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apparmor: rework perm mapping to a slightly broader set

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Signed-off-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
John Johansen 2017-05-26 15:07:22 -07:00
parent fc7e0b26b8
commit e53cfe6c7c
5 changed files with 131 additions and 51 deletions
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43
security/apparmor/file.c
View file

@ -21,6 +21,17 @@
struct file_perms nullperms;
static u32 map_mask_to_chr_mask(u32 mask)
{
u32 m = mask & PERMS_CHRS_MASK;
if (mask & AA_MAY_GETATTR)
m |= MAY_READ;
if (mask & (AA_MAY_SETATTR | AA_MAY_CHMOD | AA_MAY_CHOWN))
m |= MAY_WRITE;
return m;
}
/**
* audit_file_mask - convert mask to permission string
@ -31,29 +42,7 @@ static void audit_file_mask(struct audit_buffer *ab, u32 mask)
{
char str[10];
char *m = str;
if (mask & AA_EXEC_MMAP)
*m++ = 'm';
if (mask & (MAY_READ | AA_MAY_META_READ))
*m++ = 'r';
if (mask & (MAY_WRITE | AA_MAY_META_WRITE | AA_MAY_CHMOD |
AA_MAY_CHOWN))
*m++ = 'w';
else if (mask & MAY_APPEND)
*m++ = 'a';
if (mask & AA_MAY_CREATE)
*m++ = 'c';
if (mask & AA_MAY_DELETE)
*m++ = 'd';
if (mask & AA_MAY_LINK)
*m++ = 'l';
if (mask & AA_MAY_LOCK)
*m++ = 'k';
if (mask & MAY_EXEC)
*m++ = 'x';
*m = '\0';
aa_perm_mask_to_str(str, aa_file_perm_chrs, map_mask_to_chr_mask(mask));
audit_log_string(ab, str);
}
@ -163,10 +152,10 @@ static u32 map_old_perms(u32 old)
{
u32 new = old & 0xf;
if (old & MAY_READ)
new |= AA_MAY_META_READ;
new |= AA_MAY_GETATTR | AA_MAY_OPEN;
if (old & MAY_WRITE)
new |= AA_MAY_META_WRITE | AA_MAY_CREATE | AA_MAY_DELETE |
AA_MAY_CHMOD | AA_MAY_CHOWN;
new |= AA_MAY_SETATTR | AA_MAY_CREATE | AA_MAY_DELETE |
AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_OPEN;
if (old & 0x10)
new |= AA_MAY_LINK;
/* the old mapping lock and link_subset flags where overlaid
@ -214,7 +203,7 @@ static struct file_perms compute_perms(struct aa_dfa *dfa, unsigned int state,
perms.quiet = map_old_perms(dfa_other_quiet(dfa, state));
perms.xindex = dfa_other_xindex(dfa, state);
}
perms.allow |= AA_MAY_META_READ;
perms.allow |= AA_MAY_GETATTR;
/* change_profile wasn't determined by ownership in old mapping */
if (ACCEPT_TABLE(dfa)[state] & 0x80000000)

5
security/apparmor/include/file.h
View file

@ -22,10 +22,11 @@
struct aa_profile;
struct path;
#define mask_mode_t(X) (X & (MAY_EXEC | MAY_WRITE | MAY_READ | MAY_APPEND))
#define AA_AUDIT_FILE_MASK (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND |\
AA_MAY_CREATE | AA_MAY_DELETE | \
AA_MAY_META_READ | AA_MAY_META_WRITE | \
AA_MAY_GETATTR | AA_MAY_SETATTR | \
AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \
AA_EXEC_MMAP | AA_MAY_LINK)
@ -37,7 +38,7 @@ struct path;
* ctx struct will expand in the future so we keep the struct.
*/
struct aa_file_ctx {
u16 allow;
u32 allow;
};
/**

