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-rw-r--r--lib/vsprintf.c38
1 files changed, 30 insertions, 8 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index c150d3dafff4..d3023df8477f 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -936,6 +936,8 @@ char *uuid_string(char *buf, char *end, const u8 *addr,
return string(buf, end, uuid, spec);
}
+int kptr_restrict = 1;
+
/*
* Show a '%p' thing. A kernel extension is that the '%p' is followed
* by an extra set of alphanumeric characters that are extended format
@@ -979,6 +981,7 @@ char *uuid_string(char *buf, char *end, const u8 *addr,
* Implements a "recursive vsnprintf".
* Do not use this feature without some mechanism to verify the
* correctness of the format string and va_list arguments.
+ * - 'K' For a kernel pointer that should be hidden from unprivileged users
*
* Note: The difference between 'S' and 'F' is that on ia64 and ppc64
* function pointers are really function descriptors, which contain a
@@ -1035,6 +1038,25 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
return buf + vsnprintf(buf, end - buf,
((struct va_format *)ptr)->fmt,
*(((struct va_format *)ptr)->va));
+ case 'K':
+ /*
+ * %pK cannot be used in IRQ context because its test
+ * for CAP_SYSLOG would be meaningless.
+ */
+ if (in_irq() || in_serving_softirq() || in_nmi()) {
+ if (spec.field_width == -1)
+ spec.field_width = 2 * sizeof(void *);
+ return string(buf, end, "pK-error", spec);
+ } else if ((kptr_restrict == 0) ||
+ (kptr_restrict == 1 &&
+ has_capability_noaudit(current, CAP_SYSLOG)))
+ break;
+
+ if (spec.field_width == -1) {
+ spec.field_width = 2 * sizeof(void *);
+ spec.flags |= ZEROPAD;
+ }
+ return number(buf, end, 0, spec);
}
spec.flags |= SMALL;
if (spec.field_width == -1) {
@@ -1451,7 +1473,7 @@ EXPORT_SYMBOL(vsnprintf);
* @args: Arguments for the format string
*
* The return value is the number of characters which have been written into
- * the @buf not including the trailing '\0'. If @size is <= 0 the function
+ * the @buf not including the trailing '\0'. If @size is == 0 the function
* returns 0.
*
* Call this function if you are already dealing with a va_list.
@@ -1465,7 +1487,11 @@ int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
i = vsnprintf(buf, size, fmt, args);
- return (i >= size) ? (size - 1) : i;
+ if (likely(i < size))
+ return i;
+ if (size != 0)
+ return size - 1;
+ return 0;
}
EXPORT_SYMBOL(vscnprintf);
@@ -1513,14 +1539,10 @@ int scnprintf(char *buf, size_t size, const char *fmt, ...)
int i;
va_start(args, fmt);
- i = vsnprintf(buf, size, fmt, args);
+ i = vscnprintf(buf, size, fmt, args);
va_end(args);
- if (likely(i < size))
- return i;
- if (size != 0)
- return size - 1;
- return 0;
+ return i;
}
EXPORT_SYMBOL(scnprintf);