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([2620:10d:c090:400::5:f77c]) by smtp.gmail.com with ESMTPSA id u17-20020aa78391000000b005dea362ed18sm14247523pfm.27.2023.03.24.12.20.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Mar 2023 12:20:13 -0700 (PDT) Message-ID: Date: Fri, 24 Mar 2023 12:20:11 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH bpf-next] bpf: Check IS_ERR for the bpf_map_get() return value Content-Language: en-US, en-ZW To: Martin KaFai Lau , bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@meta.com, syzbot+71ccc0fe37abb458406b@syzkaller.appspotmail.com References: <20230324184241.1387437-1-martin.lau@linux.dev> From: Kui-Feng Lee In-Reply-To: <20230324184241.1387437-1-martin.lau@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org This fix makes sense to me. Thank you for fixing this. Acked-by: Kui-Feng Lee On 3/24/23 11:42, Martin KaFai Lau wrote: > From: Martin KaFai Lau > > This patch fixes a mistake in checking NULL instead of > checking IS_ERR for the bpf_map_get() return value. > > It also fixes the return value in link_update_map() from -EINVAL > to PTR_ERR(*_map). > > Reported-by: syzbot+71ccc0fe37abb458406b@syzkaller.appspotmail.com > Fixes: 68b04864ca42 ("bpf: Create links for BPF struct_ops maps.") > Fixes: aef56f2e918b ("bpf: Update the struct_ops of a bpf_link.") > Signed-off-by: Martin KaFai Lau > --- > kernel/bpf/bpf_struct_ops.c | 4 ++-- > kernel/bpf/syscall.c | 4 ++-- > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c > index 6401deca3b56..d3f0a4825fa6 100644 > --- a/kernel/bpf/bpf_struct_ops.c > +++ b/kernel/bpf/bpf_struct_ops.c > @@ -871,8 +871,8 @@ int bpf_struct_ops_link_create(union bpf_attr *attr) > int err; > > map = bpf_map_get(attr->link_create.map_fd); > - if (!map) > - return -EINVAL; > + if (IS_ERR(map)) > + return PTR_ERR(map); > > st_map = (struct bpf_struct_ops_map *)map; > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index b4d758fa5981..a09597c95029 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -4689,12 +4689,12 @@ static int link_update_map(struct bpf_link *link, union bpf_attr *attr) > > new_map = bpf_map_get(attr->link_update.new_map_fd); > if (IS_ERR(new_map)) > - return -EINVAL; > + return PTR_ERR(new_map); > > if (attr->link_update.flags & BPF_F_REPLACE) { > old_map = bpf_map_get(attr->link_update.old_map_fd); > if (IS_ERR(old_map)) { > - ret = -EINVAL; > + ret = PTR_ERR(old_map); > goto out_put; > } > } else if (attr->link_update.old_map_fd) {