]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
vfs: check fd has read access in kernel_read_file_from_fd()
authorMatthew Wilcox (Oracle) <willy@infradead.org>
Mon, 18 Oct 2021 22:16:12 +0000 (15:16 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 19 Oct 2021 06:22:03 +0000 (20:22 -1000)
commit032146cda85566abcd1c4884d9d23e4e30a07e9a
tree94db8693ba1de0ac9090a2eb235071ae7ef7a98c
parentb0e901280d9860a0a35055f220e8e457f300f40a
vfs: check fd has read access in kernel_read_file_from_fd()

If we open a file without read access and then pass the fd to a syscall
whose implementation calls kernel_read_file_from_fd(), we get a warning
from __kernel_read():

        if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ)))

This currently affects both finit_module() and kexec_file_load(), but it
could affect other syscalls in the future.

Link: https://lkml.kernel.org/r/20211007220110.600005-1-willy@infradead.org
Fixes: b844f0ecbc56 ("vfs: define kernel_copy_file_from_fd()")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: Hao Sun <sunhao.th@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/kernel_read_file.c