On 10/10/22 15:00, Paul Moore wrote:
On Mon, Oct 10, 2022 at 5:58 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote:Commit 4ff09db1b79b ("bpf: net: Change sk_getsockopt() to take the sockptr_t argument") made it possible to call sk_getsockopt() with both user and kernel address space buffers through the use of the sockptr_t type. Unfortunately at the time of conversion the security_socket_getpeersec_stream() LSM hook was written to only accept userspace buffers, and in a desire to avoid having to change the LSM hook the commit author simply passed the sockptr_t's userspace buffer pointer. Since the only sk_getsockopt() callers at the time of conversion which used kernel sockptr_t buffers did not allow SO_PEERSEC, and hence the security_socket_getpeersec_stream() hook, this was acceptable but also very fragile as future changes presented the possibility of silently passing kernel space pointers to the LSM hook. There are several ways to protect against this, including careful code review of future commits, but since relying on code review to catch bugs is a recipe for disaster and the upstream eBPF maintainer is "strongly against defensive programming", this patch updates the LSM hook, and all of the implementations to support sockptr_t and safely handle both user and kernel space buffers. Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx> --- include/linux/lsm_hook_defs.h | 2 +- include/linux/lsm_hooks.h | 4 ++-- include/linux/security.h | 11 +++++++---- net/core/sock.c | 3 ++- security/apparmor/lsm.c | 29 +++++++++++++---------------- security/security.c | 6 +++--- security/selinux/hooks.c | 13 ++++++------- security/smack/smack_lsm.c | 19 ++++++++++--------- 8 files changed, 44 insertions(+), 43 deletions(-)Casey and John, could you please look over the Smack and AppArmor bits of this patch when you get a chance? I did my best on the conversion, but I would appreciate a review by the experts :)
yes, I plan to look at it this weekend
