On Thu, 2014-04-10 at 10:37 +0200, Pavel Reichl wrote:
> On Wed, 2014-04-09 at 21:16 +0200, Sumit Bose wrote:
> > On Wed, Apr 09, 2014 at 05:22:16PM +0200, Pavel Reichl wrote:
> > > On Tue, 2014-04-08 at 13:23 +0200, Lukas Slebodnik wrote:
> > > > On (08/04/14 13:00), Sumit Bose wrote:
> > > > >On Mon, Apr 07, 2014 at 06:13:53PM +0200, Sumit Bose wrote:
> > > > >> On Mon, Apr 07, 2014 at 02:22:04PM +0200, Pavel Reichl wrote:
> > > > >> > Hello,
> > > > >> >
> > > > >> > I noticed these two warnings in clang.
> > > > >> >
> > > > >> > It would be great if the 2nd patch could be checked by Sumit to
> > > > >> > make
> > > > >> > sure that the return value wasn't ignored on purpose.
> > > > >>
> > > > >> yes, I would prefer to ignore errors here. There might be various
> > > > >> cases
> > > > >> were we are not able to resolve a single SID but still can proceed
> > > > >> with
> > > > >> the others.
> > > > >>
> > > > >> The first patch looks good, I'll run some tests and will give my
> > > > >> results
> > > > >> later.
> > > > >
> > > > >ACK to the first patch.
> > > > >
> > > > >bye,
> > > > >Sumit
> > > > >
> > > > Not all return point from function pac_lookup_sids_done were converted
> > > > using goto.
> > > >
> > > > --
> > > > 305- } else if (msg->count > 1) {
> > > > 306- DEBUG(SSSDBG_CRIT_FAILURE, "More then one result
> > > > returned " \
> > > > 307- "for SID [%s].\n",
> > > > 308- entries[c].key.str);
> > > > 309- talloc_free(msg);
> > > > 310: pac_cmd_done(cctx, EINVAL);
> > > > 311- return;
> > > > ^^^^^^^
> > > > here
> > > > 312- }
> > > > 313-
> > > > 314- id = ldb_msg_find_attr_as_uint64(msg->msgs[0],
> > > > 315- SYSDB_UIDNUM, 0);
> > > > --
> > > >
> > > > LS
> > > > _______________________________________________
> > > > sssd-devel mailing list
> > > > sssd-devel@lists.fedorahosted.org
> > > > https://lists.fedorahosted.org/mailman/listinfo/sssd-devel
> > >
> > > Thank you Lukas for your input. You complicated the situation one more
> > > time. :-)
> > >
> > > I had more careful look on the code and I found several places that
> > > seems troublesome to me:
> >
> > no, if you add a bit of more code:
> >
> > static errno_t pac_resolve_sids_next(struct pac_req_ctx *pr_ctx)
> > [snip]
> > req = pac_lookup_sids_send(pr_ctx, pr_ctx->cctx->ev, pr_ctx,
> > pr_ctx->pac_ctx, pr_ctx->sid_table);
> > if (req == NULL) {
> > DEBUG(SSSDBG_OP_FAILURE, "pac_lookup_sids_send failed.\n");
> > return ENOMEM;
> > }
> >
> > tevent_req_set_callback(req, pac_lookup_sids_done, pr_ctx);
> >
> > you can see that req is allocated on pr_ctx, i.e. req is a child of
> > pr_ctx. Freeing req does not free pr_ctx (but freeing pr_ctx would free
> > req as well). The hierarchy in the struct is a different one than in the
> > talloc tree.
> >
> > >
> > > > static void pac_lookup_sids_done(struct tevent_req *req)
> > > > {
> > > > struct pac_req_ctx *pr_ctx = tevent_req_callback_data(req, struct
> > > > pac_req_ctx);
> > > > struct cli_ctx *cctx = pr_ctx->cctx;
> > > >
> > > > [snip]
> > > >
> > > > ret = pac_lookup_sids_recv(req);
> > > > talloc_zfree(req);
> > > >
> > > > [snip]
> > > > ret = hash_entries(pr_ctx->sid_table, &count, &entries);
> > >
> > > Is this use of pr_ctx->sid use-after-free bug as it was allocated in req
> > > which was already freed?
> > >
> > >
> > > > talloc_free(pr_ctx);
> > > > pac_cmd_done(cctx, ret);
> > >
> > > cctx points to pr_ctx->cctx, but pr_ctx is freed before call of
> > > pac_cmd_done(cctx, ret) - use-after-free?
> >
> > same here:
> >
> > static errno_t pac_add_pac_user(struct cli_ctx *cctx)
> > [snip]
> > pr_ctx = talloc_zero(cctx, struct pac_req_ctx);
> >
> > pt_ctx is a child of cctx talloc-wise.
> >
> > HTH
> >
> > bye,
> > Sumit
> > >
> > > I don't feel confident enough to make any changes here without approval
> > > of somebody more acquainted with this code.
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > sssd-devel mailing list
> > > sssd-devel@lists.fedorahosted.org
> > > https://lists.fedorahosted.org/mailman/listinfo/sssd-devel
> > _______________________________________________
> > sssd-devel mailing list
> > sssd-devel@lists.fedorahosted.org
> > https://lists.fedorahosted.org/mailman/listinfo/sssd-devel
>
> Hello Sumit, thank you for explaining it to me - lesson learned here.
>
> Lukas, would attached patch work better for you?
>
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Hello,
Lukas, do you like this version of the patch or shall we go with
previous version of patch, which is already ACKed by Sumit?
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