Re: [PATCH v15 08/11] Smack: implement setselfattr and getselfattr hooks
From: Mickaël Salaün <mic@digikod.net>
Date: 2023-10-03 14:28:24
Also in:
linux-api, lkml
On Tue, Sep 12, 2023 at 01:56:53PM -0700, Casey Schaufler wrote:
quoted hunk ↗ jump to hunk
Implement Smack support for security_[gs]etselfattr. Refactor the setprocattr hook to avoid code duplication. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com> --- security/smack/smack_lsm.c | 95 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 90 insertions(+), 5 deletions(-)diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index f73f9a2834eb..12160d060cc1 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c@@ -3626,6 +3626,46 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) return; } +/** + * smack_getselfattr - Smack current process attribute + * @attr: which attribute to fetch + * @ctx: buffer to receive the result + * @size: available size in, actual size out + * @flags: unused + * + * Fill the passed user space @ctx with the details of the requested + * attribute. + * + * Returns the number of attributes on success, an error code otherwise. + * There will only ever be one attribute. + */ +static int smack_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx, + size_t *size, u32 flags) +{ + struct smack_known *skp = smk_of_current(); + int total; + int slen; + int rc; + + if (attr != LSM_ATTR_CURRENT) + return -EOPNOTSUPP; + + slen = strlen(skp->smk_known) + 1;
+ total = ALIGN(slen + sizeof(*ctx), 8); + if (total > *size) + rc = -E2BIG; + else if (ctx) + rc = lsm_fill_user_ctx(ctx, skp->smk_known, slen, LSM_ID_SMACK, + 0); + else + rc = 1;
Can we move these checks into lsm_fill_user_ctx()? They are similar for AppArmor and SELinux.
+ + *size = total; + if (rc >= 0) + return 1; + return rc; +}