| Message ID | 20210618005830.1819887-1-lsahlber@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | cifs: avoid extra calls in posix_info_parse | expand |
Don't we have a secondary problem (have you been able to pull up a
more complete coverity explanation of the warning - I just see minimal
info on the line numbers of the two functions returning -1)?
e.g. if posix_info_sid_size returns -1, posix_info_parse returns -1
... but we don't check for the rc in one of the callers
cifs_posix_to_fattr
/* Fill a cifs_fattr struct with info from SMB_FIND_FILE_POSIX_INFO. */
static void
cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info,
struct cifs_sb_info *cifs_sb)
{
struct smb2_posix_info_parsed parsed;
posix_info_parse(info, NULL, &parsed);
... NEED TO CHECK RC HERE ...
memset(fattr, 0, sizeof(*fattr));
...
On Thu, Jun 17, 2021 at 7:58 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote:
>
> In posix_info_parse() we call posix_info_sid_size twice for each of the owner and the group
> sid. The first time to check that it is valid, i.e. >= 0 and the second time
> to just pass it in as a length to memcpy().
> As this is a pure function we know that it can not be negative the second time and this
> is technically a false warning in coverity.
> However, as it is a pure function we are just wasting cycles by calling it a second time.
> Record the length from the first time we call it and save some cycles as well as make
> Coverity happy.
>
> Addresses-Coverity-ID: 1491379 ("Argument can not be negative")
>
> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
> fs/cifs/smb2pdu.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index c205f93e0a10..4a244cc4e902 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -4498,7 +4498,7 @@ int posix_info_parse(const void *beg, const void *end,
>
> {
> int total_len = 0;
> - int sid_len;
> + int owner_len, group_len;
> int name_len;
> const void *owner_sid;
> const void *group_sid;
> @@ -4521,17 +4521,17 @@ int posix_info_parse(const void *beg, const void *end,
>
> /* check owner sid */
> owner_sid = beg + total_len;
> - sid_len = posix_info_sid_size(owner_sid, end);
> - if (sid_len < 0)
> + owner_len = posix_info_sid_size(owner_sid, end);
> + if (owner_len < 0)
> return -1;
> - total_len += sid_len;
> + total_len += owner_len;
>
> /* check group sid */
> group_sid = beg + total_len;
> - sid_len = posix_info_sid_size(group_sid, end);
> - if (sid_len < 0)
> + group_len = posix_info_sid_size(group_sid, end);
> + if (group_len < 0)
> return -1;
> - total_len += sid_len;
> + total_len += group_len;
>
> /* check name len */
> if (beg + total_len + 4 > end)
> @@ -4552,10 +4552,8 @@ int posix_info_parse(const void *beg, const void *end,
> out->size = total_len;
> out->name_len = name_len;
> out->name = name;
> - memcpy(&out->owner, owner_sid,
> - posix_info_sid_size(owner_sid, end));
> - memcpy(&out->group, group_sid,
> - posix_info_sid_size(group_sid, end));
> + memcpy(&out->owner, owner_sid, owner_len);
> + memcpy(&out->group, group_sid, group_len);
> }
> return total_len;
> }
> --
> 2.30.2
>
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index c205f93e0a10..4a244cc4e902 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -4498,7 +4498,7 @@ int posix_info_parse(const void *beg, const void *end, { int total_len = 0; - int sid_len; + int owner_len, group_len; int name_len; const void *owner_sid; const void *group_sid; @@ -4521,17 +4521,17 @@ int posix_info_parse(const void *beg, const void *end, /* check owner sid */ owner_sid = beg + total_len; - sid_len = posix_info_sid_size(owner_sid, end); - if (sid_len < 0) + owner_len = posix_info_sid_size(owner_sid, end); + if (owner_len < 0) return -1; - total_len += sid_len; + total_len += owner_len; /* check group sid */ group_sid = beg + total_len; - sid_len = posix_info_sid_size(group_sid, end); - if (sid_len < 0) + group_len = posix_info_sid_size(group_sid, end); + if (group_len < 0) return -1; - total_len += sid_len; + total_len += group_len; /* check name len */ if (beg + total_len + 4 > end) @@ -4552,10 +4552,8 @@ int posix_info_parse(const void *beg, const void *end, out->size = total_len; out->name_len = name_len; out->name = name; - memcpy(&out->owner, owner_sid, - posix_info_sid_size(owner_sid, end)); - memcpy(&out->group, group_sid, - posix_info_sid_size(group_sid, end)); + memcpy(&out->owner, owner_sid, owner_len); + memcpy(&out->group, group_sid, group_len); } return total_len; }
In posix_info_parse() we call posix_info_sid_size twice for each of the owner and the group sid. The first time to check that it is valid, i.e. >= 0 and the second time to just pass it in as a length to memcpy(). As this is a pure function we know that it can not be negative the second time and this is technically a false warning in coverity. However, as it is a pure function we are just wasting cycles by calling it a second time. Record the length from the first time we call it and save some cycles as well as make Coverity happy. Addresses-Coverity-ID: 1491379 ("Argument can not be negative") Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> --- fs/cifs/smb2pdu.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-)