,8 @@ struct file *open_exec(const char *name)
>  	if (IS_ERR(file))
>  		return file;
>  
> +	fsnotify_open(file->f_path.dentry);
> +
>  	err = deny_write_access(file);
>  	if (err) {
>  		fput(file);
> 
> 
> --
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Re: [PATCH] sys_execve and sys_uselib do not call into fsnotify

[Eric Paris]

On Wed, 2008-12-17 at 20:04 +0100, Frederik Deweerdt wrote:
> Hello Eric,
> 
> On Wed, Dec 17, 2008 at 01:53:20PM -0500, Eric Paris wrote:
> > sys_execve and sys_uselib do not call into fsnotify so inotify does not get
> > open events for these types of syscalls.  This patch simply makes the
> > requisite fsnotify calls.
> 
> Just curious, isn't the fact that the open still may fail a problem?
> For example, if the lib is not executable in sys_uselib or if the file
> was denied write access in open_exec.

I could be convinced to change it but like what I have.  At this point
the file is open.  If it fails after this we are going to call fput()
which calls __fput() which calls fsnotify_close().  Seemed odd to leave
a close without an open (although that's what we have today.)

This doesn't mean the syscall was successful, but the file was opened,
and it will be closed....

-Eric

Re: [PATCH] sys_execve and sys_uselib do not call into fsnotify

[Frederik Deweerdt]

On Wed, Dec 17, 2008 at 02:22:21PM -0500, Eric Paris wrote:
> On Wed, 2008-12-17 at 20:04 +0100, Frederik Deweerdt wrote:
> > Just curious, isn't the fact that the open still may fail a problem?
> > For example, if the lib is not executable in sys_uselib or if the file
> > was denied write access in open_exec.
> 
> I could be convinced to change it but like what I have.  At this point
> the file is open.  If it fails after this we are going to call fput()
> which calls __fput() which calls fsnotify_close().  Seemed odd to leave
> a close without an open (although that's what we have today.)
> 
> This doesn't mean the syscall was successful, but the file was opened,
> and it will be closed....
OK, thanks for clarifying,

Frederik

Re: [PATCH] sys_execve and sys_uselib do not call into fsnotify

[Andrew Morton]

On Wed, 17 Dec 2008 13:53:20 -0500
Eric Paris <eparis@redhat.com> wrote:

> sys_execve and sys_uselib do not call into fsnotify so inotify does not get
> open events for these types of syscalls.  This patch simply makes the
> requisite fsnotify calls.

These two functions are grovelling around in pretty low-level fs
operations.  One wonders whether they could be converted (ie: cleaned
up) to use do_sys_open() or some other such higher-level thing.

That way, this fsnotify bug would be magically fixed, too.

Re: [PATCH] sys_execve and sys_uselib do not call into fsnotify

[KOSAKI Motohiro]

> sys_execve and sys_uselib do not call into fsnotify so inotify does not get
> open events for these types of syscalls.  This patch simply makes the
> requisite fsnotify calls.
> 
> Signed-off-by: Eric Paris <eparis@redhat.com>

I hope append your latter explain into the patch description.

> I could be convinced to change it but like what I have.  At this point
> the file is open.  If it fails after this we are going to call fput()
> which calls __fput() which calls fsnotify_close().  Seemed odd to leave
> a close without an open (although that's what we have today.)
> 
> This doesn't mean the syscall was successful, but the file was opened,
> and it will be closed....

I think open/close pairing is important thing to this patch.


Otherthings, looks good to me. very thanks.
	Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

Re: [PATCH] sys_execve and sys_uselib do not call into fsnotify

[KOSAKI Motohiro]

> On Wed, 17 Dec 2008 13:53:20 -0500
> Eric Paris <eparis@redhat.com> wrote:
> 
> > sys_execve and sys_uselib do not call into fsnotify so inotify does not get
> > open events for these types of syscalls.  This patch simply makes the
> > requisite fsnotify calls.
> 
> These two functions are grovelling around in pretty low-level fs
> operations.  One wonders whether they could be converted (ie: cleaned
> up) to use do_sys_open() or some other such higher-level thing.
> 
> That way, this fsnotify bug would be magically fixed, too.

hmm..

In current implementaion, do_sys_open() call fd_install().
then, it cause /proc/{pid}/fd entry change. iow, compatibility break.

Yup, it is fixable. but I think Eric's implementation is simpler.