2022-11-19 08:17:19

by Artem Chernyshev

Subject: [PATCH v2] btrfs: rcu_string: Replace strncpy() with strscpy()

Using strncpy() on NUL-terminated strings are deprecated.
To avoid possible forming of non-terminated string
strscpy() could be used.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 606686eeac45 ("Btrfs: use rcu to protect device->name")
Signed-off-by: Artem Chernyshev <[email protected]>
---
V1->V2 Fixed typo in subject

fs/btrfs/rcu-string.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/rcu-string.h b/fs/btrfs/rcu-string.h
index 5c1a617eb25d..d9894da7a05a 100644
--- a/fs/btrfs/rcu-string.h
+++ b/fs/btrfs/rcu-string.h
@@ -18,7 +18,10 @@ static inline struct rcu_string *rcu_string_strdup(const char *src, gfp_t mask)
(len * sizeof(char)), mask);
if (!ret)
return ret;
- strncpy(ret->str, src, len);
+ if (WARN_ON(strscpy(ret->str, src, len) < 0)) {
+ kfree(ret);
+ return NULL;
+ }
return ret;
}

--
2.30.3

2022-11-21 19:05:47

by David Sterba

Subject: Re: [PATCH v2] btrfs: rcu_string: Replace strncpy() with strscpy()

On Sat, Nov 19, 2022 at 11:13:29AM +0300, Artem Chernyshev wrote:
> Using strncpy() on NUL-terminated strings are deprecated.
> To avoid possible forming of non-terminated string
> strscpy() could be used.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 606686eeac45 ("Btrfs: use rcu to protect device->name")
> Signed-off-by: Artem Chernyshev <[email protected]>

Added to misc-next, thanks. There's one last strncpy in
btrfs_ioctl_dev_info if you also want to convert it. The rest is strcpy
from static strings.

2022-11-22 15:49:23

by Artem Chernyshev

Subject: [PATCH v3] btrfs: Replace strncpy() with strscpy()

Using strncpy() on NUL-terminated strings are deprecated.
To avoid possible forming of non-terminated string
strscpy() could be used.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 475f63874d73 ("btrfs: new ioctls for scrub")
Fixes: 606686eeac45 ("Btrfs: use rcu to protect device->name")
Signed-off-by: Artem Chernyshev <[email protected]>
---
V1->V2 Fixed typo in subject
V2->V3 Added fix for ioctl.c

fs/btrfs/ioctl.c | 5 ++---
fs/btrfs/rcu-string.h | 5 ++++-
2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d5dd8bed1488..fdf62d514662 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3748,9 +3748,8 @@ static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info,
di_args->total_bytes = btrfs_device_get_total_bytes(dev);
memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
if (dev->name) {
- strncpy(di_args->path, rcu_str_deref(dev->name),
- sizeof(di_args->path) - 1);
- di_args->path[sizeof(di_args->path) - 1] = 0;
+ strscpy(di_args->path, rcu_str_deref(dev->name),
+ sizeof(di_args->path));
} else {
di_args->path[0] = '\0';
}
diff --git a/fs/btrfs/rcu-string.h b/fs/btrfs/rcu-string.h
index 5c1a617eb25d..d9894da7a05a 100644
--- a/fs/btrfs/rcu-string.h
+++ b/fs/btrfs/rcu-string.h
@@ -18,7 +18,10 @@ static inline struct rcu_string *rcu_string_strdup(const char *src, gfp_t mask)
(len * sizeof(char)), mask);
if (!ret)
return ret;
- strncpy(ret->str, src, len);
+ if (WARN_ON(strscpy(ret->str, src, len) < 0)) {
+ kfree(ret);
+ return NULL;
+ }
return ret;
}

--
2.30.3

2022-11-22 16:12:09

by David Sterba

Subject: Re: [PATCH v3] btrfs: Replace strncpy() with strscpy()

On Tue, Nov 22, 2022 at 05:51:08PM +0300, Artem Chernyshev wrote:
> Using strncpy() on NUL-terminated strings are deprecated.
> To avoid possible forming of non-terminated string
> strscpy() could be used.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 475f63874d73 ("btrfs: new ioctls for scrub")
> Fixes: 606686eeac45 ("Btrfs: use rcu to protect device->name")
> Signed-off-by: Artem Chernyshev <[email protected]>

Added to misc-next with minor adjustments, thanks.