nvmem: mxs-ocotp: fix buffer overflow in read

commit d1306eb675ad7a9a760b6b8e8e189824b8db89e7 upstream.

This patch fixes the issue where the mxs_ocotp_read is reading
the ocotp in reg_size steps but decrements the remaining size
by 1. The number of iterations is thus four times higher,
overwriting the area behind the output buffer.

Fixes: c01e9a11ab6f ("nvmem: add driver for ocotp in i.MX23 and i.MX28")
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Stanislav Meduna <stano@meduna.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/mxs-ocotp.c b/drivers/nvmem/mxs-ocotp.c
index 8ba19bba31569f22c6529a739fa1d30adf5c2f0f..2bb3c5799ac4b0146b2760d8823fb1eb28a6bdaa 100644 (file)
--- a/drivers/nvmem/mxs-ocotp.c
+++ b/drivers/nvmem/mxs-ocotp.c
@@ -94,7 +94,7 @@ static int mxs_ocotp_read(void *context, const void *reg, size_t reg_size,
        if (ret)
                goto close_banks;
 
-       while (val_size) {
+       while (val_size >= reg_size) {
                if ((offset < OCOTP_DATA_OFFSET) || (offset % 16)) {
                        /* fill up non-data register */
                        *buf = 0;
@@ -103,7 +103,7 @@ static int mxs_ocotp_read(void *context, const void *reg, size_t reg_size,
                }
 
                buf++;
-               val_size--;
+               val_size -= reg_size;
                offset += reg_size;
        }