xfrm: xfrm_user: use strscpy() for alg_name

[PATCH net-next] xfrm: xfrm_user: use strscpy() for alg_name

Posted by Miguel García 1 month, 2 weeks ago

Replace the strcpy() calls that copy the canonical algorithm name into
alg_name with strscpy() to avoid potential overflows and guarantee NULL
termination.

Destination is alg_name in xfrm_algo/xfrm_algo_auth/xfrm_algo_aead
(size CRYPTO_MAX_ALG_NAME).

Tested in QEMU (BusyBox/Alpine rootfs):
 - Added ESP AEAD (rfc4106(gcm(aes))) and classic ESP (sha256 + cbc(aes))
 - Verified canonical names via ip -d xfrm state
 - Checked IPComp negative (unknown algo) and deflate path

Signed-off-by: Miguel García <miguelgarciaroman8@gmail.com>
---
 net/xfrm/xfrm_user.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 59f258daf830..d65def556b6b 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -593,7 +593,7 @@ static int attach_one_algo(struct xfrm_algo **algpp, u8 *props,
 	if (!p)
 		return -ENOMEM;
 
-	strcpy(p->alg_name, algo->name);
+	strscpy(p->alg_name, algo->name);
 	*algpp = p;
 	return 0;
 }
@@ -620,7 +620,7 @@ static int attach_crypt(struct xfrm_state *x, struct nlattr *rta,
 	if (!p)
 		return -ENOMEM;
 
-	strcpy(p->alg_name, algo->name);
+	strscpy(p->alg_name, algo->name);
 	x->ealg = p;
 	x->geniv = algo->uinfo.encr.geniv;
 	return 0;
@@ -649,7 +649,7 @@ static int attach_auth(struct xfrm_algo_auth **algpp, u8 *props,
 	if (!p)
 		return -ENOMEM;
 
-	strcpy(p->alg_name, algo->name);
+	strscpy(p->alg_name, algo->name);
 	p->alg_key_len = ualg->alg_key_len;
 	p->alg_trunc_len = algo->uinfo.auth.icv_truncbits;
 	memcpy(p->alg_key, ualg->alg_key, (ualg->alg_key_len + 7) / 8);
@@ -684,7 +684,7 @@ static int attach_auth_trunc(struct xfrm_algo_auth **algpp, u8 *props,
 	if (!p)
 		return -ENOMEM;
 
-	strcpy(p->alg_name, algo->name);
+	strscpy(p->alg_name, algo->name);
 	if (!p->alg_trunc_len)
 		p->alg_trunc_len = algo->uinfo.auth.icv_truncbits;
 
@@ -714,7 +714,7 @@ static int attach_aead(struct xfrm_state *x, struct nlattr *rta,
 	if (!p)
 		return -ENOMEM;
 
-	strcpy(p->alg_name, algo->name);
+	strscpy(p->alg_name, algo->name);
 	x->aead = p;
 	x->geniv = algo->uinfo.aead.geniv;
 	return 0;
-- 
2.34.1

Re: [PATCH net-next] xfrm: xfrm_user: use strscpy() for alg_name

Posted by Steffen Klassert 1 month, 2 weeks ago

On Thu, Aug 14, 2025 at 09:32:17PM +0200, Miguel García wrote:
> Replace the strcpy() calls that copy the canonical algorithm name into
> alg_name with strscpy() to avoid potential overflows and guarantee NULL
> termination.
> 
> Destination is alg_name in xfrm_algo/xfrm_algo_auth/xfrm_algo_aead
> (size CRYPTO_MAX_ALG_NAME).
> 
> Tested in QEMU (BusyBox/Alpine rootfs):
>  - Added ESP AEAD (rfc4106(gcm(aes))) and classic ESP (sha256 + cbc(aes))
>  - Verified canonical names via ip -d xfrm state
>  - Checked IPComp negative (unknown algo) and deflate path
> 
> Signed-off-by: Miguel García <miguelgarciaroman8@gmail.com>

Patch applied, thanks!

Re: [PATCH net-next] xfrm: xfrm_user: use strscpy() for alg_name

Posted by Miguel García Román 1 month, 2 weeks ago

El dom, 17 ago 2025 a las 16:48, Steffen Klassert
(<steffen.klassert@secunet.com>) escribió:
>
> On Thu, Aug 14, 2025 at 09:32:17PM +0200, Miguel García wrote:
> > Replace the strcpy() calls that copy the canonical algorithm name into
> > alg_name with strscpy() to avoid potential overflows and guarantee NULL
> > termination.
> >
> > Destination is alg_name in xfrm_algo/xfrm_algo_auth/xfrm_algo_aead
> > (size CRYPTO_MAX_ALG_NAME).
> >
> > Tested in QEMU (BusyBox/Alpine rootfs):
> >  - Added ESP AEAD (rfc4106(gcm(aes))) and classic ESP (sha256 + cbc(aes))
> >  - Verified canonical names via ip -d xfrm state
> >  - Checked IPComp negative (unknown algo) and deflate path
> >
> > Signed-off-by: Miguel García <miguelgarciaroman8@gmail.com>
>
> Patch applied, thanks!
Perfect, thanks!