xsk: fix an integer overflow in xp_create_and_assign_umem()

JIRA: https://issues.redhat.com/browse/RHEL-96605
JIRA: https://issues.redhat.com/browse/RHEL-87917
CVE: CVE-2025-21997

commit 559847f
Author: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
Date:   Thu Mar 13 08:50:08 2025 +0000

    xsk: fix an integer overflow in xp_create_and_assign_umem()

    Since the i and pool->chunk_size variables are of type 'u32',
    their product can wrap around and then be cast to 'u64'.
    This can lead to two different XDP buffers pointing to the same
    memory area.

    Found by InfoTeCS on behalf of Linux Verification Center
    (linuxtesting.org) with SVACE.

    Fixes: 94033cd ("xsk: Optimize for aligned case")
    Cc: stable@vger.kernel.org
    Signed-off-by: Ilia Gavrilov <Ilia.Gavrilov@infotecs.ru>
    Link: https://patch.msgid.link/20250313085007.3116044-1-Ilia.Gavrilov@infotecs.ru
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Signed-off-by: Felix Maurer <fmaurer@redhat.com>

Author: fmaurer-rh

net/xdp/xsk_buff_pool.c

@@ -106,7 +106,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
 		if (pool->unaligned)
 			pool->free_heads[i] = xskb;
 		else
-			xp_init_xskb_addr(xskb, pool, i * pool->chunk_size);
+			xp_init_xskb_addr(xskb, pool, (u64)i * pool->chunk_size);
 	}
 
 	return pool;