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[66.187.233.206]) by smtp.gmail.com with ESMTPSA id a24-20020a05620a067800b0069c233fa524sm1987715qkh.1.2022.04.11.10.50.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Apr 2022 10:50:33 -0700 (PDT) From: Tom Rix To: tim@cyberelk.net, axboe@kernel.dk, nathan@kernel.org, ndesaulniers@google.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Tom Rix Subject: [PATCH v2] pcd: do not leak information in ioctl Date: Mon, 11 Apr 2022 13:50:26 -0400 Message-Id: <20220411175026.2961880-1-trix@redhat.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" clang static analysis reports this representative issue pcd.c:832:22: warning: Assigned value is garbage or undefined tochdr->cdth_trk0 =3D buffer[2]; ^ ~~~~~~~~~ If the call to pcd_atapi fails, buffer is an unknown state. Passing an unknown buffer back to the user can leak information and is a security risk. Check before returning this buffer to the user. The per-case variables cmd and buffer are common. Change their scope to function level. Change colliding parameter name cmd to request. Cleanup whitespace Additionally initialize the buffer to zero. This problem can be seen in the 2.4.0 kernel However this scm only goes back as far as 2.6.12 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Tom Rix --- v2: split from combined scsi,pcd patch drivers/block/paride/pcd.c | 87 +++++++++++++++++--------------------- 1 file changed, 38 insertions(+), 49 deletions(-) diff --git a/drivers/block/paride/pcd.c b/drivers/block/paride/pcd.c index f462ad67931a..2315918e3647 100644 --- a/drivers/block/paride/pcd.c +++ b/drivers/block/paride/pcd.c @@ -810,67 +810,56 @@ static void do_pcd_read_drq(void) =20 /* the audio_ioctl stuff is adapted from sr_ioctl.c */ =20 -static int pcd_audio_ioctl(struct cdrom_device_info *cdi, unsigned int cmd= , void *arg) +static int pcd_audio_ioctl(struct cdrom_device_info *cdi, unsigned int req= uest, void *arg) { struct pcd_unit *cd =3D cdi->handle; + char cmd[12] =3D { GPCMD_READ_TOC_PMA_ATIP, 0, 0, 0, 0, 0, 0, 0, 12, 0, 0= , 0 }; + char buffer[32] =3D {}; =20 - switch (cmd) { - + switch (request) { case CDROMREADTOCHDR: + { + struct cdrom_tochdr *tochdr =3D + (struct cdrom_tochdr *) arg; =20 - { - char cmd[12] =3D - { GPCMD_READ_TOC_PMA_ATIP, 0, 0, 0, 0, 0, 0, 0, 12, - 0, 0, 0 }; - struct cdrom_tochdr *tochdr =3D - (struct cdrom_tochdr *) arg; - char buffer[32]; - int r; - - r =3D pcd_atapi(cd, cmd, 12, buffer, "read toc header"); + if (pcd_atapi(cd, cmd, 12, buffer, "read toc header")) + return -EIO; =20 - tochdr->cdth_trk0 =3D buffer[2]; - tochdr->cdth_trk1 =3D buffer[3]; + tochdr->cdth_trk0 =3D buffer[2]; + tochdr->cdth_trk1 =3D buffer[3]; =20 - return r ? -EIO : 0; - } + return 0; + } =20 case CDROMREADTOCENTRY: - - { - char cmd[12] =3D - { GPCMD_READ_TOC_PMA_ATIP, 0, 0, 0, 0, 0, 0, 0, 12, - 0, 0, 0 }; - - struct cdrom_tocentry *tocentry =3D - (struct cdrom_tocentry *) arg; - unsigned char buffer[32]; - int r; - - cmd[1] =3D - (tocentry->cdte_format =3D=3D CDROM_MSF ? 0x02 : 0); - cmd[6] =3D tocentry->cdte_track; - - r =3D pcd_atapi(cd, cmd, 12, buffer, "read toc entry"); - - tocentry->cdte_ctrl =3D buffer[5] & 0xf; - tocentry->cdte_adr =3D buffer[5] >> 4; - tocentry->cdte_datamode =3D - (tocentry->cdte_ctrl & 0x04) ? 1 : 0; - if (tocentry->cdte_format =3D=3D CDROM_MSF) { - tocentry->cdte_addr.msf.minute =3D buffer[9]; - tocentry->cdte_addr.msf.second =3D buffer[10]; - tocentry->cdte_addr.msf.frame =3D buffer[11]; - } else - tocentry->cdte_addr.lba =3D - (((((buffer[8] << 8) + buffer[9]) << 8) - + buffer[10]) << 8) + buffer[11]; - - return r ? -EIO : 0; + { + struct cdrom_tocentry *tocentry =3D + (struct cdrom_tocentry *) arg; + + cmd[1] =3D (tocentry->cdte_format =3D=3D CDROM_MSF ? 0x02 : 0); + cmd[6] =3D tocentry->cdte_track; + + if (pcd_atapi(cd, cmd, 12, buffer, "read toc entry")) + return -EIO; + + tocentry->cdte_ctrl =3D buffer[5] & 0xf; + tocentry->cdte_adr =3D buffer[5] >> 4; + tocentry->cdte_datamode =3D + (tocentry->cdte_ctrl & 0x04) ? 1 : 0; + if (tocentry->cdte_format =3D=3D CDROM_MSF) { + tocentry->cdte_addr.msf.minute =3D buffer[9]; + tocentry->cdte_addr.msf.second =3D buffer[10]; + tocentry->cdte_addr.msf.frame =3D buffer[11]; + } else { + tocentry->cdte_addr.lba =3D + (((((buffer[8] << 8) + buffer[9]) << 8) + + buffer[10]) << 8) + buffer[11]; } =20 - default: + return 0; + } =20 + default: return -ENOSYS; } } --=20 2.27.0