Dan,
What's your opinion on below alternative patch?
In addition to yours it makes would-overflow visible.
It does not check for output buffer having non-zero size but
as callers are local with #defined buffer size I don't think that would
be needed.
Author: Bruno Prémont <bonbons@xxxxxxxxxxxxxxxxx>
Date: Wed Sep 19 21:18:10 2012 +0200
Subject: HID: picoLCD: bounds check in dump_buff_as_hex()
Make sure we keep enough space for terminating NUL character after last
newline. If we have too much data, replace last byte with '.'s to
make overflow visible.
Using hex_dump_to_buffer() is not interesting as it adds more overhead
and does not append the trailing linefeed.
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Bruno Prémont <bonbons@xxxxxxxxxxxxxxxxx>
---
drivers/hid/hid-picolcd_debugfs.c | 14 ++++++++------
1 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/hid/hid-picolcd_debugfs.c b/drivers/hid/hid-picolcd_debugfs.c
index 868853a..c5c2fd9 100644
--- a/drivers/hid/hid-picolcd_debugfs.c
+++ b/drivers/hid/hid-picolcd_debugfs.c
@@ -381,16 +381,16 @@ static void dump_buff_as_hex(char *dst, size_t dst_sz, const u8 *data,
const size_t data_len)
{
int i, j;
- for (i = j = 0; i < data_len && j + 3 < dst_sz; i++) {
+ for (i = j = 0; i < data_len && j + 4 < dst_sz; i++) {
dst[j++] = hex_asc[(data[i] >> 4) & 0x0f];
dst[j++] = hex_asc[data[i] & 0x0f];
dst[j++] = ' ';
}
- if (j < dst_sz) {
- dst[j--] = '\0';
- dst[j] = '\n';
- } else
- dst[j] = '\0';
+ dst[j] = '\0';
+ if (j > 0)
+ dst[j-1] = '\n';
+ if (i < data_len && j > 2)
+ dst[j-2] = dst[j-3] = '.';
}
void picolcd_debug_out_report(struct picolcd_data *data,
--
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