From: Justin Tee justin.tee@broadcom.com
[ Upstream commit c6087b82a9146826564a55c5ca0164cac40348f5 ]
A static code analysis tool flagged the possibility of buffer overflow when using copy_from_user() for a debugfs entry.
Currently, it is possible that copy_from_user() copies more bytes than what would fit in the mybuf char array. Add a min() restriction check between sizeof(mybuf) - 1 and nbytes passed from the userspace buffer to protect against buffer overflow.
Link: https://lore.kernel.org/r/20230301231626.9621-2-justintee8345@gmail.com Signed-off-by: Justin Tee justin.tee@broadcom.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/lpfc/lpfc_debugfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/lpfc/lpfc_debugfs.c b/drivers/scsi/lpfc/lpfc_debugfs.c index 69551132f304c..291fccf02d453 100644 --- a/drivers/scsi/lpfc/lpfc_debugfs.c +++ b/drivers/scsi/lpfc/lpfc_debugfs.c @@ -2046,6 +2046,7 @@ lpfc_debugfs_lockstat_write(struct file *file, const char __user *buf, char mybuf[64]; char *pbuf; int i; + size_t bsize;
/* Protect copy from user */ if (!access_ok(buf, nbytes)) @@ -2053,7 +2054,9 @@ lpfc_debugfs_lockstat_write(struct file *file, const char __user *buf,
memset(mybuf, 0, sizeof(mybuf));
- if (copy_from_user(mybuf, buf, nbytes)) + bsize = min(nbytes, (sizeof(mybuf) - 1)); + + if (copy_from_user(mybuf, buf, bsize)) return -EFAULT; pbuf = &mybuf[0];
@@ -2074,7 +2077,7 @@ lpfc_debugfs_lockstat_write(struct file *file, const char __user *buf, qp->lock_conflict.wq_access = 0; } } - return nbytes; + return bsize; } #endif