From c00f3892f4f070f6f6b7e04b9e04a8b11b0e7157 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Wed, 27 Apr 2022 11:26:40 -0400 Subject: hex2bin: fix access beyond string end commit e4d8a29997731b3bb14059024b24df9f784288d0 upstream. If we pass too short string to "hex2bin" (and the string size without the terminating NUL character is even), "hex2bin" reads one byte after the terminating NUL character. This patch fixes it. Note that hex_to_bin returns -1 on error and hex2bin return -EINVAL on error - so we can't just return the variable "hi" or "lo" on error. This inconsistency may be fixed in the next merge window, but for the purpose of fixing this bug, we just preserve the existing behavior and return -1 and -EINVAL. Signed-off-by: Mikulas Patocka Reviewed-by: Andy Shevchenko Fixes: b78049831ffe ("lib: add error checking to hex2bin") Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- lib/hexdump.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/hexdump.c b/lib/hexdump.c index 0a21081acb09..c0a08ddcf94e 100644 --- a/lib/hexdump.c +++ b/lib/hexdump.c @@ -62,10 +62,13 @@ EXPORT_SYMBOL(hex_to_bin); int hex2bin(u8 *dst, const char *src, size_t count) { while (count--) { - int hi = hex_to_bin(*src++); - int lo = hex_to_bin(*src++); + int hi, lo; - if ((hi < 0) || (lo < 0)) + hi = hex_to_bin(*src++); + if (unlikely(hi < 0)) + return -EINVAL; + lo = hex_to_bin(*src++); + if (unlikely(lo < 0)) return -EINVAL; *dst++ = (hi << 4) | lo; -- cgit v1.2.3