| Message ID | 20230728065819.139694-2-oleksandr@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | scsi: qedf: sanitise uaccess | expand |
From: Oleksandr Natalenko > Sent: 28 July 2023 07:58 > > The qedf_dbg_stop_io_on_error_cmd_read() function invokes sprintf() > directly on a __user pointer, which may crash the kernel. > > Avoid doing that by using a small on-stack buffer for sprintf() > and then calling simple_read_from_buffer() which does a proper > copy_to_user() call. > > Fixes: 61d8658b4a ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.") ... > diff --git a/drivers/scsi/qedf/qedf_debugfs.c b/drivers/scsi/qedf/qedf_debugfs.c > index a3ed681c8ce3f..4d1b99569d490 100644 > --- a/drivers/scsi/qedf/qedf_debugfs.c > +++ b/drivers/scsi/qedf/qedf_debugfs.c > @@ -185,18 +185,17 @@ qedf_dbg_stop_io_on_error_cmd_read(struct file *filp, char __user *buffer, > size_t count, loff_t *ppos) > { > int cnt; > + char cbuf[7]; > struct qedf_dbg_ctx *qedf_dbg = > (struct qedf_dbg_ctx *)filp->private_data; > struct qedf_ctx *qedf = container_of(qedf_dbg, > struct qedf_ctx, dbg_ctx); > > QEDF_INFO(qedf_dbg, QEDF_LOG_DEBUGFS, "entered\n"); > - cnt = sprintf(buffer, "%s\n", > + cnt = sprintf(cbuf, "%s\n", > qedf->stop_io_on_error ? "true" : "false"); You've made cbuf[] exactly just big enough. If anyone breathes on this code it could overflow. You really should use scnprintf() for safety. > > - cnt = min_t(int, count, cnt - *ppos); > - *ppos += cnt; > - return cnt; > + return simple_read_from_buffer(buffer, count, ppos, cbuf, cnt); Or just: if (gedf->stop_on_error) return simple_read_from_buffer(buffer, count, ppos, "true\n", 5); return simple_read_from_buffer(buffer, count, ppos, "false\n", 6); David > } > > static ssize_t > -- > 2.41.0 - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
Hello. On pátek 28. července 2023 17:23:25 CEST David Laight wrote: > From: Oleksandr Natalenko > > Sent: 28 July 2023 07:58 > > > > The qedf_dbg_stop_io_on_error_cmd_read() function invokes sprintf() > > directly on a __user pointer, which may crash the kernel. > > > > Avoid doing that by using a small on-stack buffer for sprintf() > > and then calling simple_read_from_buffer() which does a proper > > copy_to_user() call. > > > > Fixes: 61d8658b4a ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.") > ... > > diff --git a/drivers/scsi/qedf/qedf_debugfs.c b/drivers/scsi/qedf/qedf_debugfs.c > > index a3ed681c8ce3f..4d1b99569d490 100644 > > --- a/drivers/scsi/qedf/qedf_debugfs.c > > +++ b/drivers/scsi/qedf/qedf_debugfs.c > > @@ -185,18 +185,17 @@ qedf_dbg_stop_io_on_error_cmd_read(struct file *filp, char __user *buffer, > > size_t count, loff_t *ppos) > > { > > int cnt; > > + char cbuf[7]; > > struct qedf_dbg_ctx *qedf_dbg = > > (struct qedf_dbg_ctx *)filp->private_data; > > struct qedf_ctx *qedf = container_of(qedf_dbg, > > struct qedf_ctx, dbg_ctx); > > > > QEDF_INFO(qedf_dbg, QEDF_LOG_DEBUGFS, "entered\n"); > > - cnt = sprintf(buffer, "%s\n", > > + cnt = sprintf(cbuf, "%s\n", > > qedf->stop_io_on_error ? "true" : "false"); > > You've made cbuf[] exactly just big enough. > If anyone breathes on this code it could overflow. > You really should use scnprintf() for safety. OK, I'll do scnprintf(cbuf, sizeof(cbuf), ...) in the next version of the submission. Thanks. > > > > - cnt = min_t(int, count, cnt - *ppos); > > - *ppos += cnt; > > - return cnt; > > + return simple_read_from_buffer(buffer, count, ppos, cbuf, cnt); > > Or just: > if (gedf->stop_on_error) > return simple_read_from_buffer(buffer, count, ppos, "true\n", 5); > return simple_read_from_buffer(buffer, count, ppos, "false\n", 6); > > David > > > > } > > > > static ssize_t > > -- > > 2.41.0 > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales) > >
diff --git a/drivers/scsi/qedf/qedf_debugfs.c b/drivers/scsi/qedf/qedf_debugfs.c index a3ed681c8ce3f..4d1b99569d490 100644 --- a/drivers/scsi/qedf/qedf_debugfs.c +++ b/drivers/scsi/qedf/qedf_debugfs.c @@ -185,18 +185,17 @@ qedf_dbg_stop_io_on_error_cmd_read(struct file *filp, char __user *buffer, size_t count, loff_t *ppos) { int cnt; + char cbuf[7]; struct qedf_dbg_ctx *qedf_dbg = (struct qedf_dbg_ctx *)filp->private_data; struct qedf_ctx *qedf = container_of(qedf_dbg, struct qedf_ctx, dbg_ctx); QEDF_INFO(qedf_dbg, QEDF_LOG_DEBUGFS, "entered\n"); - cnt = sprintf(buffer, "%s\n", + cnt = sprintf(cbuf, "%s\n", qedf->stop_io_on_error ? "true" : "false"); - cnt = min_t(int, count, cnt - *ppos); - *ppos += cnt; - return cnt; + return simple_read_from_buffer(buffer, count, ppos, cbuf, cnt); } static ssize_t
The qedf_dbg_stop_io_on_error_cmd_read() function invokes sprintf() directly on a __user pointer, which may crash the kernel. Avoid doing that by using a small on-stack buffer for sprintf() and then calling simple_read_from_buffer() which does a proper copy_to_user() call. Fixes: 61d8658b4a ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.") Link: https://lore.kernel.org/lkml/20230724120241.40495-1-oleksandr@redhat.com/ Link: https://lore.kernel.org/linux-scsi/20230726101236.11922-1-skashyap@marvell.com/ Cc: Saurav Kashyap <skashyap@marvell.com> Cc: Rob Evers <revers@redhat.com> Cc: Johannes Thumshirn <Johannes.Thumshirn@wdc.com> Cc: Jozef Bacik <jobacik@redhat.com> Cc: Laurence Oberman <loberman@redhat.com> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: GR-QLogic-Storage-Upstream@marvell.com Cc: linux-scsi@vger.kernel.org Tested-by: Laurence Oberman <loberman@redhat.com> Signed-off-by: Oleksandr Natalenko <oleksandr@redhat.com> --- drivers/scsi/qedf/qedf_debugfs.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)