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[74.87.59.234]) by smtp.gmail.com with ESMTPSA id x4-20020a170902ea8400b0019a5f1410d1sm5299634plb.43.2023.02.11.15.09.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 11 Feb 2023 15:09:26 -0800 (PST) Message-ID: <3277df5d-7c6a-d33a-1cab-6506742c66db@linaro.org> Date: Sat, 11 Feb 2023 13:09:22 -1000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH 7/9] bsd-user: do_freebsd_sysctl helper for sysctl(2) Content-Language: en-US To: Warner Losh , qemu-devel@nongnu.org Cc: Thomas Huth , Kyle Evans , f4bug@amsat.org, =?UTF-8?Q?Alex_Benn=c3=a9e?= , Paolo Bonzini , Juergen Lock , Stacey Son References: <20230210231829.39476-1-imp@bsdimp.com> <20230210231829.39476-8-imp@bsdimp.com> From: Richard Henderson In-Reply-To: <20230210231829.39476-8-imp@bsdimp.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::62c; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x62c.google.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-1.148, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 2/10/23 13:18, Warner Losh wrote: > +abi_long do_freebsd_sysctl(CPUArchState *env, abi_ulong namep, int32_t namelen, > + abi_ulong oldp, abi_ulong oldlenp, abi_ulong newp, abi_ulong newlen) > +{ > + abi_long ret; > + void *hnamep, *holdp = NULL, *hnewp = NULL; > + size_t holdlen; > + abi_ulong oldlen = 0; > + int32_t *snamep = g_malloc(sizeof(int32_t) * namelen), *p, *q, i; > + > + if (oldlenp) { > + if (get_user_ual(oldlen, oldlenp)) { > + return -TARGET_EFAULT; > + } > + } You need to check for write early. Either access_ok, or lock_user. > + for (p = hnamep, q = snamep, i = 0; i < namelen; p++, i++) { > + *q++ = tswap32(*p); > + } Why the inconsistent increments? > + unlock_user(holdp, oldp, holdlen); Usually we don't want writeback on error. r~