[PATCH] nvmem/mxs-ocotp: fix buffer overflow in read

Stanislav Meduna
2016-04-27T12:12:41Z

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")
---
drivers/nvmem/mxs-ocotp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvmem/mxs-ocotp.c b/drivers/nvmem/mxs-ocotp.c
index 8ba19bb..2bb3c57 100644
--- 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;
}

--
2.1.4