On Fri, Feb 23, 2024 at 3:04 PM Mickaël Salaün <mic@xxxxxxxxxxx> wrote: > > On Fri, Feb 23, 2024 at 08:59:34PM +0100, Mickaël Salaün wrote: > > On Fri, Feb 23, 2024 at 08:05:45PM +0100, Mickaël Salaün wrote: > > > selinux_lsm_getattr() may not initialize the value's pointer in some > > > case. As for proc_pid_attr_read(), initialize this pointer to NULL in > > > selinux_getselfattr() to avoid an UAF in the kfree() call. > > > > Not UAF but NULL pointer dereference (both patches)... > > Well, that may be the result (as observed with the kfree() call), but > the cause is obviously an uninitialized pointer. Adding the SELinux list to the CC line; SELinux folks the original post is here: * https://lore.kernel.org/all/20240223190546.3329966-1-mic@xxxxxxxxxxx Thanks for finding this and testing the patch, based on our off-list discussion, do you mind if I add a Suggested-by? Looking at this a bit more I think we'll want to make a few changes to selinux_lsm_getattr() later, but this patch is a good one for stable as it not only fixes the bug, but it is a trivial one-liner with very low risk. I do think we need to tweak the commit description a bit, what do you think of the following? "selinux_getselfattr() doesn't properly initialize the string pointer it passes to selinux_lsm_getattr() which can cause a problem when an attribute hasn't been explicitly set; selinux_lsm_getattr() returns 0/success, but does not set or initialize the string label/attribute. Failure to properly initialize the string causes problems later in selinux_getselfattr() when the function attempts to kfree() the string." -- paul-moore.com
