From 8f0e62398ac94e3485143f4e7ee37e92bf8e09f2 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sat, 25 May 2024 16:56:02 +0200 Subject: [PATCH] 5.10-stable patches added patches: series tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch --- queue-5.10/series | 1 + ...ssible-out-of-bounds-in-gsm0_receive.patch | 65 +++++++++++++++++++ 2 files changed, 66 insertions(+) create mode 100644 queue-5.10/series create mode 100644 queue-5.10/tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch diff --git a/queue-5.10/series b/queue-5.10/series new file mode 100644 index 00000000000..ae483180dca --- /dev/null +++ b/queue-5.10/series @@ -0,0 +1 @@ +tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch diff --git a/queue-5.10/tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch b/queue-5.10/tty-n_gsm-fix-possible-out-of-bounds-in-gsm0_receive.patch new file mode 100644 index 00000000000..759f9fb0833 --- /dev/null +++ b/queue-5.10/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 +Date: Wed, 24 Apr 2024 07:48:41 +0200 +Subject: tty: n_gsm: fix possible out-of-bounds in gsm0_receive() + +From: Daniel Starke + +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 +Link: https://lore.kernel.org/r/20240424054842.7741-1-daniel.starke@siemens.com +Signed-off-by: Greg Kroah-Hartman +--- + 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 +@@ -2082,8 +2082,12 @@ 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; +@@ -2176,7 +2180,7 @@ 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 -- 2.47.2