`strncpy` is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.
We expect `irqname` to be NUL-terminated based on its use with
of_irq_get_byname() -> of_property_match_string() wherein it is used
with a format string and a `strcmp`:
| pr_debug("comparing %s with %s\n", string, p);
| if (strcmp(string, p) == 0)
| return i; /* Found it; return index */
NUL-padding is not required as is evident by other assignments to
`irqname` which do not NUL-pad:
| if (port->flags & MVPP2_F_DT_COMPAT)
| snprintf(irqname, sizeof(irqname), "tx-cpu%d", i);
| else
| snprintf(irqname, sizeof(irqname), "hif%d", i);
Considering the above, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer
without unnecessarily NUL-padding.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: [email protected]
Signed-off-by: Justin Stitt <[email protected]>
---
Note: build-tested only.
---
drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 21c3f9b015c8..331dba2ae13d 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -5831,7 +5831,7 @@ static int mvpp2_multi_queue_vectors_init(struct mvpp2_port *port,
v->type = MVPP2_QUEUE_VECTOR_SHARED;
if (port->flags & MVPP2_F_DT_COMPAT)
- strncpy(irqname, "rx-shared", sizeof(irqname));
+ strscpy(irqname, "rx-shared", sizeof(irqname));
}
if (port_node)
---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231010-strncpy-drivers-net-ethernet-marvell-mvpp2-mvpp2_main-c-e9743cf1cf8f
Best regards,
--
Justin Stitt <[email protected]>
On Tue, Oct 10, 2023 at 09:24:42PM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings
> [1] and as such we should prefer more robust and less ambiguous string
> interfaces.
>
> We expect `irqname` to be NUL-terminated based on its use with
> of_irq_get_byname() -> of_property_match_string() wherein it is used
> with a format string and a `strcmp`:
> | pr_debug("comparing %s with %s\n", string, p);
> | if (strcmp(string, p) == 0)
> | return i; /* Found it; return index */
>
> NUL-padding is not required as is evident by other assignments to
> `irqname` which do not NUL-pad:
> | if (port->flags & MVPP2_F_DT_COMPAT)
> | snprintf(irqname, sizeof(irqname), "tx-cpu%d", i);
> | else
> | snprintf(irqname, sizeof(irqname), "hif%d", i);
>
> Considering the above, a suitable replacement is `strscpy` [2] due to
> the fact that it guarantees NUL-termination on the destination buffer
> without unnecessarily NUL-padding.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
Yup, direct replacement.
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
Hello:
This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <[email protected]>:
On Tue, 10 Oct 2023 21:24:42 +0000 you wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings
> [1] and as such we should prefer more robust and less ambiguous string
> interfaces.
>
> We expect `irqname` to be NUL-terminated based on its use with
> of_irq_get_byname() -> of_property_match_string() wherein it is used
> with a format string and a `strcmp`:
> | pr_debug("comparing %s with %s\n", string, p);
> | if (strcmp(string, p) == 0)
> | return i; /* Found it; return index */
>
> [...]
Here is the summary with links:
- net: mvpp2: replace deprecated strncpy with strscpy
https://git.kernel.org/netdev/net-next/c/fda9e465a9d9
You are awesome, thank you!
--
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