On Thu, Mar 14, 2019 at 09:26:53AM -0700, Zubin Mithra wrote:
From: Eric Biggers ebiggers@google.com
commit 4aa68e07d845562561f5e73c04aa521376e95252 upstream
When checking for permission to view keys whilst reading from /proc/keys, we should use the credentials with which the /proc/keys file was opened. This is because, in a classic type of exploit, it can be possible to bypass checks for the *current* credentials by passing the file descriptor to a suid program.
Following commit 34dbbcdbf633 ("Make file credentials available to the seqfile interfaces") we can finally fix it. So let's do it.
Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: Zubin Mithra zsm@chromium.org
- A test confirmed that when reading from a file descriptor
corresponding to /proc/keys the permissions for the reader were being used instead of the permissions of the user who opened the file.
This patch is required for 4.4.y as well; however, the original patch will apply cleanly there. I'll send a separate request for the same.
Now queued up, thanks.
greg k-h