kernel/linux.git/drivers/usb/class/usblp.c, branch v5.10.264

usb: usblp: fix uninitialized heap leak via LPGETSTATUS ioctl

2026-06-01T15:29:22+00:00

commit b38e53cbfb9d84732e5984fbd73e128d592415c5 upstream. Just like in a previous problem in this driver, usblp_ctrl_msg() will collapse the usb_control_msg() return value to 0/-errno, discarding the actual number of bytes transferred. Ideally that short command should be detected and error out, but many printers are known to send "incorrect" responses back so we can't just do that. statusbuf is kmalloc(8) at probe time and never filled before the first LPGETSTATUS ioctl. usblp_read_status() requests 1 byte. If a malicious printer responds with zero bytes, *statusbuf is one byte of stale kmalloc heap, sign-extended into the local int status, which the LPGETSTATUS path then copy_to_user()s directly to the ioctl caller. Fix this all by just zapping out the memory buffer when allocated at probe time. If a later call does a short read, the data will be identical to what the device sent it the last time, so there is no "leak" of information happening. Cc: Pete Zaitcev Assisted-by: gkh_clanker_t1000 Cc: stable Link: https://patch.msgid.link/2026042011-shredder-savage-48c6@gregkh Signed-off-by: Greg Kroah-Hartman

usb: usblp: fix heap leak in IEEE 1284 device ID via short response

2026-06-01T15:29:22+00:00

commit 7a400c6fe3617e31e690e3f7ca37bb335e0498f3 upstream. usblp_ctrl_msg() collapses the usb_control_msg() return value to 0/-errno, discarding the actual number of bytes transferred. A broken printer can complete the GET_DEVICE_ID control transfer short and the driver has no way to know. usblp_cache_device_id_string() reads the 2-byte big-endian length prefix from the response and trusts it (clamped only to the buffer bounds). The buffer is kmalloc(1024) at probe time. A device that sends exactly two bytes (e.g. 0x03 0xFF, claiming a 1023-byte ID) leaves device_id_string[2..1022] holding stale kmalloc heap. That stale data is then exposed: - via the ieee1284_id sysfs attribute (sprintf("%s", buf+2), truncated at the first NUL in the stale heap), and - via the IOCNR_GET_DEVICE_ID ioctl, which copy_to_user()s the full claimed length regardless of NULs, up to 1021 bytes of uninitialized heap, with the leak size chosen by the device. Fix this up by just zapping the buffer with zeros before each request sent to the device. Cc: Pete Zaitcev Assisted-by: gkh_clanker_t1000 Cc: stable Link: https://patch.msgid.link/2026042002-unicorn-greedily-3c63@gregkh Signed-off-by: Greg Kroah-Hartman

USB: usblp: return error when setting unsupported protocol

2025-02-01T17:22:22+00:00

commit 7a3d76a0b60b3f6fc3375e4de2174bab43f64545 upstream. Fix the regression introduced by commit d8c6edfa3f4e ("USB: usblp: don't call usb_set_interface if there's a single alt"), which causes that unsupported protocols can also be set via ioctl when the num_altsetting of the device is 1. Move the check for protocol support to the earlier stage. Fixes: d8c6edfa3f4e ("USB: usblp: don't call usb_set_interface if there's a single alt") Cc: stable Signed-off-by: Jun Yan Link: https://lore.kernel.org/r/20241212143852.671889-1-jerrysteve1101@gmail.com Signed-off-by: Greg Kroah-Hartman

USB: usblp: fix a hang in poll() if disconnected

2021-03-17T16:06:29+00:00

commit 9de2c43acf37a17dc4c69ff78bb099b80fb74325 upstream. Apparently an application that opens a device and calls select() on it, will hang if the decice is disconnected. It's a little surprising that we had this bug for 15 years, but apparently nobody ever uses select() with a printer: only write() and read(), and those work fine. Well, you can also select() with a timeout. The fix is modeled after devio.c. A few other drivers check the condition first, then do not add the wait queue in case the device is disconnected. We doubt that's completely race-free. So, this patch adds the process first, then locks properly and checks for the disconnect. Reviewed-by: Zqiang Signed-off-by: Pete Zaitcev Cc: stable Link: https://lore.kernel.org/r/20210303221053.1cf3313e@suzdal.zaitcev.lan Signed-off-by: Greg Kroah-Hartman

USB: usblp: don't call usb_set_interface if there's a single alt

2021-02-10T08:29:10+00:00

commit d8c6edfa3f4ee0d45d7ce5ef18d1245b78774b9d upstream. Some devices, such as the Winbond Electronics Corp. Virtual Com Port (Vendor=0416, ProdId=5011), lockup when usb_set_interface() or usb_clear_halt() are called. This device has only a single altsetting, so it should not be necessary to call usb_set_interface(). Acked-by: Pete Zaitcev Signed-off-by: Jeremy Figgins Link: https://lore.kernel.org/r/YAy9kJhM/rG8EQXC@watson Cc: stable Signed-off-by: Greg Kroah-Hartman

USB: usblp: fix DMA to stack

2021-01-12T19:18:20+00:00

commit 020a1f453449294926ca548d8d5ca970926e8dfd upstream. Stack-allocated buffers cannot be used for DMA (on all architectures). Replace the HP-channel macro with a helper function that allocates a dedicated transfer buffer so that it can continue to be used with arguments from the stack. Note that the buffer is cleared on allocation as usblp_ctrl_msg() returns success also on short transfers (the buffer is only used for debugging). Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210104145302.2087-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

usblp: fix race between disconnect() and read()

2020-09-17T16:45:30+00:00

read() needs to check whether the device has been disconnected before it tries to talk to the device. Signed-off-by: Oliver Neukum Reported-by: syzbot+be5b5f86a162a6c281e6@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20200917103427.15740-1-oneukum@suse.com Cc: stable Signed-off-by: Greg Kroah-Hartman

usblp: poison URBs upon disconnect

2020-05-13T12:20:00+00:00

syzkaller reported an URB that should have been killed to be active. We do not understand it, but this should fix the issue if it is real. Signed-off-by: Oliver Neukum Reported-by: syzbot+be5b5f86a162a6c281e6@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20200507085806.5793-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman

USB: usblp: fix use-after-free on disconnect

2019-10-15T18:19:19+00:00

A recent commit addressing a runtime PM use-count regression, introduced a use-after-free by not making sure we held a reference to the struct usb_interface for the lifetime of the driver data. Fixes: 9a31535859bf ("USB: usblp: fix runtime PM after driver unbind") Cc: stable Reported-by: syzbot+cd24df4d075c319ebfc5@syzkaller.appspotmail.com Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20191015175522.18490-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

USB: usblp: fix runtime PM after driver unbind

2019-10-04T12:38:45+00:00

Since commit c2b71462d294 ("USB: core: Fix bug caused by duplicate interface PM usage counter") USB drivers must always balance their runtime PM gets and puts, including when the driver has already been unbound from the interface. Leaving the interface with a positive PM usage counter would prevent a later bound driver from suspending the device. Fixes: c2b71462d294 ("USB: core: Fix bug caused by duplicate interface PM usage counter") Cc: stable Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20191001084908.2003-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman