From: Bodo Stroesser <bostroesser@gmail.com>
To: Romain Perier <romain.perier@gmail.com>,
Kees Cook <keescook@chromium.org>,
kernel-hardening@lists.openwall.com,
"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 14/20] target: Manual replacement of the deprecated strlcpy() with return values
Date: Mon, 22 Feb 2021 17:00:30 +0100 [thread overview]
Message-ID: <c296eb89-32e2-0866-34f1-0bdd00d80f82@gmail.com> (raw)
In-Reply-To: <20210222151231.22572-15-romain.perier@gmail.com>
On 22.02.21 16:12, Romain Perier wrote:
> The strlcpy() reads the entire source buffer first, it is dangerous if
> the source buffer lenght is unbounded or possibility non NULL-terminated.
> It can lead to linear read overflows, crashes, etc...
>
> As recommended in the deprecated interfaces [1], it should be replaced
> by strscpy.
>
> This commit replaces all calls to strlcpy that handle the return values
> by the corresponding strscpy calls with new handling of the return
> values (as it is quite different between the two functions).
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
>
> Signed-off-by: Romain Perier <romain.perier@gmail.com>
> ---
> drivers/target/target_core_configfs.c | 33 +++++++++------------------------
> 1 file changed, 9 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
> index f04352285155..676215cd8847 100644
> --- a/drivers/target/target_core_configfs.c
> +++ b/drivers/target/target_core_configfs.c
> @@ -1325,16 +1325,11 @@ static ssize_t target_wwn_vendor_id_store(struct config_item *item,
> /* +2 to allow for a trailing (stripped) '\n' and null-terminator */
> unsigned char buf[INQUIRY_VENDOR_LEN + 2];
> char *stripped = NULL;
> - size_t len;
> + ssize_t len;
> ssize_t ret;
>
> - len = strlcpy(buf, page, sizeof(buf));
> - if (len < sizeof(buf)) {
> - /* Strip any newline added from userspace. */
> - stripped = strstrip(buf);
> - len = strlen(stripped);
> - }
> - if (len > INQUIRY_VENDOR_LEN) {
> + len = strscpy(buf, page, sizeof(buf));
> + if (len == -E2BIG) {
> pr_err("Emulated T10 Vendor Identification exceeds"
> " INQUIRY_VENDOR_LEN: " __stringify(INQUIRY_VENDOR_LEN)
> "\n");
> @@ -1381,16 +1376,11 @@ static ssize_t target_wwn_product_id_store(struct config_item *item,
> /* +2 to allow for a trailing (stripped) '\n' and null-terminator */
> unsigned char buf[INQUIRY_MODEL_LEN + 2];
> char *stripped = NULL;
> - size_t len;
> + ssize_t len;
> ssize_t ret;
>
> - len = strlcpy(buf, page, sizeof(buf));
> - if (len < sizeof(buf)) {
> - /* Strip any newline added from userspace. */
> - stripped = strstrip(buf);
> - len = strlen(stripped);
> - }
> - if (len > INQUIRY_MODEL_LEN) {
> + len = strscpy(buf, page, sizeof(buf));
> + if (len == -E2BIG) {
> pr_err("Emulated T10 Vendor exceeds INQUIRY_MODEL_LEN: "
> __stringify(INQUIRY_MODEL_LEN)
> "\n");
> @@ -1437,16 +1427,11 @@ static ssize_t target_wwn_revision_store(struct config_item *item,
> /* +2 to allow for a trailing (stripped) '\n' and null-terminator */
> unsigned char buf[INQUIRY_REVISION_LEN + 2];
> char *stripped = NULL;
> - size_t len;
> + ssize_t len;
> ssize_t ret;
>
> - len = strlcpy(buf, page, sizeof(buf));
> - if (len < sizeof(buf)) {
> - /* Strip any newline added from userspace. */
> - stripped = strstrip(buf);
> - len = strlen(stripped);
> - }
> - if (len > INQUIRY_REVISION_LEN) {
> + len = strscpy(buf, page, sizeof(buf));
> + if (len == -E2BIG) {
> pr_err("Emulated T10 Revision exceeds INQUIRY_REVISION_LEN: "
> __stringify(INQUIRY_REVISION_LEN)
> "\n");
>
AFAICS, you are not only replacing strlcpy with strscpy, but also remove
stripping of possible trailing '\n', and remove the necessary length
check of the remaining string.
-Bodo
next prev parent reply other threads:[~2021-02-22 16:01 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-22 15:12 [PATCH 00/20] Manual replacement of all strlcpy in favor of strscpy Romain Perier
2021-02-22 15:12 ` [PATCH 01/20] cgroup: Manual replacement of the deprecated strlcpy() with return values Romain Perier
2021-02-23 16:13 ` Michal Koutný
2021-02-22 15:12 ` [PATCH 02/20] crypto: " Romain Perier
2021-03-04 4:37 ` Herbert Xu
2021-02-22 15:12 ` [PATCH 03/20] devlink: " Romain Perier
2021-02-23 0:56 ` Jakub Kicinski
2021-02-22 15:12 ` [PATCH 04/20] dma-buf: " Romain Perier
2021-02-22 15:12 ` [PATCH 05/20] kobject: " Romain Perier
2021-02-22 15:12 ` [PATCH 06/20] ima: " Romain Perier
2021-03-02 13:29 ` Mimi Zohar
2021-02-22 15:12 ` [PATCH 07/20] SUNRPC: " Romain Perier
2021-03-01 18:25 ` Chuck Lever
2021-02-22 15:12 ` [PATCH 08/20] kernfs: " Romain Perier
2021-02-22 15:12 ` [PATCH 09/20] m68k/atari: " Romain Perier
2021-02-22 15:12 ` [PATCH 10/20] module: " Romain Perier
2021-02-22 15:12 ` [PATCH 11/20] hwmon: " Romain Perier
2021-02-22 15:46 ` Guenter Roeck
2021-02-28 11:50 ` Joe Perches
2021-02-22 15:12 ` [PATCH 12/20] s390/hmcdrv: " Romain Perier
2021-02-22 15:12 ` [PATCH 13/20] scsi: zfcp: " Romain Perier
2021-02-22 16:04 ` Benjamin Block
2021-02-22 15:12 ` [PATCH 14/20] target: " Romain Perier
2021-02-22 16:00 ` Bodo Stroesser [this message]
2021-02-22 18:09 ` kernel test robot
2021-02-22 15:12 ` [PATCH 15/20] ALSA: usb-audio: " Romain Perier
2021-02-22 15:39 ` Takashi Iwai
2021-02-22 15:12 ` [PATCH 16/20] tracing/probe: " Romain Perier
2021-02-22 17:49 ` Steven Rostedt
2021-02-22 15:12 ` [PATCH 17/20] vt: " Romain Perier
2021-02-26 9:49 ` Jiri Slaby
2021-02-22 15:12 ` [PATCH 18/20] usb: gadget: f_midi: " Romain Perier
2021-02-22 15:12 ` [PATCH 19/20] usbip: usbip_host: " Romain Perier
2021-02-22 16:21 ` Shuah Khan
2021-02-28 9:03 ` Sergei Shtylyov
2021-02-22 15:12 ` [PATCH 20/20] s390/watchdog: " Romain Perier
2021-02-22 15:55 ` Guenter Roeck
2021-02-22 16:36 ` [PATCH 00/20] Manual replacement of all strlcpy in favor of strscpy Shuah Khan
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