6.12-stable review patch. If anyone has any objections, please let me know.
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From: Qianchang Zhao pioooooooooip@gmail.com
commit 5d510ac31626ed157d2182149559430350cf2104 upstream.
When size equals the current i_size (including 0), the code used to call check_lock_range(filp, i_size, size - 1, WRITE), which computes `size - 1` and can underflow for size==0. Skip the equal case.
Cc: stable@vger.kernel.org Reported-by: Qianchang Zhao pioooooooooip@gmail.com Reported-by: Zhitong Liu liuzhitong1993@gmail.com Signed-off-by: Qianchang Zhao pioooooooooip@gmail.com Acked-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/smb/server/vfs.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/fs/smb/server/vfs.c +++ b/fs/smb/server/vfs.c @@ -333,6 +333,9 @@ static int check_lock_range(struct file struct file_lock_context *ctx = locks_inode_context(file_inode(filp)); int error = 0;
+ if (start == end) + return 0; + if (!ctx || list_empty_careful(&ctx->flc_posix)) return 0;
@@ -839,7 +842,7 @@ int ksmbd_vfs_truncate(struct ksmbd_work if (size < inode->i_size) { err = check_lock_range(filp, size, inode->i_size - 1, WRITE); - } else { + } else if (size > inode->i_size) { err = check_lock_range(filp, inode->i_size, size - 1, WRITE); }