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authorJustin Stitt <justinstitt@google.com>2023-09-22 11:49:14 +0000
committerKees Cook <keescook@chromium.org>2023-10-02 11:07:02 -0700
commitcba58fcbc4ab75d8814ec43db32d4830670526f8 (patch)
tree901586c46e78e3381a477de341ea41e92a17cdc2
parent5c80c4fced22ae719d37db754144e75688eb52c8 (diff)
isdn: kcapi: replace deprecated strncpy with strscpy_pad
`strncpy` is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. `buf` is used in this context as a data buffer with 64 bytes of memory to be occupied by capi_manufakturer. We see the caller capi20_get_manufacturer() passes data.manufacturer as its `buf` argument which is then later passed over to user space. Due to this, let's keep the NUL-padding that strncpy provided by using strscpy_pad so as to not leak any stack data. | cdev->errcode = capi20_get_manufacturer(data.contr, data.manufacturer); | if (cdev->errcode) | return -EIO; | | if (copy_to_user(argp, data.manufacturer, | sizeof(data.manufacturer))) | return -EFAULT; Perhaps this would also be a good instance to use `strtomem_pad` for but in my testing the compiler was not able to determine the size of `buf` -- even with all the hints. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20230922-strncpy-drivers-isdn-capi-kcapi-c-v1-1-55fcf8b075fb@google.com Signed-off-by: Kees Cook <keescook@chromium.org>
-rw-r--r--drivers/isdn/capi/kcapi.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/isdn/capi/kcapi.c b/drivers/isdn/capi/kcapi.c
index ae24848af233..136ba9fe55e0 100644
--- a/drivers/isdn/capi/kcapi.c
+++ b/drivers/isdn/capi/kcapi.c
@@ -732,7 +732,7 @@ u16 capi20_get_manufacturer(u32 contr, u8 buf[CAPI_MANUFACTURER_LEN])
u16 ret;
if (contr == 0) {
- strncpy(buf, capi_manufakturer, CAPI_MANUFACTURER_LEN);
+ strscpy_pad(buf, capi_manufakturer, CAPI_MANUFACTURER_LEN);
return CAPI_NOERROR;
}
@@ -740,7 +740,7 @@ u16 capi20_get_manufacturer(u32 contr, u8 buf[CAPI_MANUFACTURER_LEN])
ctr = get_capi_ctr_by_nr(contr);
if (ctr && ctr->state == CAPI_CTR_RUNNING) {
- strncpy(buf, ctr->manu, CAPI_MANUFACTURER_LEN);
+ strscpy_pad(buf, ctr->manu, CAPI_MANUFACTURER_LEN);
ret = CAPI_NOERROR;
} else
ret = CAPI_REGNOTINSTALLED;