path: root/lib/vsprintf.c
diff options
authorKees Cook <>2011-03-22 16:34:22 -0700
committerLinus Torvalds <>2011-03-22 17:44:12 -0700
commit9f36e2c448007b54851e7e4fa48da97d1477a175 (patch)
tree2fa0ad88c75184dc79b28c287c853e97f779bf1f /lib/vsprintf.c
parentfe3d8ad31cf51b062bbb8a9609eeb1d0c41a7f30 (diff)
printk: use %pK for /proc/kallsyms and /proc/modules
In an effort to reduce kernel address leaks that might be used to help target kernel privilege escalation exploits, this patch uses %pK when displaying addresses in /proc/kallsyms, /proc/modules, and /sys/module/*/sections/*. Note that this changes %x to %p, so some legitimately 0 values in /proc/kallsyms would have changed from 00000000 to "(null)". To avoid this, "(null)" is not used when using the "K" format. Anything that was already successfully parsing "(null)" in addition to full hex digits should have no problem with this change. (Thanks to Joe Perches for the suggestion.) Due to the %x to %p, "void *" casts are needed since these addresses are already "unsigned long" everywhere internally, due to their starting life as ELF section offsets. Signed-off-by: Kees Cook <> Cc: Eugene Teo <> Cc: Dan Rosenberg <> Cc: Rusty Russell <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'lib/vsprintf.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 070d134eef71..ac444ff01658 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -991,7 +991,7 @@ static noinline_for_stack
char *pointer(const char *fmt, char *buf, char *end, void *ptr,
struct printf_spec spec)
- if (!ptr) {
+ if (!ptr && *fmt != 'K') {
* Print (null) with the same width as a pointer so it makes
* tabular output look nice.