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authorNicolas Pitre <nico@fluxnic.net>2020-03-29 00:32:42 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-04-23 16:46:31 +0300
commit2717769e204e83e65b8819c5e2ef3e5b6639b270 (patch)
tree8086e490f73e49d5c5bb5bb82fb4890ce4d48be6 /drivers/tty
parentabf42d2f333b21bf8d33b2fbb8a85fa62037ac01 (diff)
downloadlinux-2717769e204e83e65b8819c5e2ef3e5b6639b270.tar.xz
vt: don't hardcode the mem allocation upper bound
The code in vc_do_resize() bounds the memory allocation size to avoid exceeding MAX_ORDER down the kzalloc() call chain and generating a runtime warning triggerable from user space. However, not only is it unwise to use a literal value here, but MAX_ORDER may also be configurable based on CONFIG_FORCE_MAX_ZONEORDER. Let's use KMALLOC_MAX_SIZE instead. Note that prior commit bb1107f7c605 ("mm, slab: make sure that KMALLOC_MAX_SIZE will fit into MAX_ORDER") the KMALLOC_MAX_SIZE value could not be relied upon. Signed-off-by: Nicolas Pitre <nico@fluxnic.net> Cc: <stable@vger.kernel.org> # v4.10+ Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.2003281702410.2671@knanqh.ubzr Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/vt/vt.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 3272759b1f3c..e5ffed795e4c 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1207,7 +1207,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
if (new_cols == vc->vc_cols && new_rows == vc->vc_rows)
return 0;
- if (new_screen_size > (4 << 20))
+ if (new_screen_size > KMALLOC_MAX_SIZE)
return -EINVAL;
newscreen = kzalloc(new_screen_size, GFP_USER);
if (!newscreen)