Re: [PATCH net-next v4] tipc: replace deprecated strcpy with strscpy in tipc_bearer_get_name()

[David Laight <david.laight.linux@gmail.com>]

On Wed,  2 Sep 2026 05:30:43 +0000
Ajith P V <ajithpv.linux@gmail.com> wrote:

> The `strcpy()` function is deprecated and moving towards code-tree
> elimination. Replacing it with `strscpy()` fixes potential buffer
> overflow vectors by ensuring safe NULL-termination based on the
> destination buffer size limit [1][2].
> 
> To make the interface safer and more robust for future callers, refactor
> `tipc_bearer_get_name()` to accept a destination buffer length parameter.
> Replace `strcpy()` with `strscpy()` and pass through any potential
> `-E2BIG` truncation error code up to the caller. Update the existing
> caller in `net/tipc/monitor.c` to pass its array size.

For real safety embed the char[TIPC_MAX_BEARER_NAME] in a struct and
pass the struct through.
Then you can use sizeof() in the function itself.

	David

> 
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy [1]
> Link: https://github.com/KSPP/linux/issues/88 [2]
> 
> Signed-off-by: Ajith P V <ajithpv.linux@gmail.com>
> ---
> v4:
>   - Avoid hard-coding TIPC_MAX_BEARER_NAME in the function body.
>   - Pass size_t len from the caller down to strscpy().
>   - Forward strscpy()'s -E2BIG error up through the existing int return type.
>   - Updated function documentation comment block.
> v3:
>   - Fix patch title as suggested by Tung Quang Nguyen.
>   - No code changes from v2.
> v2:
>   - Target net-next tree instead of standard net tree as requested by Tung Quang Nguyen.
>   - No code changes from v1.
> 
>  net/tipc/bearer.c  | 8 ++++++--
>  net/tipc/bearer.h  | 2 +-
>  net/tipc/monitor.c | 2 +-
>  3 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
> index 05dcd2f9e887..abd90e6bde09 100644
> --- a/net/tipc/bearer.c
> +++ b/net/tipc/bearer.c
> @@ -195,12 +195,14 @@ struct tipc_bearer *tipc_bearer_find(struct net *net, const char *name)
>  /*     tipc_bearer_get_name - get the bearer name from its id.
>   *     @net: network namespace
>   *     @name: a pointer to the buffer where the name will be stored.
> + *     @len: size of the destination buffer
>   *     @bearer_id: the id to get the name from.
>   */
> -int tipc_bearer_get_name(struct net *net, char *name, u32 bearer_id)
> +int tipc_bearer_get_name(struct net *net, char *name, size_t len, u32 bearer_id)
>  {
>  	struct tipc_net *tn = tipc_net(net);
>  	struct tipc_bearer *b;
> +	int ret;
>  
>  	if (bearer_id >= MAX_BEARERS)
>  		return -EINVAL;
> @@ -209,7 +211,9 @@ int tipc_bearer_get_name(struct net *net, char *name, u32 bearer_id)
>  	if (!b)
>  		return -EINVAL;
>  
> -	strcpy(name, b->name);
> +	ret = strscpy(name, b->name, len);
> +	if (ret < 0)
> +		return ret; /* Returns -E2BIG if destination buffer is too small */
>  	return 0;
>  }
>  
> diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
> index 41eac1ee0c09..12a322642de1 100644
> --- a/net/tipc/bearer.h
> +++ b/net/tipc/bearer.h
> @@ -226,7 +226,7 @@ int tipc_l2_send_msg(struct net *net, struct sk_buff *buf,
>  void tipc_bearer_add_dest(struct net *net, u32 bearer_id, u32 dest);
>  void tipc_bearer_remove_dest(struct net *net, u32 bearer_id, u32 dest);
>  struct tipc_bearer *tipc_bearer_find(struct net *net, const char *name);
> -int tipc_bearer_get_name(struct net *net, char *name, u32 bearer_id);
> +int tipc_bearer_get_name(struct net *net, char *name, size_t len, u32 bearer_id);
>  struct tipc_media *tipc_media_find(const char *name);
>  int tipc_bearer_setup(void);
>  void tipc_bearer_cleanup(void);
> diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
> index a94b9b36a700..8af49000a07c 100644
> --- a/net/tipc/monitor.c
> +++ b/net/tipc/monitor.c
> @@ -833,7 +833,7 @@ int __tipc_nl_add_monitor(struct net *net, struct tipc_nl_msg *msg,
>  	void *hdr;
>  	int ret;
>  
> -	ret = tipc_bearer_get_name(net, bearer_name, bearer_id);
> +	ret = tipc_bearer_get_name(net, bearer_name, sizeof(bearer_name), bearer_id);
>  	if (ret || !mon)
>  		return 0;
>