vt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()

2026-10-01T09:15:46Z

In paste_selection(), the loop copies min_t(unsigned int, vc_sel.buf_len - pasted,tty->receive_room) bytes per iteration into tty_ldisc_receive_buf() and increments pasted += count. Because the selection mutex (vc_sel.lock) is dropped inside the loop Whenever the line discipline buffer fills up and paste_selection() sleeps on tty->write_wait, a concurrent TIOCLINUX (TIOCL_SETSEL) ioctl can replace vc_sel.buffer with a shorter selection and reduce vc_sel.buf_len below pasted. When paste_selection() resumes, vc_sel.buf_len - pasted underflows as an unsigned integer to a large positive value, causing tty_ldisc_receive_buf(ld, vc_sel.buffer + pasted, NULL, count) to read up to 4094 bytes out-of-bounds past the newly allocated vc_sel.buffer. Fix this by terminating the loop when pasted >= vc_sel.buf_len. Kernel stack trace (Linux 7.3.0-rc3): ================================================================== BUG: KASAN: slab-out-of-bounds in n_tty_receive_buf_common+0xa01/0x1650 Read of size 4094 at addr ffff888101c58010 by task kworker/u17:1/65 Workqueue: events_unbound flush_to_ldisc Call Trace: dump_stack_lvl+0x70/0xa0 print_report+0x153/0x4c6 kasan_report+0xf1/0x120 kasan_check_range+0x11c/0x200 __asan_memcpy+0x29/0x70 n_tty_receive_buf_common+0xa01/0x1650 tty_ldisc_receive_buf+0x66/0x110 tty_port_default_receive_buf+0x6b/0xb0 flush_to_ldisc+0x1b4/0x410 process_one_work+0x6ff/0x1110 worker_thread+0x4a8/0xb70 kthread+0x307/0x3e0 ret_from_fork+0x3ed/0x680 ================================================================== Fixes: e8c75a30a23c ("vt: selection, push sel_lock up") Cc: stable Assisted-by: LLM Signed-off-by: Hui Peng Link: https://patch.msgid.link/20260919110041.3763078-1-benquike@gmail.com Signed-off-by: Greg Kroah-Hartman

tty: serial: mpc52xx_uart: move static declarations up.

2026-10-01T09:04:53Z

Avoid a compilation error so that they're not used before being declared. Fixes: 4d105880666a ("tty: serial: mpc52xx_uart: add bounds check for psc_num array index") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202609260356.tJWbd1WU-lkp@intel.com/ Signed-off-by: Rosen Penev Link: https://patch.msgid.link/20260927203501.14105-1-rosenp@gmail.com Signed-off-by: Greg Kroah-Hartman

kernel/git/stable/linux-stable.git/drivers/tty/vt/selection.c, branch master

vt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()

tty: serial: mpc52xx_uart: move static declarations up.