[PATCH AUTOSEL 4.14 074/127] tools: gpio-hammer: Avoid potential overflow in main

Sasha Levin
2020-09-18T02:33:24Z

From: Gabriel Ravier <gabravier@gmail.com>

[ Upstream commit d1ee7e1f5c9191afb69ce46cc7752e4257340a31 ]

If '-o' was used more than 64 times in a single invocation of gpio-hammer,
this could lead to an overflow of the 'lines' array. This commit fixes
this by avoiding the overflow and giving a proper diagnostic back to the
user

Signed-off-by: Gabriel Ravier <gabravier@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/gpio/gpio-hammer.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/gpio/gpio-hammer.c b/tools/gpio/gpio-hammer.c
index 4bcb234c0fcab..3da5462a0c7d3 100644
--- a/tools/gpio/gpio-hammer.c
+++ b/tools/gpio/gpio-hammer.c
@@ -138,7 +138,14 @@ int main(int argc, char **argv)
device_name = optarg;
break;
case 'o':
- lines[i] = strtoul(optarg, NULL, 10);
+ /*
+ * Avoid overflow. Do not immediately error, we want to
+ * be able to accurately report on the amount of times
+ * '-o' was given to give an accurate error message
+ */
+ if (i < GPIOHANDLES_MAX)
+ lines[i] = strtoul(optarg, NULL, 10);
+
i++;
break;
case '?':
@@ -146,6 +153,14 @@ int main(int argc, char **argv)
return -1;
}
}
+
+ if (i >= GPIOHANDLES_MAX) {
+ fprintf(stderr,
+ "Only %d occurences of '-o' are allowed, %d were found\n",
+ GPIOHANDLES_MAX, i + 1);
+ return -1;
+ }
+
nlines = i;

if (!device_name || !nlines) {
--
2.25.1