| Message ID | 1438689218-6921-11-git-send-email-agruenba@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 04, 2015 at 01:53:08PM +0200, Andreas Gruenbacher wrote: > A richacl roughly grants a requested access if the NFSv4 acl in the > richacl grants the requested permissions according to the NFSv4 > permission check algorithm and the file mask that applies to the process > includes the requested permissions. > > Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> > --- > fs/Makefile | 2 +- > fs/richacl_inode.c | 146 ++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/richacl.h | 3 + > 3 files changed, 150 insertions(+), 1 deletion(-) > create mode 100644 fs/richacl_inode.c > > diff --git a/fs/Makefile b/fs/Makefile > index ddc43d8..1305047 100644 > --- a/fs/Makefile > +++ b/fs/Makefile > @@ -48,7 +48,7 @@ obj-$(CONFIG_SYSCTL) += drop_caches.o > > obj-$(CONFIG_FHANDLE) += fhandle.o > obj-$(CONFIG_FS_RICHACL) += richacl.o > -richacl-y := richacl_base.o > +richacl-y := richacl_base.o richacl_inode.o > > obj-y += quota/ > > diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c > new file mode 100644 > index 0000000..6d94e064 > --- /dev/null > +++ b/fs/richacl_inode.c > @@ -0,0 +1,146 @@ > +/* > + * Copyright (C) 2010 Novell, Inc. > + * Copyright (C) 2015 Red Hat, Inc. > + * Written by Andreas Gruenbacher <agruen@kernel.org> > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU General Public License as published by the > + * Free Software Foundation; either version 2, or (at your option) any > + * later version. > + * > + * This program is distributed in the hope that it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * General Public License for more details. > + */ > + > +#include <linux/sched.h> > +#include <linux/module.h> > +#include <linux/fs.h> > +#include <linux/slab.h> > +#include <linux/richacl.h> > + > +/** > + * richacl_permission - richacl permission check algorithm > + * @inode: inode to check > + * @acl: rich acl of the inode > + * @want: requested access (MAY_* flags) > + * > + * Checks if the current process is granted @mask flags in @acl. > + */ > +int > +richacl_permission(struct inode *inode, const struct richacl *acl, > + int want) > +{ > + const struct richace *ace; > + unsigned int mask = richacl_want_to_mask(want); > + unsigned int requested = mask, denied = 0; > + int in_owning_group = in_group_p(inode->i_gid); > + int in_owner_or_group_class = in_owning_group; > + > + /* > + * A process is > + * - in the owner file class if it owns the file, > + * - in the group file class if it is in the file's owning group or > + * it matches any of the user or group entries, and > + * - in the other file class otherwise. > + * The file class is only relevant for determining which file mask to > + * apply, which only happens for masked acls. > + */ > + if (acl->a_flags & RICHACL_MASKED) { > + if ((acl->a_flags & RICHACL_WRITE_THROUGH) && > + uid_eq(current_fsuid(), inode->i_uid)) { > + denied = requested & ~acl->a_owner_mask; > + goto out; > + } > + } else { > + /* > + * We don't care which class the process is in when the acl is > + * not masked. > + */ > + in_owner_or_group_class = 1; So why bother setting it at all, then? Oh, I see, it lets you break out of the loop below earlier. OK. Patch makes sense to me, ACK. --b. > + } > + > + /* > + * Check if the acl grants the requested access and determine which > + * file class the process is in. > + */ > + richacl_for_each_entry(ace, acl) { > + unsigned int ace_mask = ace->e_mask; > + > + if (richace_is_inherit_only(ace)) > + continue; > + if (richace_is_owner(ace)) { > + if (!uid_eq(current_fsuid(), inode->i_uid)) > + continue; > + goto entry_matches_owner; > + } else if (richace_is_group(ace)) { > + if (!in_owning_group) > + continue; > + } else if (richace_is_unix_user(ace)) { > + if (!uid_eq(current_fsuid(), ace->e_id.uid)) > + continue; > + } else if (richace_is_unix_group(ace)) { > + if (!in_group_p(ace->e_id.gid)) > + continue; > + } else > + goto entry_matches_everyone; > + > + /* > + * Apply the group file mask to entries other than owner@ and > + * everyone@ or user entries matching the owner. This ensures > + * that we grant the same permissions as the acl computed by > + * richacl_apply_masks(). > + * > + * Without this restriction, the following richacl would grant > + * rw access to