console: Fix console name size mismatch

commit 30a22c215a0007603ffc08021f2e8b64018517dd upstream.

commit 6ae9200f2cab7 ("enlarge console.name") increased the storage
for the console name to 16 bytes, but not the corresponding
struct console_cmdline::name storage. Console names longer than
8 bytes cause read beyond end-of-string and failure to match
console; I'm not sure if there are other unexpected consequences.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[lizf: Backported to 3.4:
 - adjust filename
 - s/c->name/console_cmdline[i].name/]
Signed-off-by: Zefan Li <lizefan@huawei.com>

diff --git a/kernel/printk.c b/kernel/printk.c
index 544c0215939a831d723d452d31aac31a11bc037d..cb72d9c406cd4655fe9f8f272be88d6d7339bf4e 100644 (file)
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -126,7 +126,7 @@ static struct console *exclusive_console;
  */
 struct console_cmdline
 {
-       char    name[8];                        /* Name of the driver       */
+       char    name[16];                       /* Name of the driver       */
        int     index;                          /* Minor dev. to use        */
        char    *options;                       /* Options for the driver   */
 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
@@ -1498,6 +1498,7 @@ void register_console(struct console *newcon)
         */
        for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
                        i++) {
+               BUILD_BUG_ON(sizeof(console_cmdline[i].name) != sizeof(newcon->name));
                if (strcmp(console_cmdline[i].name, newcon->name) != 0)
                        continue;
                if (newcon->index >= 0 &&