[ Upstream commit 63d5429f68a3d4c4aa27e65a05196c17f86c41d6 ]
Using strncpy() on NUL-terminated strings are deprecated. To avoid possible forming of non-terminated string strscpy() should be used.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
CC: stable@vger.kernel.org # 4.9+ Signed-off-by: Artem Chernyshev artem.chernyshev@red-soft.ru Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/ioctl.c | 9 +++------ fs/btrfs/rcu-string.h | 6 +++++- 2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index a17076a05c4d..fc335b5e44df 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3401,13 +3401,10 @@ static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info, di_args->bytes_used = btrfs_device_get_bytes_used(dev); 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; - } else { + if (dev->name) + strscpy(di_args->path, rcu_str_deref(dev->name), sizeof(di_args->path)); + else di_args->path[0] = '\0'; - }
out: rcu_read_unlock(); diff --git a/fs/btrfs/rcu-string.h b/fs/btrfs/rcu-string.h index 5c1a617eb25d..5c2b66d155ef 100644 --- a/fs/btrfs/rcu-string.h +++ b/fs/btrfs/rcu-string.h @@ -18,7 +18,11 @@ 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); + /* Warn if the source got unexpectedly truncated. */ + if (WARN_ON(strscpy(ret->str, src, len) < 0)) { + kfree(ret); + return NULL; + } return ret; }