bpf: fix refcnt overflow

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[ Upstream commit 92117d8443 ]

On a system with >32Gbyte of phyiscal memory and infinite RLIMIT_MEMLOCK,
the malicious application may overflow 32-bit bpf program refcnt.
It's also possible to overflow map refcnt on 1Tb system.
Impose 32k hard limit which means that the same bpf program or
map cannot be shared by more than 32k processes.

Fixes: 1be7f75d16 ("bpf: enable non-root eBPF programs")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Alexei Starovoitov 2016-04-27 18:56:20 -07:00 • committed by Greg Kroah-Hartman

parent 608d2c3c7a

commit 3899251bdb

4 changed files with 33 additions and 12 deletions

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3

include/linux/bpf.h

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7

kernel/bpf/inode.c

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24

kernel/bpf/syscall.c

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11

kernel/bpf/verifier.c

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