* [PATCH v3] scsi: target: Replace strlcpy with strscpy
@ 2023-08-31 14:36 Azeem Shaikh
2023-08-31 18:42 ` Kees Cook
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Azeem Shaikh @ 2023-08-31 14:36 UTC (permalink / raw)
To: Martin K. Petersen, Kees Cook
Cc: linux-hardening, Azeem Shaikh, linux-scsi, target-devel,
linux-kernel
strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
Direct replacement is safe here since return value of -errno
is used to check for truncation instead of sizeof(dest).
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89
Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
---
v3:
* Address readability comment.
v2:
* Replace all instances of strlcpy in this file instead of just 1.
* https://lore.kernel.org/all/20230830210724.4156575-1-azeemshaikh38@gmail.com/
v1:
* https://lore.kernel.org/all/20230830200717.4129442-1-azeemshaikh38@gmail.com/
drivers/target/target_core_configfs.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 936e5ff1b209..d5860c1c1f46 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -1392,16 +1392,16 @@ 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)) {
+ len = strscpy(buf, page, sizeof(buf));
+ if (len > 0) {
/* Strip any newline added from userspace. */
stripped = strstrip(buf);
len = strlen(stripped);
}
- if (len > INQUIRY_VENDOR_LEN) {
+ if (len < 0 || len > INQUIRY_VENDOR_LEN) {
pr_err("Emulated T10 Vendor Identification exceeds"
" INQUIRY_VENDOR_LEN: " __stringify(INQUIRY_VENDOR_LEN)
"\n");
@@ -1448,16 +1448,16 @@ 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)) {
+ len = strscpy(buf, page, sizeof(buf));
+ if (len > 0) {
/* Strip any newline added from userspace. */
stripped = strstrip(buf);
len = strlen(stripped);
}
- if (len > INQUIRY_MODEL_LEN) {
+ if (len < 0 || len > INQUIRY_MODEL_LEN) {
pr_err("Emulated T10 Vendor exceeds INQUIRY_MODEL_LEN: "
__stringify(INQUIRY_MODEL_LEN)
"\n");
@@ -1504,16 +1504,16 @@ 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)) {
+ len = strscpy(buf, page, sizeof(buf));
+ if (len > 0) {
/* Strip any newline added from userspace. */
stripped = strstrip(buf);
len = strlen(stripped);
}
- if (len > INQUIRY_REVISION_LEN) {
+ if (len < 0 || len > INQUIRY_REVISION_LEN) {
pr_err("Emulated T10 Revision exceeds INQUIRY_REVISION_LEN: "
__stringify(INQUIRY_REVISION_LEN)
"\n");
--
2.42.0.283.g2d96d420d3-goog
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v3] scsi: target: Replace strlcpy with strscpy
2023-08-31 14:36 [PATCH v3] scsi: target: Replace strlcpy with strscpy Azeem Shaikh
@ 2023-08-31 18:42 ` Kees Cook
2023-08-31 19:20 ` Azeem Shaikh
2023-09-05 9:56 ` Martin K. Petersen
2023-09-14 1:40 ` Martin K. Petersen
2 siblings, 1 reply; 6+ messages in thread
From: Kees Cook @ 2023-08-31 18:42 UTC (permalink / raw)
To: Azeem Shaikh
Cc: Martin K. Petersen, linux-hardening, linux-scsi, target-devel,
linux-kernel
On Thu, Aug 31, 2023 at 02:36:38PM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
>
> Direct replacement is safe here since return value of -errno
> is used to check for truncation instead of sizeof(dest).
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
>
> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
> ---
> v3:
> * Address readability comment.
>
> v2:
> * Replace all instances of strlcpy in this file instead of just 1.
> * https://lore.kernel.org/all/20230830210724.4156575-1-azeemshaikh38@gmail.com/
>
> v1:
> * https://lore.kernel.org/all/20230830200717.4129442-1-azeemshaikh38@gmail.com/
>
> drivers/target/target_core_configfs.c | 24 ++++++++++++------------
> 1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
> index 936e5ff1b209..d5860c1c1f46 100644
> --- a/drivers/target/target_core_configfs.c
> +++ b/drivers/target/target_core_configfs.c
> @@ -1392,16 +1392,16 @@ 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)) {
> + len = strscpy(buf, page, sizeof(buf));
> + if (len > 0) {
> /* Strip any newline added from userspace. */
> stripped = strstrip(buf);
> len = strlen(stripped);
> }
> - if (len > INQUIRY_VENDOR_LEN) {
> + if (len < 0 || len > INQUIRY_VENDOR_LEN) {
Agh, sorry I missed this before: the first "if" needs to be "len >= 0"
otherwise this:
ret = target_check_inquiry_data(stripped);
will be passing a NULL pointer...
