Commit 8189a56b authored by Ernesto A. Fernández's avatar Ernesto A. Fernández Committed by Greg Kroah-Hartman

ext4: preserve i_mode if __ext4_set_acl() fails

commit 397e4341 upstream.

When changing a file's acl mask, __ext4_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: default avatarErnesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent aaab6465
...@@ -189,16 +189,17 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type, ...@@ -189,16 +189,17 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
void *value = NULL; void *value = NULL;
size_t size = 0; size_t size = 0;
int error; int error;
int update_mode = 0;
umode_t mode = inode->i_mode;
switch (type) { switch (type) {
case ACL_TYPE_ACCESS: case ACL_TYPE_ACCESS:
name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS; name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
if (acl) { if (acl) {
error = posix_acl_update_mode(inode, &inode->i_mode, &acl); error = posix_acl_update_mode(inode, &mode, &acl);
if (error) if (error)
return error; return error;
inode->i_ctime = current_time(inode); update_mode = 1;
ext4_mark_inode_dirty(handle, inode);
} }
break; break;
...@@ -221,8 +222,14 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type, ...@@ -221,8 +222,14 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
value, size, 0); value, size, 0);
kfree(value); kfree(value);
if (!error) if (!error) {
set_cached_acl(inode, type, acl); set_cached_acl(inode, type, acl);
if (update_mode) {
inode->i_mode = mode;
inode->i_ctime = current_time(inode);
ext4_mark_inode_dirty(handle, inode);
}
}
return error; return error;
} }
......
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