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apparmor: handle idmapped mounts

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The i_uid and i_gid are mostly used when logging for AppArmor. This is
broken in a bunch of places where the global root id is reported instead
of the i_uid or i_gid of the file. Nonetheless, be kind and log the
mapped inode if we're coming from an idmapped mount. If the initial user
namespace is passed nothing changes so non-idmapped mounts will see
identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-26-christian.brauner@ubuntu.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This commit is contained in:
Christian Brauner 2021-01-21 14:19:44 +01:00
parent 549c729771
commit 3cee6079f6
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
3 changed files with 24 additions and 10 deletions
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9
security/apparmor/domain.c
View File

@ -10,12 +10,14 @@
#include <linux/errno.h>
#include <linux/fdtable.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/syscalls.h>
#include <linux/tracehook.h>
#include <linux/personality.h>
#include <linux/xattr.h>
#include <linux/user_namespace.h>
#include "include/audit.h"
#include "include/apparmorfs.h"
@ -858,8 +860,10 @@ int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
const char *info = NULL;
int error = 0;
bool unsafe = false;
kuid_t i_uid = i_uid_into_mnt(file_mnt_user_ns(bprm->file),
file_inode(bprm->file));
struct path_cond cond = {
file_inode(bprm->file)->i_uid,
i_uid,
file_inode(bprm->file)->i_mode
};
@ -967,8 +971,7 @@ audit:
error = fn_for_each(label, profile,
aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
bprm->filename, NULL, new,
file_inode(bprm->file)->i_uid, info,
error));
i_uid, info, error));
aa_put_label(new);
goto done;
}

4
security/apparmor/file.c
View File

@ -11,6 +11,8 @@
#include <linux/tty.h>
#include <linux/fdtable.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include "include/apparmor.h"
#include "include/audit.h"
@ -509,7 +511,7 @@ static int __file_path_perm(const char *op, struct aa_label *label,
struct aa_profile *profile;
struct aa_perms perms = {};
struct path_cond cond = {
.uid = file_inode(file)->i_uid,
.uid = i_uid_into_mnt(file_mnt_user_ns(file), file_inode(file)),
.mode = file_inode(file)->i_mode
};
char *buffer;

17
security/apparmor/lsm.c
View File

@ -224,7 +224,9 @@ static int common_perm(const char *op, const struct path *path, u32 mask,
*/
static int common_perm_cond(const char *op, const struct path *path, u32 mask)
{
struct path_cond cond = { d_backing_inode(path->dentry)->i_uid,
struct user_namespace *mnt_userns = mnt_user_ns(path->mnt);
struct path_cond cond = {
i_uid_into_mnt(mnt_userns, d_backing_inode(path->dentry)),
d_backing_inode(path->dentry)->i_mode
};
@ -266,12 +268,13 @@ static int common_perm_rm(const char *op, const struct path *dir,
struct dentry *dentry, u32 mask)
{
struct inode *inode = d_backing_inode(dentry);
struct user_namespace *mnt_userns = mnt_user_ns(dir->mnt);
struct path_cond cond = { };
if (!inode || !path_mediated_fs(dentry))
return 0;
cond.uid = inode->i_uid;
cond.uid = i_uid_into_mnt(mnt_userns, inode);
cond.mode = inode->i_mode;
return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
@ -361,11 +364,13 @@ static int apparmor_path_rename(const struct path *old_dir, struct dentry *old_d
label = begin_current_label_crit_section();
if (!unconfined(label)) {
struct user_namespace *mnt_userns = mnt_user_ns(old_dir->mnt);
struct path old_path = { .mnt = old_dir->mnt,
.dentry = old_dentry };
struct path new_path = { .mnt = new_dir->mnt,
.dentry = new_dentry };
struct path_cond cond = { d_backing_inode(old_dentry)->i_uid,
struct path_cond cond = {
i_uid_into_mnt(mnt_userns, d_backing_inode(old_dentry)),
d_backing_inode(old_dentry)->i_mode
};
@ -420,8 +425,12 @@ static int apparmor_file_open(struct file *file)
label = aa_get_newest_cred_label(file->f_cred);
if (!unconfined(label)) {
struct user_namespace *mnt_userns = file_mnt_user_ns(file);
struct inode *inode = file_inode(file);
struct path_cond cond = { inode->i_uid, inode->i_mode };
struct path_cond cond = {
i_uid_into_mnt(mnt_userns, inode),
inode->i_mode
};
error = aa_path_perm(OP_OPEN, label, &file->f_path, 0,
aa_map_file_to_perms(file), &cond);