[RFC][PATCH 2/5] lib: add error checking to hex2bin

From: Mimi Zohar
Date: Fri Sep 16 2011 - 08:51:10 EST


hex2bin converts a hexadecimal string to its binary representation.
The original version of hex2bin did not do any error checking. This
patch adds error checking and returns the result.

Changelog:
- use the new unpack_hex_byte()
- add __must_check compiler option (Andy Shevchenko's suggestion)
- change function API to return error checking result
(based on Tetsuo Handa's initial patch)

Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
---
include/linux/kernel.h | 2 +-
lib/hexdump.c | 11 +++++++----
2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index d8ea13b..3021e64 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -382,7 +382,7 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
}

extern int hex_to_bin(char ch);
-extern void hex2bin(u8 *dst, const char *src, size_t count);
+extern bool __must_check hex2bin(u8 *dst, const char *src, size_t count);

/*
* unpack_hex_byte - convert 2 asii hex digits into a byte
diff --git a/lib/hexdump.c b/lib/hexdump.c
index f5fe6ba..7711095 100644
--- a/lib/hexdump.c
+++ b/lib/hexdump.c
@@ -38,14 +38,17 @@ EXPORT_SYMBOL(hex_to_bin);
* @dst: binary result
* @src: ascii hexadecimal string
* @count: result length
+ *
+ * Returns true on success, false in case of bad input.
*/
-void hex2bin(u8 *dst, const char *src, size_t count)
+bool hex2bin(u8 *dst, const char *src, size_t count)
{
while (count--) {
- *dst = hex_to_bin(*src++) << 4;
- *dst += hex_to_bin(*src++);
- dst++;
+ if (!unpack_hex_byte(dst++, src))
+ return false;
+ src += 2;
}
+ return true;
}
EXPORT_SYMBOL(hex2bin);

--
1.7.3.4

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