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authorJustin Stitt <justinstitt@google.com>2023-10-20 19:39:02 +0000
committerSebastian Reichel <sebastian.reichel@collabora.com>2023-10-21 00:33:02 +0200
commit81f07d2b0c4db3b6e53d90419db915c75beb6326 (patch)
tree6afa870c361f58199a32b4e500765ac7fbfa6d19
parente1402bd297a3477c16eca4c1e4094372237f40a7 (diff)
downloadlwn-81f07d2b0c4db3b6e53d90419db915c75beb6326.tar.gz
lwn-81f07d2b0c4db3b6e53d90419db915c75beb6326.zip
power: supply: surface_battery: replace deprecated strncpy with strscpy
strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. We expect bat->name to be NUL-terminated based on its usage with strcmp(): power_supply_core.c: 445: return strcmp(psy->desc->name, name) == 0; ... and also by the manual `... - 1` for the length argument of the original strncpy() invocation. Furthermore, no NUL-padding is needed as bat is zero-allocated before calling spwr_battery_init(): 826: bat = devm_kzalloc(&sdev->dev, sizeof(*bat), GFP_KERNEL); 827: if (!bat) 828: return -ENOMEM; 829: 830: spwr_battery_init(bat, sdev, p->registry, p->name); ... this means any further NUL-byte assignments (like the ones that strncpy() does) are redundant. Considering the above, a suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. Let's also opt to use the more idiomatic strscpy() usage of: (dest, src, sizeof(dest)). Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> Link: https://lore.kernel.org/r/20231020-strncpy-drivers-power-supply-surface_battery-c-v2-1-29ed16b2caf1@google.com Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
-rw-r--r--drivers/power/supply/surface_battery.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/power/supply/surface_battery.c b/drivers/power/supply/surface_battery.c
index 19d2f8834e56..196d290dc596 100644
--- a/drivers/power/supply/surface_battery.c
+++ b/drivers/power/supply/surface_battery.c
@@ -722,7 +722,7 @@ static void spwr_battery_init(struct spwr_battery_device *bat, struct ssam_devic
struct ssam_event_registry registry, const char *name)
{
mutex_init(&bat->lock);
- strncpy(bat->name, name, ARRAY_SIZE(bat->name) - 1);
+ strscpy(bat->name, name, sizeof(bat->name));
bat->sdev = sdev;