In of_modalias(), we can get passed the str and len parameters which would cause a kernel oops in vsnprintf() since it only allows passing a NULL ptr when the length is also 0. Also, we need to filter out the negative values of the len parameter as these will result in a really huge buffer since snprintf() takes size_t parameter while ours is ssize_t... Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool. Signed-off-by: Sergey Shtylyov <s.shtylyov@xxxxxx> --- The patch is against the for-next branch of Rob Herring's linux-git repo... drivers/of/module.c | 8 ++++++++ 1 file changed, 8 insertions(+) Index: linux/drivers/of/module.c =================================================================== --- linux.orig/drivers/of/module.c +++ linux/drivers/of/module.c @@ -16,6 +16,14 @@ ssize_t of_modalias(const struct device_ ssize_t csize; ssize_t tsize; + /* + * Prevent a kernel oops in vsnprintf() -- it only allows passing a + * NULL ptr when the length is also 0. Also filter out the negative + * lengths... + */ + if ((len > 0 && !str) || len < 0) + return -EINVAL; + /* Name & Type */ /* %p eats all alphanum characters, so %c must be used here */ csize = snprintf(str, len, "of:N%pOFn%c%s", np, 'T',
