[PATCH v1 06/14] mm/mshare: Check for mounted filesystem

Khalid Aziz
2022-04-11T16:09:20Z

Check if msharefs is mounted before performing any msharefs
operations to avoid inadvertent NULL pointer dereferences.

Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
---
mm/mshare.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/mm/mshare.c b/mm/mshare.c
index 85ccb7f02f33..cd2f7ad24d9d 100644
--- a/mm/mshare.c
+++ b/mm/mshare.c
@@ -176,6 +176,13 @@ SYSCALL_DEFINE5(mshare, const char __user *, name, unsigned long, addr,
struct qstr namestr;
int err = PTR_ERR(fname);

+ /*
+ * Is msharefs mounted? TODO: If not mounted, return error
+ * or automount?
+ */
+ if (msharefs_sb == NULL)
+ return -ENOENT;
+
/*
* Address range being shared must be aligned to pgdir
* boundary and its size must be a multiple of pgdir size
@@ -260,6 +267,9 @@ SYSCALL_DEFINE1(mshare_unlink, const char *, name)
struct mshare_data *info;
struct qstr namestr;

+ if (msharefs_sb == NULL)
+ return -ENOENT;
+
if (IS_ERR(fname))
goto err_out;

--
2.32.0