]> git.baikalelectronics.ru Git - kernel.git/commit
md: use kzalloc() when bitmap is disabled
authorBenjamin Randazzo <benjamin@randazzo.fr>
Sat, 25 Jul 2015 14:36:50 +0000 (16:36 +0200)
committerNeilBrown <neilb@suse.com>
Mon, 3 Aug 2015 04:56:02 +0000 (14:56 +1000)
commitf7dc6c7fc8cd1a2931f9a703caf61254b4e843a4
tree510bad0d0725ea8c6bebd28bec5ec350637805c8
parent302b60d9a5195735fcc97dbf4056aa03b3e184cf
md: use kzalloc() when bitmap is disabled

In drivers/md/md.c get_bitmap_file() uses kmalloc() for creating a
mdu_bitmap_file_t called "file".

5769         file = kmalloc(sizeof(*file), GFP_NOIO);
5770         if (!file)
5771                 return -ENOMEM;

This structure is copied to user space at the end of the function.

5786         if (err == 0 &&
5787             copy_to_user(arg, file, sizeof(*file)))
5788                 err = -EFAULT

But if bitmap is disabled only the first byte of "file" is initialized
with zero, so it's possible to read some bytes (up to 4095) of kernel
space memory from user space. This is an information leak.

5775         /* bitmap disabled, zero the first byte and copy out */
5776         if (!mddev->bitmap_info.file)
5777                 file->pathname[0] = '\0';

Signed-off-by: Benjamin Randazzo <benjamin@randazzo.fr>
Signed-off-by: NeilBrown <neilb@suse.com>
drivers/md/md.c