65
security/apparmor/include/perms.h
View file

@ -16,25 +16,56 @@
#include <linux/fs.h>
/*
* We use MAY_EXEC, MAY_WRITE, MAY_READ, MAY_APPEND and the following flags
* for profile permissions
*/
#define AA_MAY_CREATE 0x0010
#define AA_MAY_DELETE 0x0020
#define AA_MAY_META_WRITE 0x0040
#define AA_MAY_META_READ 0x0080
#define AA_MAY_EXEC MAY_EXEC
#define AA_MAY_WRITE MAY_WRITE
#define AA_MAY_READ MAY_READ
#define AA_MAY_APPEND MAY_APPEND
#define AA_MAY_CHMOD 0x0100
#define AA_MAY_CHOWN 0x0200
#define AA_MAY_LOCK 0x0400
#define AA_EXEC_MMAP 0x0800
#define AA_MAY_CREATE 0x0010
#define AA_MAY_DELETE 0x0020
#define AA_MAY_OPEN 0x0040
#define AA_MAY_RENAME 0x0080 /* pair */
#define AA_MAY_LINK 0x1000
#define AA_LINK_SUBSET AA_MAY_LOCK /* overlaid */
#define AA_MAY_ONEXEC 0x40000000 /* exec allows onexec */
#define AA_MAY_CHANGE_PROFILE 0x80000000
#define AA_MAY_CHANGEHAT 0x80000000 /* ctrl auditing only */
#define AA_MAY_SETATTR 0x0100 /* meta write */
#define AA_MAY_GETATTR 0x0200 /* meta read */
#define AA_MAY_SETCRED 0x0400 /* security cred/attr */
#define AA_MAY_GETCRED 0x0800
#define AA_MAY_CHMOD 0x1000 /* pair */
#define AA_MAY_CHOWN 0x2000 /* pair */
#define AA_MAY_CHGRP 0x4000 /* pair */
#define AA_MAY_LOCK 0x8000 /* LINK_SUBSET overlaid */
#define AA_EXEC_MMAP 0x00010000
#define AA_MAY_MPROT 0x00020000 /* extend conditions */
#define AA_MAY_LINK 0x00040000 /* pair */
#define AA_MAY_SNAPSHOT 0x00080000 /* pair */
#define AA_MAY_DELEGATE
#define AA_CONT_MATCH 0x08000000
#define AA_MAY_STACK 0x10000000
#define AA_MAY_ONEXEC 0x20000000 /* either stack or change_profile */
#define AA_MAY_CHANGE_PROFILE 0x40000000
#define AA_MAY_CHANGEHAT 0x80000000
#define AA_LINK_SUBSET AA_MAY_LOCK /* overlaid */
#define PERMS_CHRS_MASK (MAY_READ | MAY_WRITE | AA_MAY_CREATE | \
AA_MAY_DELETE | AA_MAY_LINK | AA_MAY_LOCK | \
AA_MAY_EXEC | AA_EXEC_MMAP | AA_MAY_APPEND)
#define PERMS_NAMES_MASK (PERMS_CHRS_MASK | AA_MAY_OPEN | AA_MAY_RENAME | \
AA_MAY_SETATTR | AA_MAY_GETATTR | AA_MAY_SETCRED | \
AA_MAY_GETCRED | AA_MAY_CHMOD | AA_MAY_CHOWN | \
AA_MAY_CHGRP | AA_MAY_MPROT | AA_MAY_SNAPSHOT | \
AA_MAY_STACK | AA_MAY_ONEXEC | \
AA_MAY_CHANGE_PROFILE | AA_MAY_CHANGEHAT)
extern const char aa_file_perm_chrs[];
extern const char *aa_file_perm_names[];
void aa_perm_mask_to_str(char *str, const char *chrs, u32 mask);
#endif /* __AA_PERM_H */

59
security/apparmor/lib.c
View file

@ -129,6 +129,65 @@ void aa_info_message(const char *str)
printk(KERN_INFO "AppArmor: %s\n", str);
}
const char aa_file_perm_chrs[] = "xwracd km l ";
const char *aa_file_perm_names[] = {
"exec",
"write",
"read",
"append",
"create",
"delete",
"open",
"rename",
"setattr",
"getattr",
"setcred",
"getcred",
"chmod",
"chown",
"chgrp",
"lock",
"mmap",
"mprot",
"link",
"snapshot",
"unknown",
"unknown",
"unknown",
"unknown",
"unknown",
"unknown",
"unknown",
"unknown",
"stack",
"change_onexec",
"change_profile",
"change_hat",
};
/**
* aa_perm_mask_to_str - convert a perm mask to its short string
* @str: character buffer to store string in (at least 10 characters)
* @mask: permission mask to convert
*/
void aa_perm_mask_to_str(char *str, const char *chrs, u32 mask)
{
unsigned int i, perm = 1;
for (i = 0; i < 32; perm <<= 1, i++) {
if (mask & perm)
*str++ = chrs[i];
}
*str = '\0';
}
/**
* aa_policy_init - initialize a policy structure
* @policy: policy to initialize (NOT NULL)

10
security/apparmor/lsm.c
View file

@ -278,7 +278,7 @@ static int apparmor_path_mknod(const struct path *dir, struct dentry *dentry,
static int apparmor_path_truncate(const struct path *path)
{
return common_perm_cond(OP_TRUNC, path, MAY_WRITE | AA_MAY_META_WRITE);
return common_perm_cond(OP_TRUNC, path, MAY_WRITE | AA_MAY_SETATTR);
}
static int apparmor_path_symlink(const struct path *dir, struct dentry *dentry,
@ -323,12 +323,12 @@ static int apparmor_path_rename(const struct path *old_dir, struct dentry *old_d
};
error = aa_path_perm(OP_RENAME_SRC, profile, &old_path, 0,
MAY_READ | AA_MAY_META_READ | MAY_WRITE |
AA_MAY_META_WRITE | AA_MAY_DELETE,
MAY_READ | AA_MAY_GETATTR | MAY_WRITE |
AA_MAY_SETATTR | AA_MAY_DELETE,
&cond);
if (!error)
error = aa_path_perm(OP_RENAME_DEST, profile, &new_path,
0, MAY_WRITE | AA_MAY_META_WRITE |
0, MAY_WRITE | AA_MAY_SETATTR |
AA_MAY_CREATE, &cond);
}
@ -347,7 +347,7 @@ static int apparmor_path_chown(const struct path *path, kuid_t uid, kgid_t gid)
static int apparmor_inode_getattr(const struct path *path)
{
return common_perm_cond(OP_GETATTR, path, AA_MAY_META_READ);
return common_perm_cond(OP_GETATTR, path, AA_MAY_GETATTR);
}
static int apparmor_file_open(struct file *file, const struct cred *cred)