Messages in this thread | | | Date | Mon, 12 Jul 2021 17:48:50 +0100 | From | Salah Triki <> | Subject | Re: [PATCH] dax: replace sprintf() by scnprintf() |
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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
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