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| author | Justin Stitt <justinstitt@google.com> | 2023-09-22 11:49:14 +0000 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2023-10-02 11:07:02 -0700 |
| commit | cba58fcbc4ab75d8814ec43db32d4830670526f8 (patch) | |
| tree | 901586c46e78e3381a477de341ea41e92a17cdc2 /drivers/isdn | |
| parent | 5c80c4fced22ae719d37db754144e75688eb52c8 (diff) | |
| download | lwn-cba58fcbc4ab75d8814ec43db32d4830670526f8.tar.gz lwn-cba58fcbc4ab75d8814ec43db32d4830670526f8.zip | |
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>
Diffstat (limited to 'drivers/isdn')
| -rw-r--r-- | drivers/isdn/capi/kcapi.c | 4 |
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; |