4.19-stable patches

added patches:
	series
	tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch

diff --git a/queue-4.19/series b/queue-4.19/series
new file mode 100644 (file)
index 0000000..ae48318
--- /dev/null
+++ b/queue-4.19/series
@@ -0,0 +1 @@
+tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch

diff --git a/queue-4.19/tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch b/queue-4.19/tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch
new file mode 100644 (file)
index 0000000..c87b763
--- /dev/null
+++ b/queue-4.19/tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch
@@ -0,0 +1,65 @@
+From 47388e807f85948eefc403a8a5fdc5b406a65d5a Mon Sep 17 00:00:00 2001
+From: Daniel Starke <daniel.starke@siemens.com>
+Date: Wed, 24 Apr 2024 07:48:41 +0200
+Subject: tty: n_gsm: fix possible out-of-bounds in gsm0_receive()
+
+From: Daniel Starke <daniel.starke@siemens.com>
+
+commit 47388e807f85948eefc403a8a5fdc5b406a65d5a upstream.
+
+Assuming the following:
+- side A configures the n_gsm in basic option mode
+- side B sends the header of a basic option mode frame with data length 1
+- side A switches to advanced option mode
+- side B sends 2 data bytes which exceeds gsm->len
+  Reason: gsm->len is not used in advanced option mode.
+- side A switches to basic option mode
+- side B keeps sending until gsm0_receive() writes past gsm->buf
+  Reason: Neither gsm->state nor gsm->len have been reset after
+  reconfiguration.
+
+Fix this by changing gsm->count to gsm->len comparison from equal to less
+than. Also add upper limit checks against the constant MAX_MRU in
+gsm0_receive() and gsm1_receive() to harden against memory corruption of
+gsm->len and gsm->mru.
+
+All other checks remain as we still need to limit the data according to the
+user configuration and actual payload size.
+
+Reported-by: j51569436@gmail.com
+Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218708
+Tested-by: j51569436@gmail.com
+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/20240424054842.7741-1-daniel.starke@siemens.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/n_gsm.c |    8 ++++++--
+ 1 file changed, 6 insertions(+), 2 deletions(-)
+
+--- a/drivers/tty/n_gsm.c
++++ b/drivers/tty/n_gsm.c
+@@ -1972,8 +1972,12 @@ static void gsm0_receive(struct gsm_mux
+               break;
+       case GSM_DATA:          /* Data */
+               gsm->buf[gsm->count++] = c;
+-              if (gsm->count == gsm->len)
++              if (gsm->count >= MAX_MRU) {
++                      gsm->bad_size++;
++                      gsm->state = GSM_SEARCH;
++              } else if (gsm->count >= gsm->len) {
+                       gsm->state = GSM_FCS;
++              }
+               break;
+       case GSM_FCS:           /* FCS follows the packet */
+               gsm->received_fcs = c;
+@@ -2053,7 +2057,7 @@ static void gsm1_receive(struct gsm_mux
+               gsm->state = GSM_DATA;
+               break;
+       case GSM_DATA:          /* Data */
+-              if (gsm->count > gsm->mru) {    /* Allow one for the FCS */
++              if (gsm->count > gsm->mru || gsm->count > MAX_MRU) {    /* Allow one for the FCS */
+                       gsm->state = GSM_OVERRUN;
+                       gsm->bad_size++;
+               } else