| Message ID | 20210710164615.GA690067@pc (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dax: replace sprintf() by scnprintf() | expand |
On Sat, 2021-07-10 at 17:46 +0100, Salah Triki wrote: > Replace sprintf() by scnprintf() in order to avoid buffer overflows. OK but also not strictly necessary. DAX_NAME_LEN is 30. Are you finding and changing these manually or with a script? > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c [] > @@ -76,7 +76,7 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf, > fields = sscanf(buf, "dax%d.%d", ®ion_id, &id); > if (fields != 2) > return -EINVAL; > - sprintf(devname, "dax%d.%d", region_id, id); > + scnprintf(devname, DAX_NAME_LEN, "dax%d.%d", region_id, id); > if (!sysfs_streq(buf, devname)) > return -EINVAL; > >
On Sat, Jul 10, 2021 at 10:04:48AM -0700, Joe Perches wrote: > On Sat, 2021-07-10 at 17:46 +0100, Salah Triki wrote: > > Replace sprintf() by scnprintf() in order to avoid buffer overflows. > > OK but also not strictly necessary. DAX_NAME_LEN is 30. > > Are you finding and changing these manually or with a script? > > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > [] > > @@ -76,7 +76,7 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf, > > fields = sscanf(buf, "dax%d.%d", ®ion_id, &id); > > if (fields != 2) > > return -EINVAL; > > - sprintf(devname, "dax%d.%d", region_id, id); > > + scnprintf(devname, DAX_NAME_LEN, "dax%d.%d", region_id, id); > > if (!sysfs_streq(buf, devname)) > > return -EINVAL; > > > > > > since region_id and id are unsigned long may be devname should be char[21]. I'm finding and changing these manually. Thanx
On Mon, 2021-07-12 at 13:26 +0100, Salah Triki wrote: > On Sat, Jul 10, 2021 at 10:04:48AM -0700, Joe Perches wrote: > > On Sat, 2021-07-10 at 17:46 +0100, Salah Triki wrote: > > > Replace sprintf() by scnprintf() in order to avoid buffer overflows. > > > > OK but also not strictly necessary. DAX_NAME_LEN is 30. > > > > Are you finding and changing these manually or with a script? > > > > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > > [] > > > @@ -76,7 +76,7 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf, > > > fields = sscanf(buf, "dax%d.%d", ®ion_id, &id); > > > if (fields != 2) > > > return -EINVAL; > > > - sprintf(devname, "dax%d.%d", region_id, id); > > > + scnprintf(devname, DAX_NAME_LEN, "dax%d.%d", region_id, id); > > > if (!sysfs_streq(buf, devname)) > > > return -EINVAL; > > > > > > > > > > > > since region_id and id are unsigned long may be devname should be > char[21]. I think you need to look at the code a bit more carefully. unsigned int region_id, id; Also the output is %d, so the maximum length of each output int is 10 with a possible leading minus sign. 3 + 10 + 1 + 10 + 1. So 25 not 21 which is too small. The %d uses could be changed to %u to make it 23. But really it hardly matters as 30 is sufficent and the function call depth here isn't particularly high. > I'm finding and changing these manually. coccinelle could help. https://coccinelle.gitlabpages.inria.fr/website/
On Mon, Jul 12, 2021 at 09:14:53AM -0700, Joe Perches wrote: > On Mon, 2021-07-12 at 13:26 +0100, Salah Triki wrote: > > On Sat, Jul 10, 2021 at 10:04:48AM -0700, Joe Perches wrote: > > > On Sat, 2021-07-10 at 17:46 +0100, Salah Triki wrote: > > > > Replace sprintf() by scnprintf() in order to avoid buffer overflows. > > > > > > OK but also not strictly necessary. DAX_NAME_LEN is 30. > > > > > > Are you finding and changing these manually or with a script? > > > > > > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > > > [] > > > > @@ -76,7 +76,7 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf, > > > > fields = sscanf(buf, "dax%d.%d", ®ion_id, &id); > > > > if (fields != 2) > > > > return -EINVAL; > > > > - sprintf(devname, "dax%d.%d", region_id, id); > > > > + scnprintf(devname, DAX_NAME_LEN, "dax%d.%d", region_id, id); > > > > if (!sysfs_streq(buf, devname)) > > > > return -EINVAL; > > > > > > > > > > > > > > > > > > since region_id and id are unsigned long may be devname should be > > char[21]. > > I think you need to look at the code a bit more carefully. > > unsigned int region_id, id; > > Also the output is %d, so the maximum length of each output > int is 10 with a possible leading minus sign. > > 3 + 10 + 1 + 10 + 1. So 25 not 21 which is too small. > > The %d uses could be changed to %u to make it 23. > But really it hardly matters as 30 is sufficent and the > function call depth here isn't particularly high. > > > I'm finding and changing these manually. > > coccinelle could help. > https://coccinelle.gitlabpages.inria.fr/website/ > > Thanx
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 5aee26e1bbd6..bcae4be6ae76 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -76,7 +76,7 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf, fields = sscanf(buf, "dax%d.%d", ®ion_id, &id); if (fields != 2) return -EINVAL; - sprintf(devname, "dax%d.%d", region_id, id); + scnprintf(devname, DAX_NAME_LEN, "dax%d.%d", region_id, id); if (!sysfs_streq(buf, devname)) return -EINVAL;
Replace sprintf() by scnprintf() in order to avoid buffer overflows. Signed-off-by: Salah Triki <salah.triki@gmail.com> --- drivers/dax/bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)