[PATCH v2 0/3] scsi: qedf: sanitise uaccess

[PATCH v2 0/3] scsi: qedf: sanitise uaccess

[Oleksandr Natalenko]

qedf driver, debugfs part of it specifically, touches __user pointers
directly for printing out info to userspace via sprintf(), which may
cause crash like this:

BUG: unable to handle kernel paging request at 00007ffd1d6b43a0
IP: [<ffffffffaa7a882a>] string.isra.7+0x6a/0xf0
Oops: 0003 [#1] SMP
Call Trace:
 [<ffffffffaa7a9f31>] vsnprintf+0x201/0x6a0
 [<ffffffffaa7aa556>] sprintf+0x56/0x80
 [<ffffffffc04227ed>] qedf_dbg_stop_io_on_error_cmd_read+0x6d/0x90 [qedf]
 [<ffffffffaa65bb2f>] vfs_read+0x9f/0x170
 [<ffffffffaa65cb82>] SyS_pread64+0x92/0xc0

Avoid this by preparing the info in a kernel buffer first, either
allocated on stack for small printouts, or via vmalloc() for big ones,
and then copying it to the userspace properly.

Changes since v1 [1]:

  * use scnprintf() for on-stack buffers too
  * adjust an on-stack buffer size in qedf_dbg_debug_cmd_read() to be a
    multiple of 8, and also size it properly
  * accumulate acks and reviews

[1] https://lore.kernel.org/lkml/20230728065819.139694-1-oleksandr@redhat.com/

Oleksandr Natalenko (3):
  scsi: qedf: do not touch __user pointer in
    qedf_dbg_stop_io_on_error_cmd_read() directly
  scsi: qedf: do not touch __user pointer in qedf_dbg_debug_cmd_read()
    directly
  scsi: qedf: do not touch __user pointer in qedf_dbg_fp_int_cmd_read()
    directly

 drivers/scsi/qedf/qedf_dbg.h     |  2 ++
 drivers/scsi/qedf/qedf_debugfs.c | 35 +++++++++++++++++++-------------
 2 files changed, 23 insertions(+), 14 deletions(-)

-- 
2.41.0

[PATCH v2 1/3] scsi: qedf: do not touch __user pointer in qedf_dbg_stop_io_on_error_cmd_read() directly

[Oleksandr Natalenko]

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 scnprintf()
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: David Laight <David.Laight@ACULAB.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
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Acked-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Oleksandr Natalenko <oleksandr@redhat.com>
---
 drivers/scsi/qedf/qedf_debugfs.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/qedf/qedf_debugfs.c b/drivers/scsi/qedf/qedf_debugfs.c
index a3ed681c8ce3f..3eb4334ac6a32 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 = scnprintf(cbuf, sizeof(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
-- 
2.41.0

[PATCH v2 2/3] scsi: qedf: do not touch __user pointer in qedf_dbg_debug_cmd_read() directly

[Oleksandr Natalenko]

The qedf_dbg_debug_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 scnprintf()
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: David Laight <David.Laight@ACULAB.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
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Acked-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Oleksandr Natalenko <oleksandr@redhat.com>
---
 drivers/scsi/qedf/qedf_debugfs.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/qedf/qedf_debugfs.c b/drivers/scsi/qedf/qedf_debugfs.c
index 3eb4334ac6a32..1c5716540e465 100644
--- a/drivers/scsi/qedf/qedf_debugfs.c
+++ b/drivers/scsi/qedf/qedf_debugfs.c
@@ -138,15 +138,14 @@ qedf_dbg_debug_cmd_read(struct file *filp, char __user *buffer, size_t count,
 			loff_t *ppos)
 {
 	int cnt;
+	char cbuf[32];
 	struct qedf_dbg_ctx *qedf_dbg =
 				(struct qedf_dbg_ctx *)filp->private_data;
 
 	QEDF_INFO(qedf_dbg, QEDF_LOG_DEBUGFS, "debug mask=0x%x\n", qedf_debug);
-	cnt = sprintf(buffer, "debug mask = 0x%x\n", qedf_debug);
+	cnt = scnprintf(cbuf, sizeof(cbuf), "debug mask = 0x%x\n", qedf_debug);
 
-	cnt = min_t(int, count, cnt - *ppos);
-	*ppos += cnt;
-	return cnt;
+	return simple_read_from_buffer(buffer, count, ppos, cbuf, cnt);
 }
 
 static ssize_t
-- 
2.41.0

[PATCH v2 3/3] scsi: qedf: do not touch __user pointer in qedf_dbg_fp_int_cmd_read() directly

[Oleksandr Natalenko]

The qedf_dbg_fp_int_cmd_read() function invokes sprintf()
directly on a __user pointer, which may crash the kernel.

