Prefer `strscpy` as it's a more robust interface.
There may have existed a bug here due to both `tbl->repl.name` and
`info->name` having a size of 32 as defined below:
| #define XT_TABLE_MAXNAMELEN 32
This may lead to buffer overreads in some situations -- `strscpy` solves
this by guaranteeing NUL-termination of the dest buffer.
Signed-off-by: Justin Stitt <[email protected]>
---
Note: build tested only
---
net/netfilter/xt_repldata.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/xt_repldata.h b/net/netfilter/xt_repldata.h
index 68ccbe50bb1e..63869fd0ec57 100644
--- a/net/netfilter/xt_repldata.h
+++ b/net/netfilter/xt_repldata.h
@@ -29,7 +29,7 @@
if (tbl == NULL) \
return NULL; \
term = (struct type##_error *)&(((char *)tbl)[term_offset]); \
- strncpy(tbl->repl.name, info->name, sizeof(tbl->repl.name)); \
+ strscpy(tbl->repl.name, info->name, sizeof(tbl->repl.name)); \
*term = (struct type##_error)typ2##_ERROR_INIT; \
tbl->repl.valid_hooks = hook_mask; \
tbl->repl.num_entries = nhooks + 1; \
--
2.41.0.640.ga95def55d0-goog
On Wednesday 2023-08-09 00:48, Justin Stitt wrote:
>Prefer `strscpy` as it's a more robust interface.
>
>There may have existed a bug here due to both `tbl->repl.name` and
>`info->name` having a size of 32 as defined below:
>| #define XT_TABLE_MAXNAMELEN 32
>
>This may lead to buffer overreads in some situations -- `strscpy` solves
>this by guaranteeing NUL-termination of the dest buffer.
It generally will not lead to overreads.
xt not only deals with strings on its own turf, it even takes
them from userspace-provided buffers, which means extra scrutiny is
absolutely required. Done in places like
x_tables.c: if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
(Which is not to say the strncpy->strscpy mop-up is bad.)