From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
[ Upstream commit 3df7546fc03b8f004eee0b9e3256369f7d096685 ]
syzbot is reporting too large allocation warning at tomoyo_write_control(), for one can write a very very long line without new line character. To fix this warning, I use __GFP_NOWARN rather than checking for KMALLOC_MAX_SIZE, for practically a valid line should be always shorter than 32KB where the "too small to fail" memory-allocation rule applies.
One might try to write a valid line that is longer than 32KB, but such request will likely fail with -ENOMEM. Therefore, I feel that separately returning -EINVAL when a line is longer than KMALLOC_MAX_SIZE is redundant. There is no need to distinguish over-32KB and over-KMALLOC_MAX_SIZE.
Reported-by: syzbot+7536f77535e5210a5c76@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=7536f77535e5210a5c76 Reported-by: Leo Stone leocstone@gmail.com Closes: https://lkml.kernel.org/r/20241216021459.178759-2-leocstone@gmail.com Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Sasha Levin sashal@kernel.org --- security/tomoyo/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c index a7af085550b2d..5f1cdd0af115d 100644 --- a/security/tomoyo/common.c +++ b/security/tomoyo/common.c @@ -2664,7 +2664,7 @@ ssize_t tomoyo_write_control(struct tomoyo_io_buffer *head,
if (head->w.avail >= head->writebuf_size - 1) { const int len = head->writebuf_size * 2; - char *cp = kzalloc(len, GFP_NOFS); + char *cp = kzalloc(len, GFP_NOFS | __GFP_NOWARN);
if (!cp) { error = -ENOMEM;