strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
Direct replacement is safe here since return value from all
callers of STRLCPY macro were ignored.
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89
Signed-off-by: Azeem Shaikh <[email protected]>
---
net/netfilter/ipset/ip_set_hash_netiface.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/net/netfilter/ipset/ip_set_hash_netiface.c b/net/netfilter/ipset/ip_set_hash_netiface.c
index 031073286236..95aeb31c60e0 100644
--- a/net/netfilter/ipset/ip_set_hash_netiface.c
+++ b/net/netfilter/ipset/ip_set_hash_netiface.c
@@ -40,7 +40,7 @@ MODULE_ALIAS("ip_set_hash:net,iface");
#define IP_SET_HASH_WITH_MULTI
#define IP_SET_HASH_WITH_NET0
-#define STRLCPY(a, b) strlcpy(a, b, IFNAMSIZ)
+#define STRSCPY(a, b) strscpy(a, b, IFNAMSIZ)
/* IPv4 variant */
@@ -182,11 +182,11 @@ hash_netiface4_kadt(struct ip_set *set, const struct sk_buff *skb,
if (!eiface)
return -EINVAL;
- STRLCPY(e.iface, eiface);
+ STRSCPY(e.iface, eiface);
e.physdev = 1;
#endif
} else {
- STRLCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
+ STRSCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
}
if (strlen(e.iface) == 0)
@@ -400,11 +400,11 @@ hash_netiface6_kadt(struct ip_set *set, const struct sk_buff *skb,
if (!eiface)
return -EINVAL;
- STRLCPY(e.iface, eiface);
+ STRSCPY(e.iface, eiface);
e.physdev = 1;
#endif
} else {
- STRLCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
+ STRSCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
}
if (strlen(e.iface) == 0)
--
2.41.0.162.gfafddb0af9-goog
On Tue, Jun 13, 2023 at 12:34:37AM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
>
> Direct replacement is safe here since return value from all
> callers of STRLCPY macro were ignored.
Yeah, the macro name is probably not super helpful here. It seems like
it should have originally be named IFNAME_CPY or something.
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
>
> Signed-off-by: Azeem Shaikh <[email protected]>
But, regardless:
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
On Tue, Jun 13, 2023 at 12:34:37AM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
>
> Direct replacement is safe here since return value from all
> callers of STRLCPY macro were ignored.
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
>
> Signed-off-by: Azeem Shaikh <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
On Tue, 13 Jun 2023, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
>
> Direct replacement is safe here since return value from all
> callers of STRLCPY macro were ignored.
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
>
> Signed-off-by: Azeem Shaikh <[email protected]>
Acked-by: Jozsef Kadlecsik <[email protected]>
Best regards,
Jozsef
> ---
> net/netfilter/ipset/ip_set_hash_netiface.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/net/netfilter/ipset/ip_set_hash_netiface.c b/net/netfilter/ipset/ip_set_hash_netiface.c
> index 031073286236..95aeb31c60e0 100644
> --- a/net/netfilter/ipset/ip_set_hash_netiface.c
> +++ b/net/netfilter/ipset/ip_set_hash_netiface.c
> @@ -40,7 +40,7 @@ MODULE_ALIAS("ip_set_hash:net,iface");
> #define IP_SET_HASH_WITH_MULTI
> #define IP_SET_HASH_WITH_NET0
>
> -#define STRLCPY(a, b) strlcpy(a, b, IFNAMSIZ)
> +#define STRSCPY(a, b) strscpy(a, b, IFNAMSIZ)
>
> /* IPv4 variant */
>
> @@ -182,11 +182,11 @@ hash_netiface4_kadt(struct ip_set *set, const struct sk_buff *skb,
>
> if (!eiface)
> return -EINVAL;
> - STRLCPY(e.iface, eiface);
> + STRSCPY(e.iface, eiface);
> e.physdev = 1;
> #endif
> } else {
> - STRLCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
> + STRSCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
> }
>
> if (strlen(e.iface) == 0)
> @@ -400,11 +400,11 @@ hash_netiface6_kadt(struct ip_set *set, const struct sk_buff *skb,
>
> if (!eiface)
> return -EINVAL;
> - STRLCPY(e.iface, eiface);
> + STRSCPY(e.iface, eiface);
> e.physdev = 1;
> #endif
> } else {
> - STRLCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
> + STRSCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
> }
>
> if (strlen(e.iface) == 0)
> --
> 2.41.0.162.gfafddb0af9-goog
>
>
>
-
E-mail : [email protected], [email protected]
PGP key : https://wigner.hu/~kadlec/pgp_public_key.txt
Address : Wigner Research Centre for Physics
H-1525 Budapest 114, POB. 49, Hungary
On Tue, 13 Jun 2023 00:34:37 +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
>
> [...]
Since this got Acked and it's a trivial change, I'll take this via the
hardening tree. Thanks!
Applied to for-next/hardening, thanks!
[1/1] netfilter: ipset: Replace strlcpy with strscpy
https://git.kernel.org/kees/c/0b2fa86361f4
--
Kees Cook