5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ondrej Mosnacek <omosnace@xxxxxxxxxx> 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@xxxxxxxxxxxxxxx Reported-by: Stephen Smalley <stephen.smalley.work@xxxxxxxxx> Link: https://lore.kernel.org/selinux/CAEjxPJ4ev-pasUwGx48fDhnmjBnq_Wh90jYPwRQRAqXxmOKD4Q@xxxxxxxxxxxxxx/ 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@xxxxxxxxxx> Reviewed-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- security/security.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) --- a/security/security.c +++ b/security/security.c @@ -2098,7 +2098,19 @@ 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);
