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[RFC,3/8] sg_write(): __get_user() can fail...

Message ID 20191017193925.25539-3-viro@ZenIV.linux.org.uk (mailing list archive)
State Mainlined
Commit 062c9d4527ccbdbf49139607efd44c9c3f82a2fd
Headers show
Series [RFC,1/8] sg_ioctl(): fix copyout handling | expand

Commit Message

Al Viro Oct. 17, 2019, 7:39 p.m. UTC 
From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/scsi/sg.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 026628aa556d..4c62237cdf37 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -640,13 +640,15 @@  sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
 	if (count < (SZ_SG_HEADER + 6))
 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
 
+	buf += SZ_SG_HEADER;
+	if (__get_user(opcode, buf))
+		return -EFAULT;
+
 	if (!(srp = sg_add_request(sfp))) {
 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sdp,
 					      "sg_write: queue full\n"));
 		return -EDOM;
 	}
-	buf += SZ_SG_HEADER;
-	__get_user(opcode, buf);
 	mutex_lock(&sfp->f_mutex);
 	if (sfp->next_cmd_len > 0) {
 		cmd_size = sfp->next_cmd_len;