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bh=4/ivNU19vgx8JM95ZcxudD+bsQ3V+RD7J/J7pfkup6o=; b=8RPdksK99rsaPALZacw8jKuxrWGK5sjIk3C7W9A+paHRrs7YTqjYsAatHKK6j5Q+PF Qy+3BcK6ynmh0Nm0g2mVkjEq2mZfjHdGX5Z8ABHXIOon7K3Q132etm+QrPzy9hqoFXzO efkZBMnd4qxhFcMtdceJu9z9T1IFVqY1KkNMU5gZWwM486uyTy1P1MB8zs5sT+i8egVM jLF604euMgrARWwn/QSO5wTql7Tr23RZHxJpKPqKvVBuV7lqjONvCPYObduWxFiZ9/Fe +QIe2EB09QtnIfA2OjxiLwbJpSyOrzaT+/PhRyGND8zKLIDsI7S4NPcZZdpM7bdRCE5t wbow== X-Gm-Message-State: AOAM5324tyU228fv3Ke4ljh5x+gwi+JEEdBGcQ6sSrPpezMXX6ssaKE8 2wGicJC706H//LVj3IhiKmCahLEOrCAxLdkru+ZC3A== X-Google-Smtp-Source: ABdhPJwBHMz+LzOFUiQTIwbzPzdvrXtTVwYQpG2iiSp91TzBtWRskcUIoeGW7uJi+Qpxvni4TX/PSl9W+KQ5xZ2gyXg= X-Received: by 2002:a05:6808:118:: with SMTP id b24mr8614615oie.0.1631550164556; Mon, 13 Sep 2021 09:22:44 -0700 (PDT) MIME-Version: 1.0 References: <20210913131113.390368911@linuxfoundation.org> <20210913131114.028340332@linuxfoundation.org> In-Reply-To: <20210913131114.028340332@linuxfoundation.org> From: Naresh Kamboju Date: Mon, 13 Sep 2021 21:52:33 +0530 Message-ID: Subject: Re: [PATCH 5.14 018/334] nbd: add the check to prevent overflow in __nbd_ioctl() To: Greg Kroah-Hartman , Nathan Chancellor , Nick Desaulniers , Baokun Li Cc: open list , linux-stable , Hulk Robot , Josef Bacik , Jens Axboe , Sasha Levin , clang-built-linux , lkft-triage@lists.linaro.org, llvm@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 13 Sept 2021 at 19:51, Greg Kroah-Hartman wrote: > > From: Baokun Li > > [ Upstream commit fad7cd3310db3099f95dd34312c77740fbc455e5 ] > > If user specify a large enough value of NBD blocks option, it may trigger > signed integer overflow which may lead to nbd->config->bytesize becomes a > large or small value, zero in particular. > > UBSAN: Undefined behaviour in drivers/block/nbd.c:325:31 > signed integer overflow: > 1024 * 4611686155866341414 cannot be represented in type 'long long int' > [...] > Call trace: > [...] > handle_overflow+0x188/0x1dc lib/ubsan.c:192 > __ubsan_handle_mul_overflow+0x34/0x44 lib/ubsan.c:213 > nbd_size_set drivers/block/nbd.c:325 [inline] > __nbd_ioctl drivers/block/nbd.c:1342 [inline] > nbd_ioctl+0x998/0xa10 drivers/block/nbd.c:1395 > __blkdev_driver_ioctl block/ioctl.c:311 [inline] > [...] > > Although it is not a big deal, still silence the UBSAN by limit > the input value. > > Reported-by: Hulk Robot > Signed-off-by: Baokun Li > Reviewed-by: Josef Bacik > Link: https://lore.kernel.org/r/20210804021212.990223-1-libaokun1@huawei.com > [axboe: dropped unlikely()] > Signed-off-by: Jens Axboe > Signed-off-by: Sasha Levin > --- > drivers/block/nbd.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c > index 19f5d5a8b16a..acf3f85bf3c7 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -1388,6 +1388,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, > unsigned int cmd, unsigned long arg) > { > struct nbd_config *config = nbd->config; > + loff_t bytesize; > > switch (cmd) { > case NBD_DISCONNECT: > @@ -1402,8 +1403,9 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, > case NBD_SET_SIZE: > return nbd_set_size(nbd, arg, config->blksize); > case NBD_SET_SIZE_BLOCKS: > - return nbd_set_size(nbd, arg * config->blksize, > - config->blksize); > + if (check_mul_overflow((loff_t)arg, config->blksize, &bytesize)) > + return -EINVAL; > + return nbd_set_size(nbd, bytesize, config->blksize); > case NBD_SET_TIMEOUT: > nbd_set_cmd_timeout(nbd, arg); > return 0; arm clang-10, clang-11, clang-12 and clang-13 builds failed. due to this commit on 5.14 and 5.13 on following configs, - footbridge_defconfig - mini2440_defconfig - s3c2410_defconfig This was already reported on the mailing list. ERROR: modpost: "__mulodi4" [drivers/block/nbd.ko] undefined! #1438 https://github.com/ClangBuiltLinux/linux/issues/1438 [PATCH 00/10] raise minimum GCC version to 5.1 https://lore.kernel.org/lkml/20210910234047.1019925-1-ndesaulniers@google.com/ linux-next: build failure while building Linus' tree https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/ Full build log, https://gitlab.com/Linaro/lkft/mirrors/stable/linux-stable-rc/-/jobs/1585407346#L1111 -- Linaro LKFT https://lkft.linaro.org