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Sat, 06 Jun 2020 15:16:14 +0200 From: Laurent Vivier To: qemu-devel@nongnu.org Subject: [PULL v2 05/19] linux-user/mmap.c: fix integer underflow in target_mremap Date: Sat, 6 Jun 2020 15:15:53 +0200 Message-Id: <20200606131607.1250819-6-laurent@vivier.eu> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200606131607.1250819-1-laurent@vivier.eu> References: <20200606131607.1250819-1-laurent@vivier.eu> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:5vJbdaOyDOX3IMuwj7hoM3dwXxGnuZNYnT2XOSsk1C9ZXpOPz9M FCbrpW+c9RRCHL9YsReuoWlNznlvnesTC/otnrfqiPD2QMO2m+sehww62L8fdXlyeEAV3dc agNzoqwe8i7NNkpXwuOBeTGpJpfjQJYUdrf/GZTZdL2ji+oJWezmj12fsAx+5RMl9N9U3VF +Ajpgr+SPeR4mab4cwv8g== X-UI-Out-Filterresults: notjunk:1;V03:K0:fsqNGXrgIQs=:NH0NKH2RETzBlgDmx00wVf DuxFiBNe2ZWOzxk+T67dNB+XilJGRAtjTxN8R/tQdsmBFjvQiPL0fcd1vxJClDH+XdCbeKaVB VQyjC8GDZHcc4069n5F8t71fmwSw0Il4eJFJ9PSEMX0yBxUUiqfbDMDy3CEz/rLQAvrjykxiP NamrY6YNL7mdn4LqDYo5mjbCJAzv7zy6F+IdF/QdpFHd9+rN7UkQasf3m73rUKUgjmlPP7Ow3 QhiegWrm7fJnn8g9h5gr7Pun6ifBOBRgmskoDaJXkNhRmyAneoxQf8ZqvBlaOSAoB+8K7YyU/ QGryAPFlnDr3baw3GAXrRN05eUcBx88+A7N1yQY5f0EhVbO18sLS/xzaqG9vAFaOi5cQBdYOP 5ImU7TwyRahuHdSkvG85MF65JknkomtAVfPMBqt3tDbI8RRDIOBo/4q8XJYqY7xvlufoxDszq EC8pWK6hErcoxmYufuwDrNgFvDi5ut13fpdVMz5Hcu8YVbLN7gd32pwmjr1oysvIGzdwzsbYX BbzCVDQLpFHWjrhog8NgmsfsySTEaLQlicjq+9KPnJ02u7mtmrwZN4xJgDLjUtOUq2+ewEuJA /9OGAsm2Tkjn8XNWVEP0mUHhm/YuddKK1agXsXzxT92u7kBtMnfVhePEkHQPKC11w6Gnd3lwr rNwEl2HOkyOGdgCNJ6qoZwPUXNTXt3TJ81RRtIaz0ThuYhajZK+qEWuVW+TBhfV0zuKUtOanU SIBCkt0dq0LdusPrx2135+1gCf0tbY28Vm4mVyh7XBbe/JAjJHiJGLTgSO+4z7DqJ6ejN8ABV h1AMKv9HEitlNRsxbMxY8qaKYXX6sy6/qIqRHdtZYGyceP9RMlj0AN4RR01UDUksc+kmxMC Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: none client-ip=212.227.126.133; envelope-from=laurent@vivier.eu; helo=mout.kundenserver.de X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/06 09:16:19 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Riku Voipio , Jonathan Marler , Laurent Vivier Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" From: Jonathan Marler Fixes: https://bugs.launchpad.net/bugs/1876373 This code path in mmap occurs when a page size is decreased with mremap. W= hen a section of pages is shrunk, qemu calls mmap_reserve on the pages that= were released. However, it has the diff operation reversed, subtracting t= he larger old_size from the smaller new_size. Instead, it should be subtra= cting the smaller new_size from the larger old_size. You can also see in t= he previous line of the change that this mmap_reserve call only occurs when= old_size > new_size. Bug: https://bugs.launchpad.net/qemu/+bug/1876373 Signed-off-by: Jonathan Marler Reviewded-by: Laurent Vivier Message-Id: <20200502161225.14346-1-johnnymarler@gmail.com> Signed-off-by: Laurent Vivier --- linux-user/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index e37803379747..caab62909eb1 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -708,7 +708,7 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong ol= d_size, if (prot =3D=3D 0) { host_addr =3D mremap(g2h(old_addr), old_size, new_size, flags); if (host_addr !=3D MAP_FAILED && reserved_va && old_size > new= _size) { - mmap_reserve(old_addr + old_size, new_size - old_size); + mmap_reserve(old_addr + old_size, old_size - new_size); } } else { errno =3D ENOMEM; --=20 2.26.2