scsi: lpfc: Prevent buffer overflow crashes in debugfs with malformed user input

[ Upstream commit f8191d40aa612981ce897e66cda6a88db8df17bb ]

Malformed user input to debugfs results in buffer overflow crashes.  Adapt
input string lengths to fit within internal buffers, leaving space for NULL
terminators.

Link: https://lore.kernel.org/r/20220701211425.2708-3-jsmart2021@gmail.com
Co-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/scsi/lpfc/lpfc_debugfs.c b/drivers/scsi/lpfc/lpfc_debugfs.c
index 08b2e85..79bc86b 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_debugfs.c
+++ b/drivers/scsi/lpfc/lpfc_debugfs.c
@@ -2607,8 +2607,8 @@ lpfc_debugfs_multixripools_write(struct file *file, const char __user *buf,
        struct lpfc_sli4_hdw_queue *qp;
        struct lpfc_multixri_pool *multixri_pool;
 
-       if (nbytes > 64)
-               nbytes = 64;
+       if (nbytes > sizeof(mybuf) - 1)
+               nbytes = sizeof(mybuf) - 1;
 
        memset(mybuf, 0, sizeof(mybuf));
 
@@ -2688,8 +2688,8 @@ lpfc_debugfs_nvmestat_write(struct file *file, const char __user *buf,
        if (!phba->targetport)
                return -ENXIO;
 
-       if (nbytes > 64)
-               nbytes = 64;
+       if (nbytes > sizeof(mybuf) - 1)
+               nbytes = sizeof(mybuf) - 1;
 
        memset(mybuf, 0, sizeof(mybuf));
 
@@ -2826,8 +2826,8 @@ lpfc_debugfs_ioktime_write(struct file *file, const char __user *buf,
        char mybuf[64];
        char *pbuf;
 
-       if (nbytes > 64)
-               nbytes = 64;
+       if (nbytes > sizeof(mybuf) - 1)
+               nbytes = sizeof(mybuf) - 1;
 
        memset(mybuf, 0, sizeof(mybuf));
 
@@ -2954,8 +2954,8 @@ lpfc_debugfs_nvmeio_trc_write(struct file *file, const char __user *buf,
        char mybuf[64];
        char *pbuf;
 
-       if (nbytes > 63)
-               nbytes = 63;
+       if (nbytes > sizeof(mybuf) - 1)
+               nbytes = sizeof(mybuf) - 1;
 
        memset(mybuf, 0, sizeof(mybuf));
 
@@ -3060,8 +3060,8 @@ lpfc_debugfs_hdwqstat_write(struct file *file, const char __user *buf,
        char *pbuf;
        int i;
 
-       if (nbytes > 64)
-               nbytes = 64;
+       if (nbytes > sizeof(mybuf) - 1)
+               nbytes = sizeof(mybuf) - 1;
 
        memset(mybuf, 0, sizeof(mybuf));