--
Kees Cook
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v3] scsi: target: Replace strlcpy with strscpy
2023-08-31 18:42 ` Kees Cook
@ 2023-08-31 19:20 ` Azeem Shaikh
2023-08-31 21:02 ` Kees Cook
0 siblings, 1 reply; 6+ messages in thread
From: Azeem Shaikh @ 2023-08-31 19:20 UTC (permalink / raw)
To: Kees Cook
Cc: Martin K. Petersen, linux-hardening, linux-scsi, target-devel,
linux-kernel
On Thu, Aug 31, 2023 at 2:42 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Thu, Aug 31, 2023 at 02:36:38PM +0000, Azeem Shaikh wrote:
> > strlcpy() reads the entire source buffer first.
> > This read may exceed the destination size limit.
> > This is both inefficient and can lead to linear read
> > overflows if a source string is not NUL-terminated [1].
> > In an effort to remove strlcpy() completely [2], replace
> > strlcpy() here with strscpy().
> >
> > Direct replacement is safe here since return value of -errno
> > is used to check for truncation instead of sizeof(dest).
> >
> > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> > [2] https://github.com/KSPP/linux/issues/89
> >
> > Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
> > ---
> > v3:
> > * Address readability comment.
> >
> > v2:
> > * Replace all instances of strlcpy in this file instead of just 1.
> > * https://lore.kernel.org/all/20230830210724.4156575-1-azeemshaikh38@gmail.com/
> >
> > v1:
> > * https://lore.kernel.org/all/20230830200717.4129442-1-azeemshaikh38@gmail.com/
> >
> > drivers/target/target_core_configfs.c | 24 ++++++++++++------------
> > 1 file changed, 12 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
> > index 936e5ff1b209..d5860c1c1f46 100644
> > --- a/drivers/target/target_core_configfs.c
> > +++ b/drivers/target/target_core_configfs.c
> > @@ -1392,16 +1392,16 @@ 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)) {
> > + len = strscpy(buf, page, sizeof(buf));
> > + if (len > 0) {
> > /* Strip any newline added from userspace. */
> > stripped = strstrip(buf);
> > len = strlen(stripped);
> > }
> > - if (len > INQUIRY_VENDOR_LEN) {
> > + if (len < 0 || len > INQUIRY_VENDOR_LEN) {
>
> Agh, sorry I missed this before: the first "if" needs to be "len >= 0"
> otherwise this:
>
> ret = target_check_inquiry_data(stripped);
>
> will be passing a NULL pointer...
>
Hmm, the current implementation of strscpy never returns 0. If
sizeof(buf) is 0, it'll return -E2BIG. Do you still prefer that I
update this to check for len >= 0?
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v3] scsi: target: Replace strlcpy with strscpy
2023-08-31 19:20 ` Azeem Shaikh
@ 2023-08-31 21:02 ` Kees Cook
0 siblings, 0 replies; 6+ messages in thread
From: Kees Cook @ 2023-08-31 21:02 UTC (permalink / raw)
To: Azeem Shaikh
Cc: Martin K. Petersen, linux-hardening, linux-scsi, target-devel,
linux-kernel
On Thu, Aug 31, 2023 at 03:20:47PM -0400, Azeem Shaikh wrote:
> On Thu, Aug 31, 2023 at 2:42 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > On Thu, Aug 31, 2023 at 02:36:38PM +0000, Azeem Shaikh wrote:
> > > strlcpy() reads the entire source buffer first.
> > > This read may exceed the destination size limit.
> > > This is both inefficient and can lead to linear read
> > > overflows if a source string is not NUL-terminated [1].
> > > In an effort to remove strlcpy() completely [2], replace
> > > strlcpy() here with strscpy().
