linux-hardening - [net-next V2 06/13] net/mlx5: simplify mlx5_set_driver

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Date: Wed, 15 Nov 2023 11:36:42 -0800
From: Saeed Mahameed <saeed@...nel.org>
To: "David S. Miller" <davem@...emloft.net>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Eric Dumazet <edumazet@...gle.com>
Cc: Saeed Mahameed <saeedm@...dia.com>,
	netdev@...r.kernel.org,
	Tariq Toukan <tariqt@...dia.com>,
	Justin Stitt <justinstitt@...gle.com>,
	linux-hardening@...r.kernel.org,
	Kees Cook <keescook@...omium.org>
Subject: [net-next V2 06/13] net/mlx5: simplify mlx5_set_driver_version string assignments

From: Justin Stitt <justinstitt@...gle.com>

In total, just assigning this version string takes:
(1) strncpy()'s
(5) strlen()'s
(3) strncat()'s
(1) snprintf()'s
(4) max_t()'s

Moreover, `strncpy` is deprecated [1] and `strncat` really shouldn't be
used either [2]. With this in mind, let's simply use a single
`snprintf`.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://elixir.bootlin.com/linux/v6.6-rc5/source/include/linux/fortify-string.h#L448 [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@...r.kernel.org
Cc: Kees Cook <keescook@...omium.org>
Signed-off-by: Justin Stitt <justinstitt@...gle.com>
Reviewed-by: Kees Cook <keescook@...omium.org>
Signed-off-by: Saeed Mahameed <saeedm@...dia.com>
---
 .../net/ethernet/mellanox/mlx5/core/main.c    | 20 +++----------------
 1 file changed, 3 insertions(+), 17 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index a17152c1cbb2..bccf6e53556c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -219,7 +219,6 @@ static void mlx5_set_driver_version(struct mlx5_core_dev *dev)
 	int driver_ver_sz = MLX5_FLD_SZ_BYTES(set_driver_version_in,
 					      driver_version);
 	u8 in[MLX5_ST_SZ_BYTES(set_driver_version_in)] = {};
-	int remaining_size = driver_ver_sz;
 	char *string;
 
 	if (!MLX5_CAP_GEN(dev, driver_version))
@@ -227,22 +226,9 @@ static void mlx5_set_driver_version(struct mlx5_core_dev *dev)
 
 	string = MLX5_ADDR_OF(set_driver_version_in, in, driver_version);
 
-	strncpy(string, "Linux", remaining_size);
-
-	remaining_size = max_t(int, 0, driver_ver_sz - strlen(string));
-	strncat(string, ",", remaining_size);
-
-	remaining_size = max_t(int, 0, driver_ver_sz - strlen(string));
-	strncat(string, KBUILD_MODNAME, remaining_size);
-
-	remaining_size = max_t(int, 0, driver_ver_sz - strlen(string));
-	strncat(string, ",", remaining_size);
-
-	remaining_size = max_t(int, 0, driver_ver_sz - strlen(string));
-
-	snprintf(string + strlen(string), remaining_size, "%u.%u.%u",
-		LINUX_VERSION_MAJOR, LINUX_VERSION_PATCHLEVEL,
-		LINUX_VERSION_SUBLEVEL);
+	snprintf(string, driver_ver_sz, "Linux,%s,%u.%u.%u",
+		 KBUILD_MODNAME, LINUX_VERSION_MAJOR,
+		 LINUX_VERSION_PATCHLEVEL, LINUX_VERSION_SUBLEVEL);
 
 	/*Send the command*/
 	MLX5_SET(set_driver_version_in, in, opcode,
-- 
2.41.0