While taking a look at '[PATCH net] pktgen: Avoid out-of-range in get_imix_entries' ([1]) and '[PATCH net v2] pktgen: Avoid out-of-bounds access in get_imix_entries' ([2], [3]) and doing some tests and code review I detected that the /proc/net/pktgen/... parsing logic does not honour the user given buffer bounds (resulting in out-of-bounds access).
This can be observed e.g. by the following simple test (sometimes the old/'longer' previous value is re-read from the buffer):
$ echo add_device lo@0 > /proc/net/pktgen/kpktgend_0
$ echo "min_pkt_size 12345" > /proc/net/pktgen/lo@0 && grep min_pkt_size /proc/net/pktgen/lo@0 Params: count 1000 min_pkt_size: 12345 max_pkt_size: 0 Result: OK: min_pkt_size=12345
$ echo -n "min_pkt_size 123" > /proc/net/pktgen/lo@0 && grep min_pkt_size /proc/net/pktgen/lo@0 Params: count 1000 min_pkt_size: 12345 max_pkt_size: 0 Result: OK: min_pkt_size=12345
$ echo "min_pkt_size 123" > /proc/net/pktgen/lo@0 && grep min_pkt_size /proc/net/pktgen/lo@0 Params: count 1000 min_pkt_size: 123 max_pkt_size: 0 Result: OK: min_pkt_size=123
So fix the out-of-bounds access (and two minor findings) and add a simple proc_net_pktgen selftest...
Regards, Peter
[1] https://lore.kernel.org/netdev/20241006221221.3744995-1-artem.chernyshev@red... [2] https://lore.kernel.org/netdev/20250109083039.14004-1-pchelkin@ispras.ru/ [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
Peter Seiderer (5): net: pktgen: replace ENOTSUPP with EOPNOTSUPP net: pktgen: enable 'param=value' parsing net: pktgen: fix access outside of user given buffer in pktgen_thread_write() net: pktgen: fix access outside of user given buffer in pktgen_if_write() selftest: net: add proc_net_pktgen
net/core/pktgen.c | 210 ++++--- tools/testing/selftests/net/Makefile | 1 + tools/testing/selftests/net/proc_net_pktgen.c | 575 ++++++++++++++++++ 3 files changed, 712 insertions(+), 74 deletions(-) create mode 100644 tools/testing/selftests/net/proc_net_pktgen.c