From 949b9c3d4263c9b7c2448588afce37becd58e1ad Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Thu, 23 Jan 2014 15:56:15 -0800 Subject: [PATCH] userns: relax the posix_acl_valid() checks So far, POSIX ACLs are using a canonical representation that keeps all ACL entries in a strict order; the ACL_USER and ACL_GROUP entries for specific users and groups are ordered by user and group identifier, respectively. The user-space code provides ACL entries in this order; the kernel verifies that the ACL entry order is correct in posix_acl_valid(). User namespaces allow to arbitrary map user and group identifiers which can cause the ACL_USER and ACL_GROUP entry order to differ between user space and the kernel; posix_acl_valid() would then fail. Work around this by allowing ACL_USER and ACL_GROUP entries to be in any order in the kernel. The effect is only minor: file permission checks will pick the first matching ACL_USER entry, and check all matching ACL_GROUP entries. (The libacl user-space library and getfacl / setfacl tools will not create ACLs with duplicate user or group idenfifiers; they will handle ACLs with entries in an arbitrary order correctly.) Signed-off-by: Andreas Gruenbacher Cc: Eric W. Biederman Cc: Theodore Tso Cc: Christoph Hellwig Cc: Andreas Dilger Cc: Jan Kara Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/posix_acl.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 021e7c069b86..551e61ba15b6 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -149,8 +149,6 @@ posix_acl_valid(const struct posix_acl *acl) { const struct posix_acl_entry *pa, *pe; int state = ACL_USER_OBJ; - kuid_t prev_uid = INVALID_UID; - kgid_t prev_gid = INVALID_GID; int needs_mask = 0; FOREACH_ACL_ENTRY(pa, acl, pe) { @@ -169,10 +167,6 @@ posix_acl_valid(const struct posix_acl *acl) return -EINVAL; if (!uid_valid(pa->e_uid)) return -EINVAL; - if (uid_valid(prev_uid) && - uid_lte(pa->e_uid, prev_uid)) - return -EINVAL; - prev_uid = pa->e_uid; needs_mask = 1; break; @@ -188,10 +182,6 @@ posix_acl_valid(const struct posix_acl *acl) return -EINVAL; if (!gid_valid(pa->e_gid)) return -EINVAL; - if (gid_valid(prev_gid) && - gid_lte(pa->e_gid, prev_gid)) - return -EINVAL; - prev_gid = pa->e_gid; needs_mask = 1; break; -- 2.20.1