From: "Matthew Wilcox (Oracle)" <willy@infradead.org> stable inclusion from stable-5.10.76 commit b721500c979b71a9f02eb84ca384082722c62d4e bugzilla: 182988 https://gitee.com/openeuler/kernel/issues/I4IAHF Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- 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> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- fs/kernel_read_file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c index 87aac4c72c37..1b07550485b9 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); -- 2.20.1