Messages in this thread | | | Date | Tue, 13 May 2008 11:05:09 -0700 | From | Greg KH <> | Subject | Re: [stable] [PATCH] file descriptor leak in sys_pipe |
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On Mon, May 05, 2008 at 07:34:25PM -0700, Andrew Morton wrote: > On Mon, 5 May 2008 05:21:57 -0400 Ulrich Drepper <drepper@redhat.com> wrote: > > > DM <dm.n9107@gmail.com> wrote: > > > I realize this code is old, but wouldn't file descriptors leak if > > > copy_to_user fails? > > > > I think you're right. The following should patch it for the remaining > > C implementations which need that kind of patch. > > > > > > Signed-off-by: Ulrich Drepper <drepper@redhat.com> > > > > diff --git a/arch/cris/kernel/sys_cris.c b/arch/cris/kernel/sys_cris.c > > index 8b99841..d124066 100644 > > --- a/arch/cris/kernel/sys_cris.c > > +++ b/arch/cris/kernel/sys_cris.c > > @@ -40,8 +40,11 @@ asmlinkage int sys_pipe(unsigned long __user * fildes) > > error = do_pipe(fd); > > unlock_kernel(); > > if (!error) { > > - if (copy_to_user(fildes, fd, 2*sizeof(int))) > > + if (copy_to_user(fildes, fd, 2*sizeof(int))) { > > + sys_close(fd[0]); > > + sys_close(fd[1]); > > error = -EFAULT; > > + } > > } > > return error; > > } > > diff --git a/arch/m32r/kernel/sys_m32r.c b/arch/m32r/kernel/sys_m32r.c > > index 6d7a80f..319c797 100644 > > --- a/arch/m32r/kernel/sys_m32r.c > > +++ b/arch/m32r/kernel/sys_m32r.c > > @@ -90,8 +90,11 @@ sys_pipe(unsigned long r0, unsigned long r1, unsigned long r2, > > > > error = do_pipe(fd); > > if (!error) { > > - if (copy_to_user((void __user *)r0, fd, 2*sizeof(int))) > > + if (copy_to_user((void __user *)r0, fd, 2*sizeof(int))) { > > + sys_close(fd[0]); > > + sys_close(fd[1]); > > error = -EFAULT; > > + } > > } > > return error; > > } > > diff --git a/fs/pipe.c b/fs/pipe.c > > index 3499f9f..ec228bc 100644 > > --- a/fs/pipe.c > > +++ b/fs/pipe.c > > @@ -17,6 +17,7 @@ > > #include <linux/highmem.h> > > #include <linux/pagemap.h> > > #include <linux/audit.h> > > +#include <linux/syscalls.h> > > > > #include <asm/uaccess.h> > > #include <asm/ioctls.h> > > @@ -1086,8 +1087,11 @@ asmlinkage long __weak sys_pipe(int __user *fildes) > > > > error = do_pipe(fd); > > if (!error) { > > - if (copy_to_user(fildes, fd, sizeof(fd))) > > + if (copy_to_user(fildes, fd, sizeof(fd))) { > > + sys_close(fd[0]); > > + sys_close(fd[1]); > > error = -EFAULT; > > + } > > } > > return error; > > } > > OK. > > Unfortunately the sys_pipe() code has changed a lot since 2.6.25 so if we > wish to backport this fix into earlier kernels, it will need to be largely > reimplemented. > > What are the implications of the bug? An errant applicaiton can exhaust > its own fd table and eventually won't be able to open more files. This > gets fixed up when the application exits. I don't think there are any > worse implications? > > In which case 2.6.25.x and earlier can perhaps live without the fix.
As the code is so different in 2.6.25.x, I can't see how to apply this fix there, so I'll just not worry about it for now.
thanks,
greg k-h
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