Patch "cpumap: Zero-initialise xdp_rxq_info struct before running XDP program" 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

    cpumap: Zero-initialise xdp_rxq_info struct before running XDP program

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:
     cpumap-zero-initialise-xdp_rxq_info-struct-before-ru.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 bd00ef5f4c01ae718ad8282f8d72c9304d0cd0d7
Author: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
Date:   Tue Mar 5 22:31:32 2024 +0100

    cpumap: Zero-initialise xdp_rxq_info struct before running XDP program
    
    [ Upstream commit 2487007aa3b9fafbd2cb14068f49791ce1d7ede5 ]
    
    When running an XDP program that is attached to a cpumap entry, we don't
    initialise the xdp_rxq_info data structure being used in the xdp_buff
    that backs the XDP program invocation. Tobias noticed that this leads to
    random values being returned as the xdp_md->rx_queue_index value for XDP
    programs running in a cpumap.
    
    This means we're basically returning the contents of the uninitialised
    memory, which is bad. Fix this by zero-initialising the rxq data
    structure before running the XDP program.
    
    Fixes: 9216477449f3 ("bpf: cpumap: Add the possibility to attach an eBPF program to cpumap")
    Reported-by: Tobias Böhm <tobias@xxxxxxxx>
    Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240305213132.11955-1-toke@xxxxxxxxxx
    Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 08a8e81027289..0508937048137 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -222,7 +222,7 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu,
 				    void **frames, int n,
 				    struct xdp_cpumap_stats *stats)
 {
-	struct xdp_rxq_info rxq;
+	struct xdp_rxq_info rxq = {};
 	struct xdp_buff xdp;
 	int i, nframes = 0;