Avoid doing that by vmalloc()'ating a buffer for scnprintf()
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: David Laight <David.Laight@ACULAB.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
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Acked-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Oleksandr Natalenko <oleksandr@redhat.com>
---
 drivers/scsi/qedf/qedf_dbg.h     |  2 ++
 drivers/scsi/qedf/qedf_debugfs.c | 21 +++++++++++++++------
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/qedf/qedf_dbg.h b/drivers/scsi/qedf/qedf_dbg.h
index f4d81127239eb..5ec2b817c694a 100644
--- a/drivers/scsi/qedf/qedf_dbg.h
+++ b/drivers/scsi/qedf/qedf_dbg.h
@@ -59,6 +59,8 @@ extern uint qedf_debug;
 #define QEDF_LOG_NOTICE	0x40000000	/* Notice logs */
 #define QEDF_LOG_WARN		0x80000000	/* Warning logs */
 
+#define QEDF_DEBUGFS_LOG_LEN (2 * PAGE_SIZE)
+
 /* Debug context structure */
 struct qedf_dbg_ctx {
 	unsigned int host_no;
diff --git a/drivers/scsi/qedf/qedf_debugfs.c b/drivers/scsi/qedf/qedf_debugfs.c
index 1c5716540e465..451fd236bfd05 100644
--- a/drivers/scsi/qedf/qedf_debugfs.c
+++ b/drivers/scsi/qedf/qedf_debugfs.c
@@ -8,6 +8,7 @@
 #include <linux/uaccess.h>
 #include <linux/debugfs.h>
 #include <linux/module.h>
+#include <linux/vmalloc.h>
 
 #include "qedf.h"
 #include "qedf_dbg.h"
@@ -98,7 +99,9 @@ static ssize_t
 qedf_dbg_fp_int_cmd_read(struct file *filp, char __user *buffer, size_t count,
 			 loff_t *ppos)
 {
+	ssize_t ret;
 	size_t cnt = 0;
+	char *cbuf;
 	int id;
 	struct qedf_fastpath *fp = NULL;
 	struct qedf_dbg_ctx *qedf_dbg =
@@ -108,19 +111,25 @@ qedf_dbg_fp_int_cmd_read(struct file *filp, char __user *buffer, size_t count,
 
 	QEDF_INFO(qedf_dbg, QEDF_LOG_DEBUGFS, "entered\n");
 
-	cnt = sprintf(buffer, "\nFastpath I/O completions\n\n");
+	cbuf = vmalloc(QEDF_DEBUGFS_LOG_LEN);
+	if (!cbuf)
+		return 0;
+
+	cnt += scnprintf(cbuf + cnt, QEDF_DEBUGFS_LOG_LEN - cnt, "\nFastpath I/O completions\n\n");
 
 	for (id = 0; id < qedf->num_queues; id++) {
 		fp = &(qedf->fp_array[id]);
 		if (fp->sb_id == QEDF_SB_ID_NULL)
 			continue;
-		cnt += sprintf((buffer + cnt), "#%d: %lu\n", id,
-			       fp->completions);
+		cnt += scnprintf(cbuf + cnt, QEDF_DEBUGFS_LOG_LEN - cnt,
+				 "#%d: %lu\n", id, fp->completions);
 	}
 
-	cnt = min_t(int, count, cnt - *ppos);
-	*ppos += cnt;
-	return cnt;
+	ret = simple_read_from_buffer(buffer, count, ppos, cbuf, cnt);
+
+	vfree(cbuf);
+
+	return ret;
 }
 
 static ssize_t
-- 
2.41.0

Re: [PATCH v2 0/3] scsi: qedf: sanitise uaccess

[Laurence Oberman]

