diff options
author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2021-10-18 15:16:12 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-10-27 09:56:51 +0200 |
commit | b721500c979b71a9f02eb84ca384082722c62d4e (patch) | |
tree | 530ffd6dc5cdd803cc54fc7fe450dca531933308 /fs/kernel_read_file.c | |
parent | 895ceeff31b1f5e01ac8d5567d48215bbbcf9d97 (diff) |
vfs: check fd has read access in kernel_read_file_from_fd()
commit 032146cda85566abcd1c4884d9d23e4e30a07e9a upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/kernel_read_file.c')
-rw-r--r-- | fs/kernel_read_file.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c index 90d255fbdd9b..c84d87f558cb 100644 --- a/fs/kernel_read_file.c +++ b/fs/kernel_read_file.c @@ -178,7 +178,7 @@ int kernel_read_file_from_fd(int fd, loff_t offset, void **buf, struct fd f = fdget(fd); int ret = -EBADF; - if (!f.file) + if (!f.file || !(f.file->f_mode & FMODE_READ)) goto out; ret = kernel_read_file(f.file, offset, buf, buf_size, file_size, id); |