vsprintf.c: Always enable CONFIG_SYS_VSNPRINTF

Enabling this function always removes some class of string saftey issues.
The size change here in general is about 400 bytes and this seems a reasonable
trade-off.

Cc: Peng Fan <peng.fan@nxp.com>
Cc: Peter Robinson <pbrobinson@gmail.com>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Adrian Alonso <aalonso@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tom Rini <trini@konsulko.com>

README

@@ -890,15 +890,6 @@ The following options need to be configured:
 		'Sane' compilers will generate smaller code if
 		CONFIG_PRE_CON_BUF_SZ is a power of 2
 
-- Safe printf() functions
-		Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
-		the printf() functions. These are defined in
-		include/vsprintf.h and include snprintf(), vsnprintf() and
-		so on. Code size increase is approximately 300-500 bytes.
-		If this option is not given then these functions will
-		silently discard their buffer size argument - this means
-		you are not getting any overflow checking in this case.
-
 - Boot Delay:	CONFIG_BOOTDELAY - in seconds
 		Delay before automatically booting the default image;
 		set to -1 to disable autoboot.

configs/bayleybay_defconfig

@@ -37,4 +37,3 @@ CONFIG_VIDEO_VESA=y
 CONFIG_FRAMEBUFFER_SET_VESA_MODE=y
 CONFIG_FRAMEBUFFER_VESA_MODE_11A=y
 CONFIG_USE_PRIVATE_LIBGCC=y
-CONFIG_SYS_VSNPRINTF=y

configs/chromebook_link_defconfig

@@ -38,5 +38,4 @@ CONFIG_VIDEO_VESA=y
 CONFIG_FRAMEBUFFER_SET_VESA_MODE=y
 CONFIG_FRAMEBUFFER_VESA_MODE_11A=y
 CONFIG_USE_PRIVATE_LIBGCC=y
-CONFIG_SYS_VSNPRINTF=y
 CONFIG_TPM=y

configs/chromebox_panther_defconfig

@@ -33,5 +33,4 @@ CONFIG_VIDEO_VESA=y
 CONFIG_FRAMEBUFFER_SET_VESA_MODE=y
 CONFIG_FRAMEBUFFER_VESA_MODE_11A=y
 CONFIG_USE_PRIVATE_LIBGCC=y
-CONFIG_SYS_VSNPRINTF=y
 CONFIG_TPM=y

configs/coreboot-x86_defconfig

@@ -25,5 +25,4 @@ CONFIG_TPM_TIS_LPC=y
 CONFIG_USB=y
 CONFIG_DM_USB=y
 CONFIG_USE_PRIVATE_LIBGCC=y
-CONFIG_SYS_VSNPRINTF=y
 CONFIG_TPM=y

configs/crownbay_defconfig

@@ -36,4 +36,3 @@ CONFIG_DM_USB=y
 CONFIG_VIDEO_VESA=y
 CONFIG_FRAMEBUFFER_SET_VESA_MODE=y
 CONFIG_USE_PRIVATE_LIBGCC=y
-CONFIG_SYS_VSNPRINTF=y

configs/galileo_defconfig

@@ -28,4 +28,3 @@ CONFIG_TIMER=y
 CONFIG_USB=y
 CONFIG_DM_USB=y
 CONFIG_USE_PRIVATE_LIBGCC=y
-CONFIG_SYS_VSNPRINTF=y

configs/minnowmax_defconfig

@@ -39,4 +39,3 @@ CONFIG_VIDEO_VESA=y
 CONFIG_FRAMEBUFFER_SET_VESA_MODE=y
 CONFIG_FRAMEBUFFER_VESA_MODE_11A=y
 CONFIG_USE_PRIVATE_LIBGCC=y
-CONFIG_SYS_VSNPRINTF=y

configs/qemu-x86_defconfig

@@ -30,4 +30,3 @@ CONFIG_VIDEO_VESA=y
 CONFIG_FRAMEBUFFER_SET_VESA_MODE=y
 CONFIG_FRAMEBUFFER_VESA_MODE_111=y
 CONFIG_USE_PRIVATE_LIBGCC=y
-CONFIG_SYS_VSNPRINTF=y

configs/sandbox_defconfig

@@ -76,7 +76,6 @@ CONFIG_USB_EMUL=y
 CONFIG_USB_STORAGE=y
 CONFIG_USB_KEYBOARD=y
 CONFIG_SYS_USB_EVENT_POLL=y
-CONFIG_SYS_VSNPRINTF=y
 CONFIG_CMD_DHRYSTONE=y
 CONFIG_TPM=y
 CONFIG_LZ4=y

include/vsprintf.h

@@ -124,7 +124,6 @@ int sprintf(char *buf, const char *fmt, ...)
 int vsprintf(char *buf, const char *fmt, va_list args);
 char *simple_itoa(ulong i);
 
