From: Bernard Pidoux f6bvp@free.fr
stable inclusion from stable-v5.10.140 commit de3deadd11987070788b48825bec4647458b988d category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I63FTT
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 3c53cd65dece47dd1f9d3a809f32e59d1d87b2b8 ]
Commit 3b3fd068c56e3fbea30090859216a368398e39bf added NULL check for `rose_loopback_neigh->dev` in rose_loopback_timer() but omitted to check rose_loopback_neigh->loopback.
It thus prevents *all* rose connect.
The reason is that a special rose_neigh loopback has a NULL device.
/proc/net/rose_neigh illustrates it via rose_neigh_show() function : [...] seq_printf(seq, "%05d %-9s %-4s %3d %3d %3s %3s %3lu %3lu", rose_neigh->number, (rose_neigh->loopback) ? "RSLOOP-0" : ax2asc(buf, &rose_neigh->callsign), rose_neigh->dev ? rose_neigh->dev->name : "???", rose_neigh->count,
/proc/net/rose_neigh displays special rose_loopback_neigh->loopback as callsign RSLOOP-0:
addr callsign dev count use mode restart t0 tf digipeaters 00001 RSLOOP-0 ??? 1 2 DCE yes 0 0
By checking rose_loopback_neigh->loopback, rose_rx_call_request() is called even in case rose_loopback_neigh->dev is NULL. This repairs rose connections.
Verification with rose client application FPAC:
FPAC-Node v 4.1.3 (built Aug 5 2022) for LINUX (help = h) F6BVP-4 (Commands = ?) : u Users - AX.25 Level 2 sessions : Port Callsign Callsign AX.25 state ROSE state NetRom status axudp F6BVP-5 -> F6BVP-9 Connected Connected ---------
Fixes: 3b3fd068c56e ("rose: Fix Null pointer dereference in rose_send_frame()") Signed-off-by: Bernard Pidoux f6bvp@free.fr Suggested-by: Francois Romieu romieu@fr.zoreil.com Cc: Thomas DL9SAU Osterried thomas@osterried.de Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Wei Li liwei391@huawei.com --- net/rose/rose_loopback.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/rose/rose_loopback.c b/net/rose/rose_loopback.c index 11c45c8c6c16..036d92c0ad79 100644 --- a/net/rose/rose_loopback.c +++ b/net/rose/rose_loopback.c @@ -96,7 +96,8 @@ static void rose_loopback_timer(struct timer_list *unused) }
if (frametype == ROSE_CALL_REQUEST) { - if (!rose_loopback_neigh->dev) { + if (!rose_loopback_neigh->dev && + !rose_loopback_neigh->loopback) { kfree_skb(skb); continue; }