If maxBuf is small but non-zero, it could result in a zero sized lock
element array which we would then try and access OOB.
Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
---
fs/cifs/file.c | 8 ++++----
fs/cifs/smb2file.c | 4 ++--
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 673f948e4760..5b6f8392d9db 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1132,10 +1132,10 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
- * and check it for zero before using.
+ * and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
- if (!max_buf) {
+ if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE))) {
free_xid(xid);
return -EINVAL;
}
@@ -1476,10 +1476,10 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
- * and check it for zero before using.
+ * and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
- if (!max_buf)
+ if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE)))
return -EINVAL;
BUILD_BUG_ON(sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE) >
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index eff01ed6db0a..b204e84b87fb 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -122,10 +122,10 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
/*
* Accessing maxBuf is racy with cifs_reconnect - need to store value
- * and check it for zero before using.
+ * and check it before using.
*/
max_buf = tcon->ses->server->maxBuf;
- if (!max_buf)
+ if (max_buf < sizeof(struct smb2_lock_element))
return -EINVAL;
BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
--
2.17.2
