Patch "xsk: Add missing overflow check in xdp_umem_reg" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    xsk: Add missing overflow check in xdp_umem_reg

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xsk-add-missing-overflow-check-in-xdp_umem_reg.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 9936a8ef698f0412dbcbdeb400164cc9ca061637
Author: Kal Conley <kal.conley@xxxxxxxxxxx>
Date:   Wed Mar 8 18:40:13 2023 +0100

    xsk: Add missing overflow check in xdp_umem_reg
    
    [ Upstream commit c7df4813b149362248d6ef7be41a311e27bf75fe ]
    
    The number of chunks can overflow u32. Make sure to return -EINVAL on
    overflow. Also remove a redundant u32 cast assigning umem->npgs.
    
    Fixes: bbff2f321a86 ("xsk: new descriptor addressing scheme")
    Signed-off-by: Kal Conley <kal.conley@xxxxxxxxxxx>
    Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
    Acked-by: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
    Link: https://lore.kernel.org/bpf/20230308174013.1114745-1-kal.conley@xxxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 4681e8e8ad943..02207e852d796 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -150,10 +150,11 @@ static int xdp_umem_account_pages(struct xdp_umem *umem)
 
 static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 {
-	u32 npgs_rem, chunk_size = mr->chunk_size, headroom = mr->headroom;
 	bool unaligned_chunks = mr->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
-	u64 npgs, addr = mr->addr, size = mr->len;
-	unsigned int chunks, chunks_rem;
+	u32 chunk_size = mr->chunk_size, headroom = mr->headroom;
+	u64 addr = mr->addr, size = mr->len;
+	u32 chunks_rem, npgs_rem;
+	u64 chunks, npgs;
 	int err;
 
 	if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) {
@@ -188,8 +189,8 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	if (npgs > U32_MAX)
 		return -EINVAL;
 
-	chunks = (unsigned int)div_u64_rem(size, chunk_size, &chunks_rem);
-	if (chunks == 0)
+	chunks = div_u64_rem(size, chunk_size, &chunks_rem);
+	if (!chunks || chunks > U32_MAX)
 		return -EINVAL;
 
 	if (!unaligned_chunks && chunks_rem)
@@ -202,7 +203,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	umem->headroom = headroom;
 	umem->chunk_size = chunk_size;
 	umem->chunks = chunks;
-	umem->npgs = (u32)npgs;
+	umem->npgs = npgs;
 	umem->pgs = NULL;
 	umem->user = NULL;
 	umem->flags = mr->flags;