On Mon, Jan 29, 2007 at 12:33:28PM +0100, Heiko Carstens wrote:
> On Wed, Jan 24, 2007 at 01:09:18AM -0800, [EMAIL PROTECTED] wrote:
> > mm-search_binary_handler-mem-limit-fix.patch
> > From: Dmitriy Monakhov <[EMAIL PROTECTED]>
> >
> > The function changes mem limit to USER_DS before possible modprobe, but
> > never restored it again.
> >
> > Signed-off-by: Dmitriy Monakhov <[EMAIL PROTECTED]>
> > Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
> > fs/exec.c | 10 +++++++---
> > 1 file changed, 7 insertions(+), 3 deletions(-)
> >
> > diff -puN fs/exec.c~mm-search_binary_handler-mem-limit-fix fs/exec.c
> > --- a/fs/exec.c~mm-search_binary_handler-mem-limit-fix
> > +++ a/fs/exec.c
> > @@ -1018,6 +1018,7 @@ int search_binary_handler(struct linux_b
> > {
> > int try,retval;
> > struct linux_binfmt *fmt;
> > + mm_segment_t oldfs;
> > #ifdef __alpha__
> > /* handle /sbin/loader.. */
> > {
> > @@ -1059,11 +1060,12 @@ int search_binary_handler(struct linux_b
> >
> > /* kernel module loader fixup */
> > /* so we don't try to load run modprobe in kernel space. */
> > + oldfs = get_fs();
> > set_fs(USER_DS);
> >
> > retval = audit_bprm(bprm);
> > if (retval)
> > - return retval;
> > + goto out;
> >
> > retval = -ENOENT;
> > for (try=0; try<2; try++) {
> > @@ -1084,7 +1086,7 @@ int search_binary_handler(struct linux_b
> > bprm->file = NULL;
> > current->did_exec = 1;
> > proc_exec_connector(current);
> > - return retval;
> > + goto out;
> > }
> > read_lock(&binfmt_lock);
> > put_binfmt(fmt);
> > @@ -1092,7 +1094,7 @@ int search_binary_handler(struct linux_b
> > break;
> > if (!bprm->file) {
> > read_unlock(&binfmt_lock);
> > - return retval;
> > + goto out;
> > }
> > }
> > read_unlock(&binfmt_lock);
> > @@ -1110,6 +1112,8 @@ int search_binary_handler(struct linux_b
> > #endif
> > }
> > }
> > +out:
> > + set_fs(oldfs);
> > return retval;
> > }
This is broken. This is the only place in kernel that sets fs to USER_DS
for a new process. With this patch we could as well get rid of USER_DS and
all the address space checkings.
Besides that it breaks architectures with distinct physical address spaces.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
