Messages in this thread Patch in this message | | | From | Rasmus Villemoes <> | Subject | [PATCH 1/7] net: core: improve sanity checking in __dev_alloc_name | Date | Mon, 13 Nov 2017 00:15:04 +0100 |
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__dev_alloc_name is called from the public (and exported) dev_alloc_name(), so we don't have a guarantee that strlen(name) is at most IFNAMSIZ. If somebody manages to get __dev_alloc_name called with a % char beyond the 31st character, we'd be making a snprintf() call that will very easily crash the kernel (using an appropriate %p extension, we'll likely dereference some completely bogus pointer).
In the normal case where strlen() is sane, we don't even save anything by limiting to IFNAMSIZ, so just use strchr().
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/dev.c b/net/core/dev.c index 11596a302a26..87e19804757b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1062,7 +1062,7 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) unsigned long *inuse; struct net_device *d; - p = strnchr(name, IFNAMSIZ-1, '%'); + p = strchr(name, '%'); if (p) { /* * Verify the string as this thing may have come from -- 2.11.0
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