[v8,37/38] sg: warn v3 write system call users

Commit Message

Douglas Gilbert March 2, 2020, 3:32 a.m. UTC

Should generate one log message per kernel run when the write()
system call is used with the sg interface version 3. Due to
security concerns suggest that they use ioctl(SG_SUBMIT_v3)
instead.

Sg interface version 1 or 2 based code may also be calling
write() in this context. There is no easy solution for them
(short of upgrading their interface to version 3 or 4), so
don't produce a warning suggesting the conversion will be
simple.

Reviewed-by: Hannes Reinecke <[e-mail]>
Signed-off-by: Douglas Gilbert <[e-mail]>
---
 drivers/scsi/sg.c | 4 ++++
 1 file changed, 4 insertions(+)

Patch

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 0d835ae88c35..d899c2f18acf 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -645,6 +645,10 @@  sg_write(struct file *filp, const char __user *p, size_t count, loff_t *ppos)
 				     __func__);
 			return -EPERM;
 		}
+		WARN_ONCE(true, "Please use %s instead of write(),\n%s\n",
+			  "ioctl(SG_SUBMIT_V3)",
+			  "  See: http://sg.danny.cz/sg/sg_v40.html");
+
 		res = sg_v3_submit(filp, sfp, h3p, false, NULL);
 		return res < 0 ? res : (int)count;
 	}