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| author | Jann Horn <jannh@google.com> | 2025-02-12 21:15:16 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-21 15:57:15 +0300 |
| commit | db89b3bebd08ae0c8fd0c1f07454cef36ea06dc9 (patch) | |
| tree | 51e7f9b1a8b12675d72e937dd59c46ba20372623 /drivers/usb/class | |
| parent | 6abb510251e75f875797d8983a830e6731fa281c (diff) | |
| download | linux-db89b3bebd08ae0c8fd0c1f07454cef36ea06dc9.tar.xz | |
usb: cdc-acm: Fix handling of oversized fragments
commit 12e712964f41d05ae034989892de445781c46730 upstream.
If we receive an initial fragment of size 8 bytes which specifies a wLength
of 1 byte (so the reassembled message is supposed to be 9 bytes long), and
we then receive a second fragment of size 9 bytes (which is not supposed to
happen), we currently wrongly bypass the fragment reassembly code but still
pass the pointer to the acm->notification_buffer to
acm_process_notification().
Make this less wrong by always going through fragment reassembly when we
expect more fragments.
Before this patch, receiving an overlong fragment could lead to `newctrl`
in acm_process_notification() being uninitialized data (instead of data
coming from the device).
Cc: stable <stable@kernel.org>
Fixes: ea2583529cd1 ("cdc-acm: reassemble fragmented notifications")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/class')
| -rw-r--r-- | drivers/usb/class/cdc-acm.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 0d8900416287..c1d7d87b32cc 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -416,7 +416,7 @@ static void acm_ctrl_irq(struct urb *urb) expected_size = sizeof(struct usb_cdc_notification) + le16_to_cpu(dr->wLength); - if (current_size < expected_size) { + if (acm->nb_index != 0 || current_size < expected_size) { /* notification is transmitted fragmented, reassemble */ if (acm->nb_size < expected_size) { u8 *new_buffer; |