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[47.55.120.4]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8b26b597c63sm54782485a.58.2025.11.08.16.22.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 08 Nov 2025 16:22:08 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vHtC3-00000008XBA-3FNb; Sat, 08 Nov 2025 20:22:07 -0400 Date: Sat, 8 Nov 2025 20:22:07 -0400 From: Jason Gunthorpe To: Kriish Sharma Cc: Leon Romanovsky , Vlad Dumitrescu , Parav Pandit , Edward Srouji , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+938fcd548c303fe33c1a@syzkaller.appspotmail.com Subject: Re: [PATCH v2] RDMA/core: Check for missing DGID attribute in ib_nl_is_good_ip_resp() Message-ID: <20251109002207.GF1859178@ziepe.ca> References: <20251108034336.2100529-1-kriish.sharma2006@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251108034336.2100529-1-kriish.sharma2006@gmail.com> On Sat, Nov 08, 2025 at 03:43:36AM +0000, Kriish Sharma wrote: > KMSAN reported a use of uninitialized memory in hex_byte_pack() > via ip6_string() when printing %pI6 from ib_nl_handle_ip_res_resp(). > Previously, ib_nl_process_good_ip_rsep() used the 'gid' without > verifying that the LS_NLA_TYPE_DGID attribute was present. > > This patch adds a check for the DGID attribute in ib_nl_is_good_ip_resp(), > returning false if it is missing. This prevents uninitialized memory > usage downstream in ib_nl_process_good_ip_rsep(). > > Suggested-by: Vlad Dumitrescu > Reported-by: syzbot+938fcd548c303fe33c1a@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=938fcd548c303fe33c1a > Fixes: ae43f8286730 ("IB/core: Add IP to GID netlink offload") > Signed-off-by: Kriish Sharma > --- > v2: > - Added check for LS_NLA_TYPE_DGID in ib_nl_is_good_ip_resp() to > avoid uninitialized 'gid' usage, as suggested by Vlad Dumitrescu. > > v1: https://lore.kernel.org/all/20251107041002.2091584-1-kriish.sharma2006@gmail.com > > drivers/infiniband/core/addr.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c > index 61596cda2b65..dde9114fe6a1 100644 > --- a/drivers/infiniband/core/addr.c > +++ b/drivers/infiniband/core/addr.c > @@ -93,13 +93,16 @@ static inline bool ib_nl_is_good_ip_resp(const struct nlmsghdr *nlh) > if (ret) > return false; > > + if (!tb[LS_NLA_TYPE_DGID]) > + return false; > + > return true; > } > > static void ib_nl_process_good_ip_rsep(const struct nlmsghdr *nlh) > { > const struct nlattr *head, *curr; > - union ib_gid gid; > + union ib_gid gid = {}; Let's drop this. Looking at the whole flow, it looks like it is not using nla_parse_deprecated properly.. I think it should look like this which will fix the issue and make it run faster: diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c index 61596cda2b65f3..35ba852a172aad 100644 --- a/drivers/infiniband/core/addr.c +++ b/drivers/infiniband/core/addr.c @@ -80,37 +80,25 @@ static const struct nla_policy ib_nl_addr_policy[LS_NLA_TYPE_MAX] = { .min = sizeof(struct rdma_nla_ls_gid)}, }; -static inline bool ib_nl_is_good_ip_resp(const struct nlmsghdr *nlh) +static void ib_nl_process_ip_rsep(const struct nlmsghdr *nlh) { struct nlattr *tb[LS_NLA_TYPE_MAX] = {}; + union ib_gid gid; + struct addr_req *req; + int found = 0; int ret; if (nlh->nlmsg_flags & RDMA_NL_LS_F_ERR) - return false; + return; ret = nla_parse_deprecated(tb, LS_NLA_TYPE_MAX - 1, nlmsg_data(nlh), nlmsg_len(nlh), ib_nl_addr_policy, NULL); if (ret) - return false; + return; - return true; -} - -static void ib_nl_process_good_ip_rsep(const struct nlmsghdr *nlh) -{ - const struct nlattr *head, *curr; - union ib_gid gid; - struct addr_req *req; - int len, rem; - int found = 0; - - head = (const struct nlattr *)nlmsg_data(nlh); - len = nlmsg_len(nlh); - - nla_for_each_attr(curr, head, len, rem) { - if (curr->nla_type == LS_NLA_TYPE_DGID) - memcpy(&gid, nla_data(curr), nla_len(curr)); - } + if (!tb[LS_NLA_TYPE_DGID]) + return; + memcpy(&gid, nla_data(tb[LS_NLA_TYPE_DGID]), sizeof(gid)); spin_lock_bh(&lock); list_for_each_entry(req, &req_list, list) { @@ -137,8 +125,7 @@ int ib_nl_handle_ip_res_resp(struct sk_buff *skb, !(NETLINK_CB(skb).sk)) return -EPERM; - if (ib_nl_is_good_ip_resp(nlh)) - ib_nl_process_good_ip_rsep(nlh); + ib_nl_process_ip_rsep(nlh); return 0; }