diff options
| author | Lee Jones <lee@kernel.org> | 2023-12-13 16:42:30 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-15 13:55:29 +0100 |
| commit | 0466e7e693efe6647f23532529a9c41a1fa5f4ac (patch) | |
| tree | 36a638b48af6e7be268add285008b5830c9bec51 | |
| parent | b8fb6db6cb04e3c35d661d0f6cf6f8dc7444ce0c (diff) | |
usb: gadget: configfs: Replace snprintf() with the safer scnprintf() variant
There is a general misunderstanding amongst engineers that {v}snprintf()
returns the length of the data *actually* encoded into the destination
array. However, as per the C99 standard {v}snprintf() really returns
the length of the data that *would have been* written if there were
enough space for it. This misunderstanding has led to buffer-overruns
in the past. It's generally considered safer to use the {v}scnprintf()
variants in their place (or even sprintf() in simple cases). So let's
do that.
Link: https://lwn.net/Articles/69419/
Link: https://github.com/KSPP/linux/issues/105
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20231213164246.1021885-2-lee@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/gadget/configfs.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c index b7d2a1313a68..ce3cfa1f36f5 100644 --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c @@ -606,10 +606,11 @@ static struct config_group *function_make( char *instance_name; int ret; - ret = snprintf(buf, MAX_NAME_LEN, "%s", name); - if (ret >= MAX_NAME_LEN) + if (strlen(name) >= MAX_NAME_LEN) return ERR_PTR(-ENAMETOOLONG); + scnprintf(buf, MAX_NAME_LEN, "%s", name); + func_name = buf; instance_name = strchr(func_name, '.'); if (!instance_name) { @@ -701,10 +702,12 @@ static struct config_group *config_desc_make( int ret; gi = container_of(group, struct gadget_info, configs_group); - ret = snprintf(buf, MAX_NAME_LEN, "%s", name); - if (ret >= MAX_NAME_LEN) + + if (strlen(name) >= MAX_NAME_LEN) return ERR_PTR(-ENAMETOOLONG); + scnprintf(buf, MAX_NAME_LEN, "%s", name); + num_str = strchr(buf, '.'); if (!num_str) { pr_err("Unable to locate . in name.bConfigurationValue\n"); |