crypto: lrw,xts - Replace strlcpy with strscpy

[ Upstream commit babb80b3ecc6f40c962e13c654ebcd27f25ee327 ]

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 of -errno
is used to check for truncation instead of sizeof(dest).

[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 <azeemshaikh38@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/crypto/lrw.c b/crypto/lrw.c
index 8d59a66..fb8892e 100644 (file)
--- a/crypto/lrw.c
+++ b/crypto/lrw.c
@@ -357,10 +357,10 @@ static int lrw_create(struct crypto_template *tmpl, struct rtattr **tb)
         * cipher name.
         */
        if (!strncmp(cipher_name, "ecb(", 4)) {
-               unsigned len;
+               int len;
 
-               len = strlcpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
-               if (len < 2 || len >= sizeof(ecb_name))
+               len = strscpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
+               if (len < 2)
                        goto err_free_inst;
 
                if (ecb_name[len - 1] != ')')

diff --git a/crypto/xts.c b/crypto/xts.c
index de6cbcf..b050206 100644 (file)
--- a/crypto/xts.c
+++ b/crypto/xts.c
@@ -396,10 +396,10 @@ static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
         * cipher name.
         */
        if (!strncmp(cipher_name, "ecb(", 4)) {
-               unsigned len;
+               int len;
 
-               len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
-               if (len < 2 || len >= sizeof(ctx->name))
+               len = strscpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
+               if (len < 2)
                        goto err_free_inst;
 
                if (ctx->name[len - 1] != ')')