[stgt] [PATCH] bs_sheepdog.c: fix up buffer overrun issues with unix domain socket
Hitoshi Mitake
mitake.hitoshi at gmail.com
Tue Dec 3 02:47:47 CET 2013
At Tue, 3 Dec 2013 10:28:42 +0900,
Ryusuke Konishi wrote:
>
> The current sheepdog driver still has two buffer overrun issues due to
> unsafe strncpy uses for the pathname buffer of unix domain socket:
>
> 1) The size of "sun_path" string buffer of "sockaddr_un" structure is
> 108 bytes, however, UNIX_PATH_MAX macro is locally defined as 109.
> So, the following strncpy use at connect_to_sdog_unix function
> still can be filled without a terminating null byte.
>
> strncpy(un.sun_path, path, UNIX_PATH_MAX - 1);
>
> 2) The following use of strncpy at sd_open function also has a buffer
> overrun issue because the size of ai->uds_path is the same as
> UNIX_PATH_MAX.
>
> strncpy(ai->uds_path, result, UNIX_PATH_MAX);
>
> Moreover, the local definition of UNIX_PATH_MAX, which gives the
> buffer size of unix domain socket pathname, is confusing. It is
> traditionally used to define the size of "sun_path" string buffer of
> "sockaddr_un", which is 108 bytes including a terminating null byte,
> but this local macro sets it to 109 bytes.
>
> This patch fixes up these issues.
>
> Signed-off-by: Ryusuke Konishi <konishi.ryusuke at lab.ntt.co.jp>
> Cc: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
> ---
> usr/bs_sheepdog.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
Thanks for your bugfixes, looks good to me.
Reviewed-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
Thanks,
Hitoshi
>
> diff --git a/usr/bs_sheepdog.c b/usr/bs_sheepdog.c
> index 315f3aa..43f3157 100644
> --- a/usr/bs_sheepdog.c
> +++ b/usr/bs_sheepdog.c
> @@ -220,7 +220,7 @@ struct sheepdog_fd_list {
> struct list_head list;
> };
>
> -#define UNIX_PATH_MAX (108 + 1)
> +#define UNIX_PATH_MAX 108
>
> struct sheepdog_access_info {
> int is_unix;
> @@ -398,7 +398,7 @@ static int connect_to_sdog_unix(const char *path)
>
> memset(&un, 0, sizeof(un));
> un.sun_family = AF_UNIX;
> - strncpy(un.sun_path, path, UNIX_PATH_MAX - 1);
> + strncpy(un.sun_path, path, sizeof(un.sun_path) - 1);
>
> ret = connect(fd, (const struct sockaddr *)&un, (socklen_t)sizeof(un));
> if (ret < 0) {
> @@ -967,7 +967,7 @@ static int sd_open(struct sheepdog_access_info *ai, char *filename, int flags)
> }
> break;
> case EXPECT_PATH:
> - strncpy(ai->uds_path, result, UNIX_PATH_MAX);
> + strncpy(ai->uds_path, result, UNIX_PATH_MAX - 1);
> parse_state = EXPECT_VDI;
> break;
> case EXPECT_HOST:
> --
> 1.7.9.3
>
> --
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