processes which are both the owner and in the > + * owning group, but not to other users in the owning group, > + * which could not be represented without masks: > + * > + * owner:rw::mask > + * group@:rw::allow > + */ > + if ((acl->a_flags & RICHACL_MASKED) && richace_is_allow(ace)) > + ace_mask &= acl->a_group_mask; > + > +entry_matches_owner: > + /* The process is in the owner or group file class. */ > + in_owner_or_group_class = 1; > + > +entry_matches_everyone: > + /* Check which mask flags the ACE allows or denies. */ > + if (richace_is_deny(ace)) > + denied |= ace_mask & mask; > + mask &= ~ace_mask; > + > + /* > + * Keep going until we know which file class > + * the process is in. > + */ > + if (!mask && in_owner_or_group_class) > + break; > + } > + denied |= mask; > + > + if (acl->a_flags & RICHACL_MASKED) { > + /* > + * The file class a process is in determines which file mask > + * applies. Check if that file mask also grants the requested > + * access. > + */ > + if (uid_eq(current_fsuid(), inode->i_uid)) > + denied |= requested & ~acl->a_owner_mask; > + else if (in_owner_or_group_class) > + denied |= requested & ~acl->a_group_mask; > + else { > + if (acl->a_flags & RICHACL_WRITE_THROUGH) > + denied = requested & ~acl->a_other_mask; > + else > + denied |= requested & ~acl->a_other_mask; > + } > + } > + > +out: > + return denied ? -EACCES : 0; > +} > +EXPORT_SYMBOL_GPL(richacl_permission); > diff --git a/include/linux/richacl.h b/include/linux/richacl.h > index 8df6d93..756b711 100644 > --- a/include/linux/richacl.h > +++ b/include/linux/richacl.h > @@ -306,4 +306,7 @@ extern unsigned int richacl_want_to_mask(unsigned int); > extern void richacl_compute_max_masks(struct richacl *, kuid_t); > extern struct richacl *richacl_chmod(struct richacl *, mode_t); > > +/* richacl_inode.c */ > +extern int richacl_permission(struct inode *, const struct richacl *, int); > + > #endif /* __RICHACL_H */ > -- > 2.5.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2015-08-28 23:49 GMT+02:00 J. Bruce Fields <bfields@fieldses.org>: > On Tue, Aug 04, 2015 at 01:53:08PM +0200, Andreas Gruenbacher wrote: >> + /* >> + * We don't care which class the process is in when the acl is >> + * not masked. >> + */ >> + in_owner_or_group_class = 1; > > So why bother setting it at all, then? Oh, I see, it lets you break out > of the loop below earlier. OK. Comment changed to: /* * When the acl is not masked, there is no need to determine if * the process is in the group class and we can earlier break * out of the loop below. */ > Patch makes sense to me, ACK. Thanks, Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, Aug 29, 2015 at 12:06:22AM +0200, Andreas Grünbacher wrote: > 2015-08-28 23:49 GMT+02:00 J. Bruce Fields <bfields@fieldses.org>: > > On Tue, Aug 04, 2015 at 01:53:08PM +0200, Andreas Gruenbacher wrote: > >> + /* > >> + * We don't care which class the process is in when the acl is > >> + * not masked. > >> + */ > >> + in_owner_or_group_class = 1; > > > > So why bother setting it at all, then? Oh, I see, it lets you break out > > of the loop below earlier. OK. > > Comment changed to: > > /* > * When the acl is not masked, there is no need to determine if > * the process is in the group class and we can earlier break > * out of the loop below. > */ makes sense, just replace "earlier break out" by "break out earlier". > > > Patch makes sense to me, ACK. > > Thanks, > Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/Makefile b/fs/Makefile index ddc43d8..1305047 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -48,7 +48,7 @@ obj-$(CONFIG_SYSCTL) += drop_caches.o obj-$(CONFIG_FHANDLE) += fhandle.o obj-$(CONFIG_FS_RICHACL) += richacl.o -richacl-y := richacl_base.o +richacl-y := richacl_base.o richacl_inode.o obj-y += quota/ diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c new file mode 100644 index 0000000..6d94e064 --- /dev/null +++ b/fs/richacl_inode.c @@ -0,0 +1,146 @@ +/* + * Copyright (C) 2010 Novell, Inc. + * Copyright (C) 2015 Red Hat, Inc. + * Written by Andreas Gruenbacher <agruen@kernel.org> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +#include <linux/sched.h> +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/richacl.h> + +/** + * richacl_permission - richacl permission check algorithm + * @inode: inode to check + * @acl: rich acl of the inode + * @want: