From: Daniel Starke daniel.starke@siemens.com
stable inclusion from stable-v5.10.114 commit 95b267271a7db5e6884de342ab0f2ccf77e220be category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5IY1V
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit ff9166c623704337bd6fe66fce2838d9768a6634 upstream.
n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010. See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.a... The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.4.4.2 states that any received unnumbered acknowledgment (UA) with its poll/final (PF) bit set to 0 shall be discarded. Currently, all UA frame are handled in the same way regardless of the PF bit. This does not comply with the standard. Remove the UA case in gsm_queue() to process only UA frames with PF bit set to 1 to abide the standard.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Cc: stable@vger.kernel.org Signed-off-by: Daniel Starke daniel.starke@siemens.com Link: https://lore.kernel.org/r/20220414094225.4527-20-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- drivers/tty/n_gsm.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index cce1a8bf43db..afcd41e6373f 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1817,7 +1817,6 @@ static void gsm_queue(struct gsm_mux *gsm) gsm_response(gsm, address, UA); gsm_dlci_close(dlci); break; - case UA: case UA|PF: if (cr == 0 || dlci == NULL) break;