On Mon, 2023-07-31 at 10:40 +0200, Oleksandr Natalenko wrote:
> qedf driver, debugfs part of it specifically, touches __user pointers
> directly for printing out info to userspace via sprintf(), which may
> cause crash like this:
> 
> BUG: unable to handle kernel paging request at 00007ffd1d6b43a0
> IP: [<ffffffffaa7a882a>] string.isra.7+0x6a/0xf0
> Oops: 0003 [#1] SMP
> Call Trace:
>  [<ffffffffaa7a9f31>] vsnprintf+0x201/0x6a0
>  [<ffffffffaa7aa556>] sprintf+0x56/0x80
>  [<ffffffffc04227ed>] qedf_dbg_stop_io_on_error_cmd_read+0x6d/0x90
> [qedf]
>  [<ffffffffaa65bb2f>] vfs_read+0x9f/0x170
>  [<ffffffffaa65cb82>] SyS_pread64+0x92/0xc0
> 
> Avoid this by preparing the info in a kernel buffer first, either
> allocated on stack for small printouts, or via vmalloc() for big
> ones,
> and then copying it to the userspace properly.
> 
> Changes since v1 [1]:
> 
>   * use scnprintf() for on-stack buffers too
>   * adjust an on-stack buffer size in qedf_dbg_debug_cmd_read() to be
> a
>     multiple of 8, and also size it properly
>   * accumulate acks and reviews
> 
> [1]
> https://lore.kernel.org/lkml/20230728065819.139694-1-oleksandr@redhat.com/
> 
> Oleksandr Natalenko (3):
>   scsi: qedf: do not touch __user pointer in
>     qedf_dbg_stop_io_on_error_cmd_read() directly
>   scsi: qedf: do not touch __user pointer in
> qedf_dbg_debug_cmd_read()
>     directly
>   scsi: qedf: do not touch __user pointer in
> qedf_dbg_fp_int_cmd_read()
>     directly
> 
>  drivers/scsi/qedf/qedf_dbg.h     |  2 ++
>  drivers/scsi/qedf/qedf_debugfs.c | 35 +++++++++++++++++++-----------
> --
>  2 files changed, 23 insertions(+), 14 deletions(-)
> 
In case it's needed

For the series v2 against 6.5-rc3
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Tested-by: Laurence Oberman <loberman@redhat.com>

Test notes

Linux segstorage5 6.5.0-rc3+

[root@segstorage5 qedf]# cd host2
[root@segstorage5 host2]# ls
clear_stats  debug  driver_stats  fp_int  io_trace  offload_stats 
stop_io_on_error

[root@segstorage5 host2]# cat stop_io_on_error
false

[root@segstorage5 host2]# cat fp_int

Fastpath I/O completions

#0: 844
#1: 990
#2: 1036
#3: 1116
#4: 953
#5: 822
#6: 882
#7: 1073
#8: 1030
#9: 992
#10: 789
#11: 705
#12: 490
#13: 532
#14: 646
#15: 705

[root@segstorage5 host2]# cat debug
debug mask = 0x2

Re: [PATCH v2 0/3] scsi: qedf: sanitise uaccess

[Martin K. Petersen]

Oleksandr,

> qedf driver, debugfs part of it specifically, touches __user pointers
> directly for printing out info to userspace via sprintf(), which may
> cause crash like this:

Applied to 6.6/scsi-staging, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH v2 0/3] scsi: qedf: sanitise uaccess

[Oleksandr Natalenko]

[-- Attachment #1: Type: text/plain, Size: 415 bytes --]

On pondělí 31. července 2023 20:43:34 CEST Martin K. Petersen wrote:
> 
> Oleksandr,
> 
> > qedf driver, debugfs part of it specifically, touches __user pointers
> > directly for printing out info to userspace via sprintf(), which may
> > cause crash like this:
> 
> Applied to 6.6/scsi-staging, thanks!

Thank you all.

-- 
Oleksandr Natalenko (post-factum)
Principal Software Maintenance Engineer

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: [PATCH v2 0/3] scsi: qedf: sanitise uaccess

[Martin K. Petersen]

On Mon, 31 Jul 2023 10:40:31 +0200, Oleksandr Natalenko wrote:

> qedf driver, debugfs part of it specifically, touches __user pointers
> directly for printing out info to userspace via sprintf(), which may
> cause crash like this:
> 
> BUG: unable to handle kernel paging request at 00007ffd1d6b43a0
> IP: [<ffffffffaa7a882a>] string.isra.7+0x6a/0xf0
> Oops: 0003 [#1] SMP
> Call Trace:
>  [<ffffffffaa7a9f31>] vsnprintf+0x201/0x6a0
>  [<ffffffffaa7aa556>] sprintf+0x56/0x80
>  [<ffffffffc04227ed>] qedf_dbg_stop_io_on_error_cmd_read+0x6d/0x90 [qedf]
>  [<ffffffffaa65bb2f>] vfs_read+0x9f/0x170
>  [<ffffffffaa65cb82>] SyS_pread64+0x92/0xc0
> 
> [...]

Applied to 6.6/scsi-queue, thanks!

[1/3] scsi: qedf: do not touch __user pointer in qedf_dbg_stop_io_on_error_cmd_read() directly
      https://git.kernel.org/mkp/scsi/c/7d3d20dee4f6
[2/3] scsi: qedf: do not touch __user pointer in qedf_dbg_debug_cmd_read() directly
      https://git.kernel.org/mkp/scsi/c/31b5991a9a91
[3/3] scsi: qedf: do not touch __user pointer in qedf_dbg_fp_int_cmd_read() directly
      https://git.kernel.org/mkp/scsi/c/25dbc20deab5

-- 
Martin K. Petersen	Oracle Linux Engineering