Messages in this thread Patch in this message | | | From | Heinrich Schuchardt <> | Subject | [PATCH 1/1] drivers/usb/chipidea/debuc.c: avoid out of bound read | Date | Fri, 17 Apr 2015 08:04:13 +0200 |
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A string written by the user may not be zero terminated.
sscanf may read memory beyond the buffer if no zero byte is found.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> --- drivers/usb/chipidea/debug.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/chipidea/debug.c b/drivers/usb/chipidea/debug.c index dfb05ed..ef08af3 100644 --- a/drivers/usb/chipidea/debug.c +++ b/drivers/usb/chipidea/debug.c @@ -88,9 +88,13 @@ static ssize_t ci_port_test_write(struct file *file, const char __user *ubuf, char buf[32]; int ret; - if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count))) + count = min_t(size_t, sizeof(buf) - 1, count); + if (copy_from_user(buf, ubuf, count)) return -EFAULT; + /* sscanf requires a zero terminated string */ + buf[count] = 0; + if (sscanf(buf, "%u", &mode) != 1) return -EINVAL; -- 2.1.4
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