requested access (MAY_* flags) + * + * Checks if the current process is granted @mask flags in @acl. + */ +int +richacl_permission(struct inode *inode, const struct richacl *acl, + int want) +{ + const struct richace *ace; + unsigned int mask = richacl_want_to_mask(want); + unsigned int requested = mask, denied = 0; + int in_owning_group = in_group_p(inode->i_gid); + int in_owner_or_group_class = in_owning_group; + + /* + * A process is + * - in the owner file class if it owns the file, + * - in the group file class if it is in the file's owning group or + * it matches any of the user or group entries, and + * - in the other file class otherwise. + * The file class is only relevant for determining which file mask to + * apply, which only happens for masked acls. + */ + if (acl->a_flags & RICHACL_MASKED) { + if ((acl->a_flags & RICHACL_WRITE_THROUGH) && + uid_eq(current_fsuid(), inode->i_uid)) { + denied = requested & ~acl->a_owner_mask; + goto out; + } + } else { + /* + * We don't care which class the process is in when the acl is + * not masked. + */ + in_owner_or_group_class = 1; + } + + /* + * Check if the acl grants the requested access and determine which + * file class the process is in. + */ + richacl_for_each_entry(ace, acl) { + unsigned int ace_mask = ace->e_mask; + + if (richace_is_inherit_only(ace)) + continue; + if (richace_is_owner(ace)) { + if (!uid_eq(current_fsuid(), inode->i_uid)) + continue; + goto entry_matches_owner; + } else if (richace_is_group(ace)) { + if (!in_owning_group) + continue; + } else if (richace_is_unix_user(ace)) { + if (!uid_eq(current_fsuid(), ace->e_id.uid)) + continue; + } else if (richace_is_unix_group(ace)) { + if (!in_group_p(ace->e_id.gid)) + continue; + } else + goto entry_matches_everyone; + + /* + * Apply the group file mask to entries other than owner@ and + * everyone@ or user entries matching the owner. This ensures + * that we grant the same permissions as the acl computed by + * richacl_apply_masks(). + * + * Without this restriction, the following richacl would grant + * rw access to processes which are both the owner and in the + * owning group, but not to other users in the owning group, + * which could not be represented without masks: + * + * owner:rw::mask + * group@:rw::allow + */ + if ((acl->a_flags & RICHACL_MASKED) && richace_is_allow(ace)) + ace_mask &= acl->a_group_mask; + +entry_matches_owner: + /* The process is in the owner or group file class. */ + in_owner_or_group_class = 1; + +entry_matches_everyone: + /* Check which mask flags the ACE allows or denies. */ + if (richace_is_deny(ace)) + denied |= ace_mask & mask; + mask &= ~ace_mask; + + /* + * Keep going until we know which file class + * the process is in. + */ + if (!mask && in_owner_or_group_class) + break; + } + denied |= mask; + + if (acl->a_flags & RICHACL_MASKED) { + /* + * The file class a process is in determines which file mask + * applies. Check if that file mask also grants the requested + * access. + */ + if (uid_eq(current_fsuid(), inode->i_uid)) + denied |= requested & ~acl->a_owner_mask; + else if (in_owner_or_group_class) + denied |= requested & ~acl->a_group_mask; + else { + if (acl->a_flags & RICHACL_WRITE_THROUGH) + denied = requested & ~acl->a_other_mask; + else + denied |= requested & ~acl->a_other_mask; + } + } + +out: + return denied ? -EACCES : 0; +} +EXPORT_SYMBOL_GPL(richacl_permission); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index 8df6d93..756b711 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -306,4 +306,7 @@ extern unsigned int richacl_want_to_mask(unsigned int); extern void richacl_compute_max_masks(struct richacl *, kuid_t); extern struct richacl *richacl_chmod(struct richacl *, mode_t); +/* richacl_inode.c */ +extern int richacl_permission(struct inode *, const struct richacl *, int); + #endif /* __RICHACL_H */
A richacl roughly grants a requested access if the NFSv4 acl in the richacl grants the requested permissions according to the NFSv4 permission check algorithm and the file mask that applies to the process includes the requested permissions. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> --- fs/Makefile | 2 +- fs/richacl_inode.c | 146 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/richacl.h | 3 + 3 files changed, 150 insertions(+), 1 deletion(-) create mode 100644 fs/richacl_inode.c