[PATCH] spi: spidev_test: Fix buffer overflow in unescape()

[Geert Uytterhoeven]

Sometimes spidev_test crashes with:

    *** Error in `spidev_test': munmap_chunk(): invalid pointer: 0x00022020 ***
    Aborted

or just

    Segmentation fault

This is due to transfer_escaped_string() miscalculating the required
size of the buffer by one byte, causing a buffer overflow in unescape().

Drop the bogus "+ 1" in the strlen() parameter to fix this.

Note that unescape() never copies the zero-terminator of the source
string, so it writes at most as many bytes as the length of the source
string.

Fixes: 30061915be6e3a2c (spi: spidev_test: Added input buffer from the terminal)
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.5+
---
 tools/spi/spidev_test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/spi/spidev_test.c b/tools/spi/spidev_test.c
index 8a73d8185316..f3825b676e38 100644
--- a/tools/spi/spidev_test.c
+++ b/tools/spi/spidev_test.c
@@ -284,7 +284,7 @@ static void parse_opts(int argc, char *argv[])
 
 static void transfer_escaped_string(int fd, char *str)
 {
-	size_t size = strlen(str + 1);
+	size_t size = strlen(str);
 	uint8_t *tx;
 	uint8_t *rx;
 
-- 
2.8.1