> > >
> > > Direct replacement is safe here since return value of -errno
> > > is used to check for truncation instead of sizeof(dest).
> > >
> > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> > > [2] https://github.com/KSPP/linux/issues/89
> > >
> > > Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
> > > ---
> > > v3:
> > > * Address readability comment.
> > >
> > > v2:
> > > * Replace all instances of strlcpy in this file instead of just 1.
> > > * https://lore.kernel.org/all/20230830210724.4156575-1-azeemshaikh38@gmail.com/
> > >
> > > v1:
> > > * https://lore.kernel.org/all/20230830200717.4129442-1-azeemshaikh38@gmail.com/
> > >
> > > drivers/target/target_core_configfs.c | 24 ++++++++++++------------
> > > 1 file changed, 12 insertions(+), 12 deletions(-)
> > >
> > > diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
> > > index 936e5ff1b209..d5860c1c1f46 100644
> > > --- a/drivers/target/target_core_configfs.c
> > > +++ b/drivers/target/target_core_configfs.c
> > > @@ -1392,16 +1392,16 @@ 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)) {
> > > + len = strscpy(buf, page, sizeof(buf));
> > > + if (len > 0) {
> > > /* Strip any newline added from userspace. */
> > > stripped = strstrip(buf);
> > > len = strlen(stripped);
> > > }
> > > - if (len > INQUIRY_VENDOR_LEN) {
> > > + if (len < 0 || len > INQUIRY_VENDOR_LEN) {
> >
> > Agh, sorry I missed this before: the first "if" needs to be "len >= 0"
> > otherwise this:
> >
> > ret = target_check_inquiry_data(stripped);
> >
> > will be passing a NULL pointer...
> >
>
> Hmm, the current implementation of strscpy never returns 0. If
> sizeof(buf) is 0, it'll return -E2BIG. Do you still prefer that I
> update this to check for len >= 0?
Oh right! Nevermind, then. Fine as-is. :)
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] scsi: target: Replace strlcpy with strscpy
2023-08-31 14:36 [PATCH v3] scsi: target: Replace strlcpy with strscpy Azeem Shaikh
2023-08-31 18:42 ` Kees Cook
@ 2023-09-05 9:56 ` Martin K. Petersen
2023-09-14 1:40 ` Martin K. Petersen
2 siblings, 0 replies; 6+ messages in thread
From: Martin K. Petersen @ 2023-09-05 9:56 UTC (permalink / raw)
To: Azeem Shaikh
Cc: Martin K. Petersen, Kees Cook, linux-hardening, linux-scsi,
target-devel, linux-kernel
Azeem,
> strlcpy() reads the entire source buffer first. This read may exceed
> the destination size limit. This is both inefficient and can lead to
> linear read overflows if a source string is not NUL-terminated [1]. In
> an effort to remove strlcpy() completely [2], replace strlcpy() here
> with strscpy().
Applied to 6.6/scsi-staging, thanks!
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] scsi: target: Replace strlcpy with strscpy
2023-08-31 14:36 [PATCH v3] scsi: target: Replace strlcpy with strscpy Azeem Shaikh
2023-08-31 18:42 ` Kees Cook
2023-09-05 9:56 ` Martin K. Petersen
@ 2023-09-14 1:40 ` Martin K. Petersen
2 siblings, 0 replies; 6+ messages in thread
From: Martin K. Petersen @ 2023-09-14 1:40 UTC (permalink / raw)
To: Kees Cook, Azeem Shaikh
Cc: Martin K . Petersen, linux-hardening, linux-scsi, target-devel,
linux-kernel
On Thu, 31 Aug 2023 14:36:38 +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
>
> [...]
Applied to 6.6/scsi-fixes, thanks!
[1/1] scsi: target: Replace strlcpy with strscpy
https://git.kernel.org/mkp/scsi/c/5c584fe6098a
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 6+ messages in thread
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2023-08-31 14:36 [PATCH v3] scsi: target: Replace strlcpy with strscpy Azeem Shaikh
2023-08-31 18:42 ` Kees Cook
2023-08-31 19:20 ` Azeem Shaikh
2023-08-31 21:02 ` Kees Cook
2023-09-05 9:56 ` Martin K. Petersen
2023-09-14 1:40 ` Martin K. Petersen
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