It's getting more common to run nested container environments for
testing cloud software. One of such examples is Kind [1] which runs a
Kubernetes cluster in Docker containers on a single host. Each container
acts as a Kubernetes node, and thus can run any Pod (aka container)
inside the former. This approach simplifies testing a lot, as it
eliminates complicated VM setups.
Unfortunately, such a setup breaks some functionality when cgroupv2 BPF
programs are used for load-balancing. The load-balancer BPF program
needs to detect whether a request originates from the host netns or a
container netns in order to allow some access, e.g. to a service via a
loopback IP address. Typically, the programs detect this by comparing
netns cookies with the one of the init ns via a call to
bpf_get_netns_cookie(NULL). However, in nested environments the latter
cannot be used given the Kubernetes node's netns is outside the init ns.
To fix this, we need to pass the Kubernetes node netns cookie to the
program in a different way: by extending getsockopt() with a
SO_NETNS_COOKIE option, the orchestrator which runs in the Kubernetes
node netns can retrieve the cookie and pass it to the program instead.
Thus, this is following up on Eric's commit 3d368ab87cf6 ("net:
initialize net->net_cookie at netns setup") to allow retrieval via
SO_NETNS_COOKIE. This is also in line in how we retrieve socket cookie
via SO_COOKIE.
[1] https://kind.sigs.k8s.io/
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Cc: Eric Dumazet <edumazet@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ Upstream commit 147d8622f2a26ef34beacc60e1ed8b66c2fa457f ]
When userspace calls mprotect() to enable ADI on an address range,
do_mprotect_pkey() calls arch_validate_prot() to validate new
protection flags. arch_validate_prot() for sparc looks at the first
VMA associated with address range to verify if ADI can indeed be
enabled on this address range. This has two issues - (1) Address
range might cover multiple VMAs while arch_validate_prot() looks at
only the first VMA, (2) arch_validate_prot() peeks at VMA without
holding mmap lock which can result in race condition.
arch_validate_flags() from commit c462ac288f2c ("mm: Introduce
arch_validate_flags()") allows for VMA flags to be validated for all
VMAs that cover the address range given by user while holding mmap
lock. This patch updates sparc code to move the VMA check from
arch_validate_prot() to arch_validate_flags() to fix above two
issues.
Suggested-by: Jann Horn <jannh@google.com>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Martynas Pumputis