From: Alexander Shishkin Date: Tue, 22 Dec 2015 15:25:21 +0000 (+0200) Subject: stm class: Prevent user-controllable allocations X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=f08b18266c7116e2ec6885dd53a928f580060a71;p=openwrt%2Fstaging%2Fblogic.git stm class: Prevent user-controllable allocations Currently, the character device write method allocates a temporary buffer for user's data, but the user's data size is not sanitized and can cause arbitrarily large allocations via kzalloc() or an integer overflow that will then result in overwriting kernel memory. This patch trims the input buffer size to avoid these issues. Reported-by: Sasha Levin Signed-off-by: Alexander Shishkin Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index 40a8b79ab7db..aef8ddb24451 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -406,6 +406,9 @@ static ssize_t stm_char_write(struct file *file, const char __user *buf, char *kbuf; int err; + if (count + 1 > PAGE_SIZE) + count = PAGE_SIZE - 1; + /* * if no m/c have been assigned to this writer up to this * point, use "default" policy entry