6.1-stable review patch. If anyone has any objections, please let me know.
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From: Ondrej Mosnacek omosnace@redhat.com
commit 99b817c173cd213671daecd25ca27f56b0c7c4ec upstream.
The inode_getsecctx LSM hook has previously been corrected to have -EOPNOTSUPP instead of 0 as the default return value to fix BPF LSM behavior. However, the call_int_hook()-generated loop in security_inode_getsecctx() was left treating 0 as the neutral value, so after an LSM returns 0, the loop continues to try other LSMs, and if one of them returns a non-zero value, the function immediately returns with said value. So in a situation where SELinux and the BPF LSMs registered this hook, -EOPNOTSUPP would be incorrectly returned whenever SELinux returned 0.
Fix this by open-coding the call_int_hook() loop and making it use the correct LSM_RET_DEFAULT() value as the neutral one, similar to what other hooks do.
Cc: stable@vger.kernel.org Reported-by: Stephen Smalley stephen.smalley.work@gmail.com Link: https://lore.kernel.org/selinux/CAEjxPJ4ev-pasUwGx48fDhnmjBnq_Wh90jYPwRQRAqX... Link: https://bugzilla.redhat.com/show_bug.cgi?id=2257983 Fixes: b36995b8609a ("lsm: fix default return value for inode_getsecctx") Signed-off-by: Ondrej Mosnacek omosnace@redhat.com Reviewed-by: Casey Schaufler casey@schaufler-ca.com [PM: subject line tweak] Signed-off-by: Paul Moore paul@paul-moore.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- security/security.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)
--- a/security/security.c +++ b/security/security.c @@ -2186,7 +2186,19 @@ EXPORT_SYMBOL(security_inode_setsecctx);
int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen) { - return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, ctx, ctxlen); + struct security_hook_list *hp; + int rc; + + /* + * Only one module will provide a security context. + */ + hlist_for_each_entry(hp, &security_hook_heads.inode_getsecctx, list) { + rc = hp->hook.inode_getsecctx(inode, ctx, ctxlen); + if (rc != LSM_RET_DEFAULT(inode_getsecctx)) + return rc; + } + + return LSM_RET_DEFAULT(inode_getsecctx); } EXPORT_SYMBOL(security_inode_getsecctx);