diff options
| author | Magnus Karlsson | 2020-04-14 09:35:15 +0200 |
|---|---|---|
| committer | Daniel Borkmann | 2020-04-15 13:07:18 +0200 |
| commit | 99e3a236dd43d06c65af0a2ef9cb44306aef6e02 (patch) | |
| tree | 14527dbe4aed7324672dfc119739886f523697d0 /net | |
| parent | 89f33dcadb349eb926a92633e2c5f61466afc596 (diff) | |
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 <minhquangbui99@gmail.com>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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
Diffstat (limited to 'net')
| -rw-r--r-- | net/xdp/xdp_umem.c | 5 |
1 files changed, 2 insertions, 3 deletions
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; |