diff options
| author | Oleg Drokin <green@linuxhacker.ru> | 2015-06-11 01:37:51 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-06-11 09:03:59 -0700 |
| commit | a75034345b3026f1cf5668e70688ea53184e49c1 (patch) | |
| tree | f11252b2eb7182abff4b385b659560f6480ae646 | |
| parent | d8bc89a7f34242d67e7eefade6fc0df057c34ec1 (diff) | |
staging/lustre/llite: fix ll_getname user buffer copy
strncpy_from_user could return negative values on error,
so need to take those into account.
Since ll_getname is used to get a single component name from userspace
to transfer to server as-is, there's no need to allocate 4k buffer
as done by __getname. Allocate NAME_MAX+1 buffer instead to ensure
we have enough for a null terminated max valid length buffer.
This was discovered by Al Viro in https://lkml.org/lkml/2015/4/11/243
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/lustre/lustre/llite/dir.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/drivers/staging/lustre/lustre/llite/dir.c b/drivers/staging/lustre/lustre/llite/dir.c index 87a042c0433a..50d685b0dda0 100644 --- a/drivers/staging/lustre/lustre/llite/dir.c +++ b/drivers/staging/lustre/lustre/llite/dir.c @@ -1213,29 +1213,34 @@ out: return rc; } -static char * -ll_getname(const char __user *filename) +/* This function tries to get a single name component, + * to send to the server. No actual path traversal involved, + * so we limit to NAME_MAX */ +static char *ll_getname(const char __user *filename) { int ret = 0, len; - char *tmp = __getname(); + char *tmp; + tmp = kzalloc(NAME_MAX + 1, GFP_KERNEL); if (!tmp) return ERR_PTR(-ENOMEM); - len = strncpy_from_user(tmp, filename, PATH_MAX); - if (len == 0) + len = strncpy_from_user(tmp, filename, NAME_MAX + 1); + if (len < 0) + ret = len; + else if (len == 0) ret = -ENOENT; - else if (len > PATH_MAX) + else if (len > NAME_MAX && tmp[NAME_MAX] != 0) ret = -ENAMETOOLONG; if (ret) { - __putname(tmp); + kfree(tmp); tmp = ERR_PTR(ret); } return tmp; } -#define ll_putname(filename) __putname(filename) +#define ll_putname(filename) kfree(filename) static long ll_dir_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { |