From dfa74909cb6b846cbdabfc2c3c7de1d507fca075 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Sun, 12 Apr 2020 07:32:04 -0600 Subject: xdp: Reset prog in dev_change_xdp_fd when fd is negative MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The commit mentioned in the Fixes tag reuses the local prog variable when looking up an expected_fd. The variable is not reset when fd < 0 causing a detach with the expected_fd set to actually call dev_xdp_install for the existing program. The end result is that the detach does not happen. Fixes: 92234c8f15c8 ("xdp: Support specifying expected existing program when attaching XDP") Signed-off-by: David Ahern Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Kicinski Reviewed-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/20200412133204.43847-1-dsahern@kernel.org --- net/core/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/core/dev.c b/net/core/dev.c index df8097b8e286..522288177bbd 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8667,8 +8667,8 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, const struct net_device_ops *ops = dev->netdev_ops; enum bpf_netdev_command query; u32 prog_id, expected_id = 0; - struct bpf_prog *prog = NULL; bpf_op_t bpf_op, bpf_chk; + struct bpf_prog *prog; bool offload; int err; @@ -8734,6 +8734,7 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, } else { if (!prog_id) return 0; + prog = NULL; } err = dev_xdp_install(dev, bpf_op, extack, flags, prog); -- cgit v1.2.3 From 99e3a236dd43d06c65af0a2ef9cb44306aef6e02 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Tue, 14 Apr 2020 09:35:15 +0200 Subject: xsk: Add missing check on user supplied headroom size Add a check that the headroom cannot be larger than the available space in the chunk. In the current code, a malicious user can set the headroom to a value larger than the chunk size minus the fixed XDP headroom. That way packets with a length larger than the supported size in the umem could get accepted and result in an out-of-bounds write. Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt") Reported-by: Bui Quang Minh Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Link: https://bugzilla.kernel.org/show_bug.cgi?id=207225 Link: https://lore.kernel.org/bpf/1586849715-23490-1-git-send-email-magnus.karlsson@intel.com --- net/xdp/xdp_umem.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'net') diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index fa7bb5e060d0..ed7a6060f73c 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -343,7 +343,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) u32 chunk_size = mr->chunk_size, headroom = mr->headroom; unsigned int chunks, chunks_per_page; u64 addr = mr->addr, size = mr->len; - int size_chk, err; + int err; if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) { /* Strictly speaking we could support this, if: @@ -382,8 +382,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) return -EINVAL; } - size_chk = chunk_size - headroom - XDP_PACKET_HEADROOM; - if (size_chk < 0) + if (headroom >= chunk_size - XDP_PACKET_HEADROOM) return -EINVAL; umem->address = (unsigned long)addr; -- cgit v1.2.3