diff options
| author | Kees Cook <keescook@chromium.org> | 2023-10-03 16:21:02 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-10-06 10:48:46 +0100 |
| commit | eaede99c3aeb38613c40a150f676f772faf2b42b (patch) | |
| tree | a763b88a594c39bdb8e8e29dde74f59fed8c4182 /net/netlink | |
| parent | 178e9bf9b57d7671e94d39848a8ed090fe9ee431 (diff) | |
netlink: Annotate struct netlink_policy_dump_state with __counted_by
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
As found with Coccinelle[1], add __counted_by for struct netlink_policy_dump_state.
Additionally update the size of the usage array length before accessing
it. This requires remembering the old size for the memset() and later
assignments.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Cc: netdev@vger.kernel.org
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink')
| -rw-r--r-- | net/netlink/policy.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/net/netlink/policy.c b/net/netlink/policy.c index 87e3de0fde89..e2f111edf66c 100644 --- a/net/netlink/policy.c +++ b/net/netlink/policy.c @@ -21,7 +21,7 @@ struct netlink_policy_dump_state { struct { const struct nla_policy *policy; unsigned int maxtype; - } policies[]; + } policies[] __counted_by(n_alloc); }; static int add_policy(struct netlink_policy_dump_state **statep, @@ -29,7 +29,7 @@ static int add_policy(struct netlink_policy_dump_state **statep, unsigned int maxtype) { struct netlink_policy_dump_state *state = *statep; - unsigned int n_alloc, i; + unsigned int old_n_alloc, n_alloc, i; if (!policy || !maxtype) return 0; @@ -52,12 +52,13 @@ static int add_policy(struct netlink_policy_dump_state **statep, if (!state) return -ENOMEM; - memset(&state->policies[state->n_alloc], 0, - flex_array_size(state, policies, n_alloc - state->n_alloc)); - - state->policies[state->n_alloc].policy = policy; - state->policies[state->n_alloc].maxtype = maxtype; + old_n_alloc = state->n_alloc; state->n_alloc = n_alloc; + memset(&state->policies[old_n_alloc], 0, + flex_array_size(state, policies, n_alloc - old_n_alloc)); + + state->policies[old_n_alloc].policy = policy; + state->policies[old_n_alloc].maxtype = maxtype; *statep = state; return 0; |