Messages in this thread Patch in this message | | | From | Petr Mladek <> | Subject | [PATCH v5 08/11] vsprintf: Factor out %pO handler as kobject_string() | Date | Wed, 25 Apr 2018 13:12:48 +0200 |
| |
Move code from the long pointer() function. We are going to add a check for the access to the address that will make it even more complicated.
Also it is better to warn about unknown specifier instead of falling back to the %p behavior. It will help people to understand what is going wrong. They expect some device node names and not a pointer in this situation.
In fact, this avoids leaking the address when invalid %pO format specifier is used. The old code fallen back to printing the non-hashed value.
Fixes: commit 7b1924a1d930eb27f ("vsprintf: add printk specifier %px") Signed-off-by: Petr Mladek <pmladek@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tobin Harding <me@tobin.cc> Cc: Kees Cook <keescook@chromium.org> --- lib/vsprintf.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index e58436ef9f7f..3536796c483c 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1769,6 +1769,17 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, return widen_string(buf, buf - buf_start, end, spec); } +static char *kobject_string(char *buf, char *end, void *ptr, + struct printf_spec spec, const char *fmt) +{ + switch (fmt[1]) { + case 'F': + return device_node_string(buf, end, ptr, spec, fmt + 1); + } + + return valid_string(buf, end, "(%pO?)", spec); +} + /* * Show a '%p' thing. A kernel extension is that the '%p' is followed * by an extra set of alphanumeric characters that are extended format @@ -1962,10 +1973,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'G': return flags_string(buf, end, ptr, spec, fmt); case 'O': - switch (fmt[1]) { - case 'F': - return device_node_string(buf, end, ptr, spec, fmt + 1); - } + return kobject_string(buf, end, ptr, spec, fmt); case 'x': return pointer_string(buf, end, ptr, spec); } -- 2.13.6
| |