-#ifdef CONFIG_SYS_VSNPRINTF
 /**
  * Format a string and place it in a buffer
  *
@@ -199,17 +198,6 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
  * See the vsprintf() documentation for format string extensions over C99.
  */
 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
-#else
-/*
- * Use macros to silently drop the size parameter. Note that the 'cn'
- * versions are the same as the 'n' versions since the functions assume
- * there is always enough buffer space when !CONFIG_SYS_VSNPRINTF
- */
-#define snprintf(buf, size, fmt, args...) sprintf(buf, fmt, ##args)
-#define scnprintf(buf, size, fmt, args...) sprintf(buf, fmt, ##args)
-#define vsnprintf(buf, size, fmt, args...) vsprintf(buf, fmt, ##args)
-#define vscnprintf(buf, size, fmt, args...) vsprintf(buf, fmt, ##args)
-#endif /* CONFIG_SYS_VSNPRINTF */
 
 /**
  * print_grouped_ull() - print a value with digits grouped by ','

lib/Kconfig

@@ -27,15 +27,6 @@ config SYS_HZ
 	  get_timer() must operate in milliseconds and this option must be
 	  set to 1000.
 
-config SYS_VSNPRINTF
-	bool "Enable safe version of sprintf()"
-	help
-	  Since sprintf() can overflow its buffer, it is common to use
-	  snprintf() instead, which knows the buffer size and can avoid
-	  overflow. However, this does increase code size slightly (for
-	  Thumb-2, about 420 bytes). Enable this option for safety when
-	  using sprintf() with data you do not control.
-
 config USE_TINY_PRINTF
 	bool "Enable tiny printf() version"
 	help

lib/vsprintf.c

@@ -141,7 +141,6 @@ static noinline char *put_dec(char *buf, uint64_t num)
 #define SMALL	32		/* Must be 32 == 0x20 */
 #define SPECIAL	64		/* 0x */
 
-#ifdef CONFIG_SYS_VSNPRINTF
 /*
  * Macro to add a new character to our output string, but only if it will
  * fit. The macro moves to the next character position in the output string.
@@ -151,9 +150,6 @@ static noinline char *put_dec(char *buf, uint64_t num)
 		*(str) = (ch); \
 	++str; \
 	} while (0)
-#else
-#define ADDCH(str, ch)	(*(str)++ = (ch))
-#endif
 
 static char *number(char *buf, char *end, u64 num,
 		int base, int size, int precision, int type)
@@ -441,13 +437,11 @@ static int vsnprintf_internal(char *buf, size_t size, const char *fmt,
 				/* 't' added for ptrdiff_t */
 	char *end = buf + size;
 
-#ifdef CONFIG_SYS_VSNPRINTF
 	/* Make sure end is always >= buf - do we want this in U-Boot? */
 	if (end < buf) {
 		end = ((void *)-1);
 		size = end - buf;
 	}
-#endif
 	str = buf;
 
 	for (; *fmt ; ++fmt) {
@@ -609,21 +603,16 @@ repeat:
 			     flags);
 	}
 
-#ifdef CONFIG_SYS_VSNPRINTF
 	if (size > 0) {
 		ADDCH(str, '\0');
 		if (str > end)
 			end[-1] = '\0';
 		--str;
 	}
-#else
-	*str = '\0';
-#endif
 	/* the trailing null byte doesn't count towards the total */
 	return str - buf;
 }
 
-#ifdef CONFIG_SYS_VSNPRINTF
 int vsnprintf(char *buf, size_t size, const char *fmt,
 			      va_list args)
 {
@@ -666,7 +655,6 @@ int scnprintf(char *buf, size_t size, const char *fmt, ...)
 
 	return i;
 }
-#endif /* CONFIG_SYS_VSNPRINT */
 
 /**
  * Format a string and place it in a buffer (va_list version)