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[RFC][PATCH 3/3] vsprintf: Add support for %pb and friends to vbin_printf()

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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

printk() allows a %pb to print out cpumasks. As it uses a pointer to
reference the mask it can be problematic for vbin_printf() to use, as the
referencing is done at a later time (via bstr_printf()). Instead of saving
the pointer to the cpumask, simply save the entire cpumask to the structure
and use that data for bstr_printf() to print it out.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 lib/vsprintf.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 1eb4c7bc3509..474d9ddaca6f 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2273,7 +2273,6 @@ static bool supported_bin_ptr(const char *fmt)
 	switch (fmt[0]) {
 	case 'R':
 	case 'r':
-	case 'b':
 	case 'M':
 	case 'm':
 	case 'I':
@@ -2397,6 +2396,16 @@ do {									\
 				str += sizeof(ptr);
 				break;
 			}
+			case 'b': {
+				unsigned long *mask = va_arg(args, void *);
+				int len = BITS_TO_LONGS(spec.field_width);
+
+				str = PTR_ALIGN(str, sizeof(u32));
+				if (str + len <= end)
+					memcpy(str, mask, len);
+				str += len;
+				break;
+			}
 			default:
 				save_arg(void *);
 			}
@@ -2552,11 +2561,18 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
 		}
 
 		case FORMAT_TYPE_PTR: {
+			unsigned long *tmp_ptr;
+			unsigned long *ptr;
 			const char *_fmt = fmt;
 			char tmp_fmt[2];
 
 			if (supported_bin_ptr(fmt)) {
 				switch (fmt[0]) {
+				case 'b': {
+					tmp_ptr = get_arg(void *);
+					ptr = (void *)&tmp_ptr;
+					break;
+				}
 				case 'F':
 				case 'f':
 					/*
@@ -2567,7 +2583,9 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
 					tmp_fmt[0] = 's' - ('f' - fmt[0]);
 					tmp_fmt[1] = 0;
 					_fmt = tmp_fmt;
-					break;
+					/* Fall through */
+				default:
+					ptr = get_arg(void *);
 				}
 			} else {
 				int len = sizeof(unsupported_str) + 1;
@@ -2583,8 +2601,10 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
 				/* Just show the pointer itself */
 				_fmt = "";
 				spec.field_width = -1;
+				ptr = get_arg(void *);
 			}
-			str = pointer(_fmt, str, end, get_arg(void *), spec);
+
+			str = pointer(_fmt, str, end, ptr, spec);
 
 			while (isalnum(*fmt))
 				fmt++;
-- 
2.8.1

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Thread

[RFC][PATCH 0/3] vsprintf: Do not dereference pointers in bstr_printf() Steven Rostedt <rostedt@goodmis.org> - 2016-06-29 22:20 +0200
  [RFC][PATCH 1/3] vsprintf: Prevent vbin_printf() from using dereferenced pointers Steven Rostedt <rostedt@goodmis.org> - 2016-06-29 22:20 +0200
  [RFC][PATCH 3/3] vsprintf: Add support for %pb and friends to vbin_printf() Steven Rostedt <rostedt@goodmis.org> - 2016-06-29 22:20 +0200
    Re: [RFC][PATCH 3/3] vsprintf: Add support for %pb and friends to  vbin_printf() Jiri Olsa <jolsa@redhat.com> - 2016-06-30 17:00 +0200
      Re: [RFC][PATCH 3/3] vsprintf: Add support for %pb and friends to  vbin_printf() Steven Rostedt <rostedt@goodmis.org> - 2016-06-30 17:50 +0200
  [RFC][PATCH 2/3] vsprintf: Add support for %pf and %pF to vbin_printf() Steven Rostedt <rostedt@goodmis.org> - 2016-06-29 22:20 +0200

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