Messages in this thread Patch in this message |  | | From | Petr Mladek <> | Subject | [PATCH v4 7/9] vsprintf: Factor out %pO handler as kobject_string() | Date | Wed, 4 Apr 2018 10:58:41 +0200 |
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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 | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index f20eaa3f0092..3551b7957d9e 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1772,6 +1772,19 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, } static noinline_for_stack +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); + } + + WARN_ONCE(1, "Unsupported pointer format specifier: %%pO%c\n", fmt[1]); + return buf; +} + +static noinline_for_stack char *pointer_string(char *buf, char *end, const void *ptr, struct printf_spec spec) { @@ -1982,10 +1995,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'G': return flags_string(buf, end, ptr, 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
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