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[99.254.144.39]) by smtp.gmail.com with ESMTPSA id a22-20020a05620a16d600b007671678e31fsm1800467qkn.86.2023.07.07.06.14.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Jul 2023 06:14:17 -0700 (PDT) Date: Fri, 7 Jul 2023 09:14:14 -0400 From: Peter Xu To: Axel Rasmussen Cc: Alexander Viro , Andrew Morton , Brian Geffon , Christian Brauner , David Hildenbrand , Gaosheng Cui , Huang Ying , Hugh Dickins , James Houghton , "Jan Alexander Steffens (heftig)" , Jiaqi Yan , Jonathan Corbet , Kefeng Wang , "Liam R. Howlett" , Miaohe Lin , Mike Kravetz , "Mike Rapoport (IBM)" , Muchun Song , Nadav Amit , Naoya Horiguchi , Ryan Roberts , Shuah Khan , Suleiman Souhlal , Suren Baghdasaryan , "T.J. Alumbaugh" , Yu Zhao , ZhangPeng , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v3 2/8] mm: userfaultfd: check for start + len overflow in validate_range Message-ID: References: <20230706225037.1164380-1-axelrasmussen@google.com> <20230706225037.1164380-3-axelrasmussen@google.com> MIME-Version: 1.0 In-Reply-To: <20230706225037.1164380-3-axelrasmussen@google.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Queue-Id: 131E91C0018 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: pm8kdhw5taqaqycchdgp8db1ikcs41wx X-HE-Tag: 1688735659-312905 X-HE-Meta: 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 wZfjHkGT pGtyTYLYShWf+1M6kxwWTL+PPfQgP09ogI1/a20QcXN+tKuw8id9v0Nh7a1ZhHTfzphnsp1lZLE9zoaLRKFmGjau8Gp6pJJDTgsyvZpeW7+yy5Zyp6X2/dZcmxVv/uwHYwI+FDxqeHH5t6Mkt8ctX7A3xpLNVQyrcnyEzaTSuS7KzZXPFZJHUqJcCc4Y08MdI/8Oee4XY+u7H6+LLdq+IG42XpVYNCTXNvfCBfQczO0TtVGJ0sgdUTFwXu7NIGtSqyXIIREhaenbGNZQp6R5d9CvazKuFRxLhSMsXHwXhhssx+EfVdEwB+mYIqCKRJx+G6wHKtffohWN3m2k92jsIwcbjpbNx0DYAZuj8I2s1aMta1HrmplqEwpYG6Y5cmtgeLfUzBg4276vRDDS59baAcYJiHP+ariYJd4r4hsDuuyAwbgkds9mVtRWQO94nHafOj2TZnvzfCSJCtUs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Jul 06, 2023 at 03:50:30PM -0700, Axel Rasmussen wrote: > Most userfaultfd ioctls take a `start + len` range as an argument. > We have the validate_range helper to check that such ranges are valid. > However, some (but not all!) ioctls *also* check that `start + len` > doesn't wrap around (overflow). > > Just check for this in validate_range. This saves some repetitive code, > and adds the check to some ioctls which weren't bothering to check for > it before. > > Signed-off-by: Axel Rasmussen Reviewed-by: Peter Xu -- Peter Xu