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jfs: preserve i_mode if __jfs_set_acl() fails

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When changing a file's acl mask, __jfs_set_acl() will first set the group
bits of i_mode to the value of the mask, and only then set the actual
extended attribute representing the new acl.

If the second part fails (due to lack of space, for example) and the file
had no acl attribute to begin with, the system will from now on assume
that the mask permission bits are actual group permission bits, potentially
granting access to the wrong users.

Prevent this by only changing the inode mode after the acl has been set.

Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
This commit is contained in:
Ernesto A. Fernández 2017-07-12 06:55:35 -03:00 committed by Dave Kleikamp
parent 9bcf66c72d
commit f070e5ac9b
1 changed files with 11 additions and 4 deletions
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15
fs/jfs/acl.c
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@ -108,19 +108,26 @@ int jfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
int rc;
tid_t tid;
int update_mode = 0;
umode_t mode = inode->i_mode;
tid = txBegin(inode->i_sb, 0);
mutex_lock(&JFS_IP(inode)->commit_mutex);
if (type == ACL_TYPE_ACCESS && acl) {
rc = posix_acl_update_mode(inode, &inode->i_mode, &acl);
rc = posix_acl_update_mode(inode, &mode, &acl);
if (rc)
goto end_tx;
inode->i_ctime = current_time(inode);
mark_inode_dirty(inode);
update_mode = 1;
}
rc = __jfs_set_acl(tid, inode, type, acl);
if (!rc)
if (!rc) {
if (update_mode) {
inode->i_mode = mode;
inode->i_ctime = current_time(inode);
mark_inode_dirty(inode);
}
rc = txCommit(tid, 1, &inode, 0);
}
end_tx:
txEnd(tid);
mutex_unlock(&JFS_IP(inode)->commit_mutex);