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authorFlorian Westphal <fw@strlen.de>2024-01-19 13:34:32 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2024-01-24 20:02:30 +0100
commitb462579b2b86a8f5230543cadd3a4836be27baf7 (patch)
tree76e334ac0e22c3dea0a0c955a495ffda0d6c6bd7 /net
parentc9d9eb9c53d37cdebbad56b91e40baf42d5a97aa (diff)
netfilter: nf_tables: restrict anonymous set and map names to 16 bytes
nftables has two types of sets/maps, one where userspace defines the name, and anonymous sets/maps, where userspace defines a template name. For the latter, kernel requires presence of exactly one "%d". nftables uses "__set%d" and "__map%d" for this. The kernel will expand the format specifier and replaces it with the smallest unused number. As-is, userspace could define a template name that allows to move the set name past the 256 bytes upperlimit (post-expansion). I don't see how this could be a problem, but I would prefer if userspace cannot do this, so add a limit of 16 bytes for the '%d' template name. 16 bytes is the old total upper limit for set names that existed when nf_tables was merged initially. Fixes: 387454901bd6 ("netfilter: nf_tables: Allow set names of up to 255 chars") Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_tables_api.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 4b55533ce5ca..02f45424644b 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -24,6 +24,7 @@
#include <net/sock.h>
#define NFT_MODULE_AUTOLOAD_LIMIT (MODULE_NAME_LEN - sizeof("nft-expr-255-"))
+#define NFT_SET_MAX_ANONLEN 16
unsigned int nf_tables_net_id __read_mostly;
@@ -4413,6 +4414,9 @@ static int nf_tables_set_alloc_name(struct nft_ctx *ctx, struct nft_set *set,
if (p[1] != 'd' || strchr(p + 2, '%'))
return -EINVAL;
+ if (strnlen(name, NFT_SET_MAX_ANONLEN) >= NFT_SET_MAX_ANONLEN)
+ return -EINVAL;
+
inuse = (unsigned long *)get_zeroed_page(GFP_KERNEL);
if (inuse == NULL)
return -ENOMEM;