On 01/21/2015 07:54 AM, Sabrina Dubroca wrote:
2015-01-21, 16:39:12 +0100, Thierry Reding wrote:
On Wed, Jan 21, 2015 at 10:24:11AM -0500, Paul Moore wrote:
On Wednesday, January 21, 2015 03:42:16 PM Thierry Reding wrote:
On Wed, Jan 21, 2015 at 12:05:39PM +0100, Sabrina Dubroca wrote:
2015-01-21, 04:36:38 +0000, Al Viro wrote:
On Tue, Jan 20, 2015 at 08:01:26PM -0800, Guenter Roeck wrote:
With this patch:
sys_mkdir .:40775 returned -17
sys_mkdir usr:40775 returned 0
sys_mkdir usr/lib:40775 returned 0
sys_mkdir usr/share:40755 returned 0
sys_mkdir usr/share/udhcpc:40755 returned 0
sys_mkdir usr/bin:40775 returned 0
sys_mkdir usr/sbin:40775 returned 0
sys_mkdir mnt:40775 returned 0
sys_mkdir proc:40775 returned 0
sys_mkdir root:40775 returned 0
sys_mkdir lib:40775 returned 0
sys_mkdir lib/modules:40775 returned 0
...
and the problem is fixed.
This patch also works for me.
... except that it simply confirms that something's fishy with
getname_kernel() of ->name of struct filename returned by getname().
IOW, I still do not understand the mechanism of breakage there.
I'm not so sure about that. I tried to copy name to a new string in
do_path_lookup and that didn't help.
Now, I've removed the
putname(filename);
line from do_path_lookup and I don't get the panic.
That would indicate that somehow the refcount got unbalanced. Looking
more closely it seems like the various audit_*() function do take a
reference, but maybe that's not enough.
I'm thinking the same thing and I think the problem may be that
__audit_reusename() is not bumping the filename->refcnt. Can someone who is
seeing this problem bump the refcnt in __audit_reusename()?
struct filename *
__audit_reusename(const __user char *uptr)
{
struct audit_context *context = current->audit_context;
struct audit_names *n;
list_for_each_entry(n, &context->names_list, list) {
if (!n->name)
continue;
if (n->name->uptr == uptr) {
+ n->name->refcnt++;
return n->name;
}
}
return NULL;
}
That doesn't seem to help, at least in my case.
Same here.
Well, it's probably not an audit issue. I tried audit=0 on the
commandline, and I just rebuilt a kernel with CONFIG_AUDIT=n, and it's
still panicing. This should have fixed any audit-related issue,
right?
I don't have audit enabled, so I don't think that is the problem either
(the refcount increase didn't help, and a WARN(1) added to the code
at the same location did not trigger).
Wonder if we have a use-after-free case and just have been lucky all along.
Guenter
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