diff options
| author | Lee Jones <lee@kernel.org> | 2023-12-13 17:42:39 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-15 13:55:30 +0100 |
| commit | 9d4e3d15d7bf3439a6f3fb4aafc4f92ea2c5c5fd (patch) | |
| tree | 36dd7903bdd054f93385b28c5aa0b6d3e96f1eb5 | |
| parent | usb: mon_stat: Replace snprintf() with the safer scnprintf() variant (diff) | |
| download | linux-9d4e3d15d7bf3439a6f3fb4aafc4f92ea2c5c5fd.tar.xz linux-9d4e3d15d7bf3439a6f3fb4aafc4f92ea2c5c5fd.zip | |
usb: mon_text: 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/20231213164246.1021885-11-lee@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/mon/mon_text.c | 28 |
1 files changed, 5 insertions, 23 deletions
diff --git a/drivers/usb/mon/mon_text.c b/drivers/usb/mon/mon_text.c index 39cb14164652..2fe9b95bac1d 100644 --- a/drivers/usb/mon/mon_text.c +++ b/drivers/usb/mon/mon_text.c @@ -352,7 +352,7 @@ static int mon_text_open(struct inode *inode, struct file *file) rp->r.rnf_error = mon_text_error; rp->r.rnf_complete = mon_text_complete; - snprintf(rp->slab_name, SLAB_NAME_SZ, "mon_text_%p", rp); + scnprintf(rp->slab_name, SLAB_NAME_SZ, "mon_text_%p", rp); rp->e_slab = kmem_cache_create(rp->slab_name, sizeof(struct mon_event_text), sizeof(long), 0, mon_text_ctor); @@ -700,46 +700,28 @@ static const struct file_operations mon_fops_text_u = { int mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus) { - enum { NAMESZ = 10 }; + enum { NAMESZ = 12 }; char name[NAMESZ]; int busnum = ubus? ubus->busnum: 0; - int rc; if (mon_dir == NULL) return 0; if (ubus != NULL) { - rc = snprintf(name, NAMESZ, "%dt", busnum); - if (rc <= 0 || rc >= NAMESZ) - goto err_print_t; + scnprintf(name, NAMESZ, "%dt", busnum); mbus->dent_t = debugfs_create_file(name, 0600, mon_dir, mbus, &mon_fops_text_t); } - rc = snprintf(name, NAMESZ, "%du", busnum); - if (rc <= 0 || rc >= NAMESZ) - goto err_print_u; + scnprintf(name, NAMESZ, "%du", busnum); mbus->dent_u = debugfs_create_file(name, 0600, mon_dir, mbus, &mon_fops_text_u); - rc = snprintf(name, NAMESZ, "%ds", busnum); - if (rc <= 0 || rc >= NAMESZ) - goto err_print_s; + scnprintf(name, NAMESZ, "%ds", busnum); mbus->dent_s = debugfs_create_file(name, 0600, mon_dir, mbus, &mon_fops_stat); return 1; - -err_print_s: - debugfs_remove(mbus->dent_u); - mbus->dent_u = NULL; -err_print_u: - if (ubus != NULL) { - debugfs_remove(mbus->dent_t); - mbus->dent_t = NULL; - } -err_print_t: - return 0; } void mon_text_del(struct mon_bus *mbus) |