Check we're going to free a reasonable number of frags in token_count before starting the loop, to prevent looping too long.
Also minor code cleanups: - Flip checks to reduce indentation. - Use sizeof(*tokens) everywhere for consistentcy.
Cc: Yi Lai yi1.lai@linux.intel.com
Signed-off-by: Mina Almasry almasrymina@google.com
--- net/core/sock.c | 46 ++++++++++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 18 deletions(-)
diff --git a/net/core/sock.c b/net/core/sock.c index 7f398bd07fb7..8603b8d87f2e 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1047,11 +1047,12 @@ static int sock_reserve_memory(struct sock *sk, int bytes)
#ifdef CONFIG_PAGE_POOL
-/* This is the number of tokens that the user can SO_DEVMEM_DONTNEED in +/* This is the number of frags that the user can SO_DEVMEM_DONTNEED in * 1 syscall. The limit exists to limit the amount of memory the kernel - * allocates to copy these tokens. + * allocates to copy these tokens, and to prevent looping over the frags for + * too long. */ -#define MAX_DONTNEED_TOKENS 128 +#define MAX_DONTNEED_FRAGS 1024
static noinline_for_stack int sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optlen) @@ -1059,43 +1060,52 @@ sock_devmem_dontneed(struct sock *sk, sockptr_t optval, unsigned int optlen) unsigned int num_tokens, i, j, k, netmem_num = 0; struct dmabuf_token *tokens; netmem_ref netmems[16]; + u64 num_frags = 0; int ret = 0;
if (!sk_is_tcp(sk)) return -EBADF;
- if (optlen % sizeof(struct dmabuf_token) || - optlen > sizeof(*tokens) * MAX_DONTNEED_TOKENS) + if (optlen % sizeof(*tokens) || + optlen > sizeof(*tokens) * MAX_DONTNEED_FRAGS) return -EINVAL;
- tokens = kvmalloc_array(optlen, sizeof(*tokens), GFP_KERNEL); + num_tokens = optlen / sizeof(*tokens); + tokens = kvmalloc_array(num_tokens, sizeof(*tokens), GFP_KERNEL); if (!tokens) return -ENOMEM;
- num_tokens = optlen / sizeof(struct dmabuf_token); if (copy_from_sockptr(tokens, optval, optlen)) { kvfree(tokens); return -EFAULT; }
+ for (i = 0; i < num_tokens; i++) { + num_frags += tokens[i].token_count; + if (num_frags > MAX_DONTNEED_FRAGS) { + kvfree(tokens); + return -E2BIG; + } + } + xa_lock_bh(&sk->sk_user_frags); for (i = 0; i < num_tokens; i++) { for (j = 0; j < tokens[i].token_count; j++) { netmem_ref netmem = (__force netmem_ref)__xa_erase( &sk->sk_user_frags, tokens[i].token_start + j);
- if (netmem && - !WARN_ON_ONCE(!netmem_is_net_iov(netmem))) { - netmems[netmem_num++] = netmem; - if (netmem_num == ARRAY_SIZE(netmems)) { - xa_unlock_bh(&sk->sk_user_frags); - for (k = 0; k < netmem_num; k++) - WARN_ON_ONCE(!napi_pp_put_page(netmems[k])); - netmem_num = 0; - xa_lock_bh(&sk->sk_user_frags); - } - ret++; + if (!netmem || WARN_ON_ONCE(!netmem_is_net_iov(netmem))) + continue; + + netmems[netmem_num++] = netmem; + if (netmem_num == ARRAY_SIZE(netmems)) { + xa_unlock_bh(&sk->sk_user_frags); + for (k = 0; k < netmem_num; k++) + WARN_ON_ONCE(!napi_pp_put_page(netmems[k])); + netmem_num = 0; + xa_lock_bh(&sk->sk_user_frags); } + ret++; } }
-- 2.47.0.163.g1226f6d8fa-goog