Make sure unaligned descriptors that straddle the end of the UMEM are
considered invalid. Currently, descriptor validation is broken for
zero-copy mode which only checks descriptors at page granularity.
Descriptors that cross the end of the UMEM but not a page boundary may
be therefore incorrectly considered valid. The check needs to happen
before the page boundary and contiguity checks in
xp_desc_crosses_non_contig_pg. Do this check in
xp_unaligned_validate_desc instead like xp_check_unaligned already does.
Fixes: 2b43470add8c ("xsk: Introduce AF_XDP buffer allocation API")
Signed-off-by: Kal Conley <[email protected]>
---
include/net/xsk_buff_pool.h | 9 ++-------
net/xdp/xsk_queue.h | 1 +
2 files changed, 3 insertions(+), 7 deletions(-)
diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index 3e952e569418..d318c769b445 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -180,13 +180,8 @@ static inline bool xp_desc_crosses_non_contig_pg(struct xsk_buff_pool *pool,
if (likely(!cross_pg))
return false;
- if (pool->dma_pages_cnt) {
- return !(pool->dma_pages[addr >> PAGE_SHIFT] &
- XSK_NEXT_PG_CONTIG_MASK);
- }
-
- /* skb path */
- return addr + len > pool->addrs_cnt;
+ return pool->dma_pages_cnt &&
+ !(pool->dma_pages[addr >> PAGE_SHIFT] & XSK_NEXT_PG_CONTIG_MASK);
}
static inline u64 xp_aligned_extract_addr(struct xsk_buff_pool *pool, u64 addr)
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index bfb2a7e50c26..66c6f57c9c44 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -162,6 +162,7 @@ static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool,
return false;
if (base_addr >= pool->addrs_cnt || addr >= pool->addrs_cnt ||
+ addr + desc->len > pool->addrs_cnt ||
xp_desc_crosses_non_contig_pg(pool, addr, desc->len))
return false;
--
2.39.2
On Mon, 3 Apr 2023 at 16:38, Kal Conley <[email protected]> wrote:
>
> Make sure unaligned descriptors that straddle the end of the UMEM are
> considered invalid. Currently, descriptor validation is broken for
> zero-copy mode which only checks descriptors at page granularity.
> Descriptors that cross the end of the UMEM but not a page boundary may
> be therefore incorrectly considered valid. The check needs to happen
> before the page boundary and contiguity checks in
> xp_desc_crosses_non_contig_pg. Do this check in
> xp_unaligned_validate_desc instead like xp_check_unaligned already does.
Thanks for catching this Kal.
Acked-by: Magnus Karlsson <[email protected]>
> Fixes: 2b43470add8c ("xsk: Introduce AF_XDP buffer allocation API")
> Signed-off-by: Kal Conley <[email protected]>
> ---
> include/net/xsk_buff_pool.h | 9 ++-------
> net/xdp/xsk_queue.h | 1 +
> 2 files changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
> index 3e952e569418..d318c769b445 100644
> --- a/include/net/xsk_buff_pool.h
> +++ b/include/net/xsk_buff_pool.h
> @@ -180,13 +180,8 @@ static inline bool xp_desc_crosses_non_contig_pg(struct xsk_buff_pool *pool,
> if (likely(!cross_pg))
> return false;
>
> - if (pool->dma_pages_cnt) {
> - return !(pool->dma_pages[addr >> PAGE_SHIFT] &
> - XSK_NEXT_PG_CONTIG_MASK);
> - }
> -
> - /* skb path */
> - return addr + len > pool->addrs_cnt;
> + return pool->dma_pages_cnt &&
> + !(pool->dma_pages[addr >> PAGE_SHIFT] & XSK_NEXT_PG_CONTIG_MASK);
> }
>
> static inline u64 xp_aligned_extract_addr(struct xsk_buff_pool *pool, u64 addr)
> diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
> index bfb2a7e50c26..66c6f57c9c44 100644
> --- a/net/xdp/xsk_queue.h
> +++ b/net/xdp/xsk_queue.h
> @@ -162,6 +162,7 @@ static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool,
> return false;
>
> if (base_addr >= pool->addrs_cnt || addr >= pool->addrs_cnt ||
> + addr + desc->len > pool->addrs_cnt ||
> xp_desc_crosses_non_contig_pg(pool, addr, desc->len))
> return false;
>
> --
> 2.39.2
>
On 4/3/23 11:25 PM, Magnus Karlsson wrote:
> On Mon, 3 Apr 2023 at 16:38, Kal Conley <[email protected]> wrote:
>>
>> Make sure unaligned descriptors that straddle the end of the UMEM are
>> considered invalid. Currently, descriptor validation is broken for
>> zero-copy mode which only checks descriptors at page granularity.
>> Descriptors that cross the end of the UMEM but not a page boundary may
>> be therefore incorrectly considered valid. The check needs to happen
>> before the page boundary and contiguity checks in
>> xp_desc_crosses_non_contig_pg. Do this check in
>> xp_unaligned_validate_desc instead like xp_check_unaligned already does.
>
> Thanks for catching this Kal.
>
> Acked-by: Magnus Karlsson <[email protected]>
Is this case covered by an existing test?
> Is this case covered by an existing test?
>
No. I submitted a test but I was asked to make minor changes to it. I
plan to submit the test once this gets picked up on bpf-next.
On 4/5/23 12:48 PM, Kal Cutter Conley wrote:
>> Is this case covered by an existing test?
>>
>
> No. I submitted a test but I was asked to make minor changes to it. I
> plan to submit the test once this gets picked up on bpf-next.
Since you already have a test case, it is better to submit them together such
that this case can be covered earlier than later.
Other xskxceiver fixes have already landed to bpf-next. imo, I think for this
particular case, bpf-next for both the fix and the test is fine.
> Since you already have a test case, it is better to submit them together such
> that this case can be covered earlier than later.
>
> Other xskxceiver fixes have already landed to bpf-next. imo, I think for this
> particular case, bpf-next for both the fix and the test is fine.
Done. See: https://lore.kernel.org/all/[email protected]/