On 7/19/2024 10:08 AM, Paul Moore wrote:
On Jul 11, 2024 Xu Kuohai <[email protected]> wrote:
To be consistent with most LSM hooks, convert the return value of
hook inode_getsecurity to 0 or a negative error code.
Before:
- Hook inode_getsecurity returns size of buffer on success or a
negative error code on failure.
After:
- Hook inode_getsecurity returns 0 on success or a negative error
code on failure. An output parameter @len is introduced to hold
the buffer size on success.
Signed-off-by: Xu Kuohai <[email protected]>
---
fs/xattr.c | 19 ++++++++++---------
include/linux/lsm_hook_defs.h | 3 ++-
include/linux/security.h | 12 ++++++------
security/commoncap.c | 9 ++++++---
security/security.c | 11 ++++++-----
security/selinux/hooks.c | 16 ++++++----------
security/smack/smack_lsm.c | 14 +++++++-------
7 files changed, 43 insertions(+), 41 deletions(-)
Aside from Simon's concern over variable types, I saw a few other issues
when looking at this patch (below).
diff --git a/security/commoncap.c b/security/commoncap.c
index 17d6188d22cf..ff82e2ab6f8f 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -485,7 +485,10 @@ int cap_inode_getsecurity(struct mnt_idmap *idmap,
}
out_free:
kfree(tmpbuf);
- return size;
+ if (size < 0)
+ return size;
+ *len = size;
+ return 0;
}
We should do a better job converting cap_inode_getsecurity(), create a
new local variable, e.g. 'int error', and use it to store and return the
error code instead of reusing @size. I understand that what you've done
is easier, but I'd prefer to see it done properly.
Got it
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 9cd5a8f1f6a3..70792bba24d9 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3407,7 +3407,7 @@ static int selinux_path_notify(const struct path *path,
u64 mask,
*/
static int selinux_inode_getsecurity(struct mnt_idmap *idmap,
struct inode *inode, const char *name,
- void **buffer, bool alloc)
+ bool alloc, void **buffer, u32 *len)
{
u32 size;
int error;
@@ -3440,14 +3440,14 @@ static int selinux_inode_getsecurity(struct mnt_idmap
*idmap,
&context, &size);
if (error)
return error;
- error = size;
+ *len = size;
Depending on how you choose to resolve the variable type issue, you may
be able to pass @len directly to security_sid_to_context().
Sounds great
if (alloc) {
*buffer = context;
goto out_nofree;
}
kfree(context);
out_nofree:
- return error;
+ return 0;
}
--
paul-moore.com
