[PATCH v2]tty:vt: Add NULL check to return value of kzalloc()

From: Wang YanQing
Date: Mon Oct 28 2013 - 21:19:23 EST


In extreme situation kzalloc in con_init may
return NULL, so we should check it to prevent
OOPS!

Signed-off-by: Wang YanQing <udknight@xxxxxxxxx>
Reported-by: RUC_SoftSec <rucsoftsec@xxxxxxxxx>
---
Changes:
v1-v2:
1:fix warning and error reported by scripts/checkpatch.pl

drivers/tty/vt/vc_screen.c | 6 ++++--
drivers/tty/vt/vt.c | 12 ++++++++++++
2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
index d7799de..e0de4bc 100644
--- a/drivers/tty/vt/vc_screen.c
+++ b/drivers/tty/vt/vc_screen.c
@@ -662,7 +662,9 @@ int __init vcs_init(void)

device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
- for (i = 0; i < MIN_NR_CONSOLES; i++)
- vcs_make_sysfs(i);
+ for (i = 0; i < MIN_NR_CONSOLES; i++) {
+ if (vc_cons[i].d)
+ vcs_make_sysfs(i);
+ }
return 0;
}
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 740202d..8f490e9 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -2885,6 +2885,8 @@ static int __init con_init(void)

for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) {
vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), GFP_NOWAIT);
+ if (vc == NULL)
+ break;
INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
tty_port_init(&vc->port);
visual_init(vc, currcons, 1);
@@ -2892,8 +2894,18 @@ static int __init con_init(void)
vc_init(vc, vc->vc_rows, vc->vc_cols,
currcons || !vc->vc_sw->con_save_screen);
}
+ if (currcons < MIN_NR_CONSOLES)
+ pr_warn("Console: vt %d-%d initialization failed!\n",
+ currcons, MIN_NR_CONSOLES - 1);
+
currcons = fg_console = 0;
master_display_fg = vc = vc_cons[currcons].d;
+
+ if (vc == NULL) {
+ pr_warn("Console: no avaiable vt!\n");
+ console_unlock();
+ return 0;
+ }
set_origin(vc);
save_screen(vc);
gotoxy(vc, vc->vc_x, vc->vc_y);
--
1.7.12.4.dirty
--
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