diff options
| author | Sven Schnelle <svens@linux.ibm.com> | 2022-12-09 12:27:36 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-19 15:04:56 +0100 |
| commit | db4df8e9d79e7d37732c1a1b560958e8dadfefa1 (patch) | |
| tree | e5fbbb5a13502bd512b81e7503e998e617438d6f /drivers/tty/tty_io.c | |
| parent | dt-bindings: serial: qcom,msm-uart: Convert to DT schema (diff) | |
| download | linux-db4df8e9d79e7d37732c1a1b560958e8dadfefa1.tar.xz linux-db4df8e9d79e7d37732c1a1b560958e8dadfefa1.zip | |
tty: fix out-of-bounds access in tty_driver_lookup_tty()
When specifying an invalid console= device like console=tty3270,
tty_driver_lookup_tty() returns the tty struct without checking
whether index is a valid number.
To reproduce:
qemu-system-x86_64 -enable-kvm -nographic -serial mon:stdio \
-kernel ../linux-build-x86/arch/x86/boot/bzImage \
-append "console=ttyS0 console=tty3270"
This crashes with:
[ 0.770599] BUG: kernel NULL pointer dereference, address: 00000000000000ef
[ 0.771265] #PF: supervisor read access in kernel mode
[ 0.771773] #PF: error_code(0x0000) - not-present page
[ 0.772609] Oops: 0000 [#1] PREEMPT SMP PTI
[ 0.774878] RIP: 0010:tty_open+0x268/0x6f0
[ 0.784013] chrdev_open+0xbd/0x230
[ 0.784444] ? cdev_device_add+0x80/0x80
[ 0.784920] do_dentry_open+0x1e0/0x410
[ 0.785389] path_openat+0xca9/0x1050
[ 0.785813] do_filp_open+0xaa/0x150
[ 0.786240] file_open_name+0x133/0x1b0
[ 0.786746] filp_open+0x27/0x50
[ 0.787244] console_on_rootfs+0x14/0x4d
[ 0.787800] kernel_init_freeable+0x1e4/0x20d
[ 0.788383] ? rest_init+0xc0/0xc0
[ 0.788881] kernel_init+0x11/0x120
[ 0.789356] ret_from_fork+0x22/0x30
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20221209112737.3222509-2-svens@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 3149114bf130..36fb945fdad4 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1224,14 +1224,16 @@ static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, { struct tty_struct *tty; - if (driver->ops->lookup) + if (driver->ops->lookup) { if (!file) tty = ERR_PTR(-EIO); else tty = driver->ops->lookup(driver, file, idx); - else + } else { + if (idx >= driver->num) + return ERR_PTR(-EINVAL); tty = driver->ttys[idx]; - + } if (!IS_ERR(tty)) tty_kref_get(tty); return tty; |