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| author | Jakob Koschel <jakobkoschel@gmail.com> | 2022-01-27 17:44:04 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-16 14:44:51 +0300 |
| commit | 2a45a6bd1e6d651770aafff57ab3e1d3bb0b42e0 (patch) | |
| tree | 1607d4049bbfd5c137e533359dd901d880dbdf95 | |
| parent | cdea6386dbb905f3ffc0ccd50e56604319949e87 (diff) | |
| download | linux-2a45a6bd1e6d651770aafff57ab3e1d3bb0b42e0.tar.xz | |
vt_ioctl: fix array_index_nospec in vt_setactivate
commit 61cc70d9e8ef5b042d4ed87994d20100ec8896d9 upstream.
array_index_nospec ensures that an out-of-bounds value is set to zero
on the transient path. Decreasing the value by one afterwards causes
a transient integer underflow. vsa.console should be decreased first
and then sanitized with array_index_nospec.
Kasper Acknowledgements: Jakob Koschel, Brian Johannesmeyer, Kaveh
Razavi, Herbert Bos, Cristiano Giuffrida from the VUSec group at VU
Amsterdam.
Co-developed-by: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
Signed-off-by: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Link: https://lore.kernel.org/r/20220127144406.3589293-1-jakobkoschel@gmail.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/vt/vt_ioctl.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c index cca8c84edfbc..f8fdc4ceaf7d 100644 --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -715,9 +715,9 @@ int vt_ioctl(struct tty_struct *tty, if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES) ret = -ENXIO; else { - vsa.console = array_index_nospec(vsa.console, - MAX_NR_CONSOLES + 1); vsa.console--; + vsa.console = array_index_nospec(vsa.console, + MAX_NR_CONSOLES); console_lock(); ret = vc_allocate(vsa.console); if (ret == 0) { |