Unverified Commit 31e825c6 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!11095 exec: Fix ToCToU between perm check and set-uid/gid usage 

Merge Pull Request from: @ci-robot 
 
PR sync from: Zizhi Wo <wozizhi@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/BL6OSDOAZODXHA4XCQXBGLGW5A5EW7YY/ 
 
https://gitee.com/src-openeuler/kernel/issues/IALED4 
 
Link:https://gitee.com/openeuler/kernel/pulls/11095

 

Reviewed-by: default avatarLiu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: default avatarZhang Changzhong <zhangchangzhong@huawei.com>
parents 80b00cbd f7a7b998

fs/exec.c

+7 −1
Original line number Diff line number Diff line
@@ -1529,6 +1529,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm) 
	unsigned int mode;

	kuid_t uid;

	kgid_t gid;

	int err;



	/*

	 * Since this can be called multiple times (via prepare_binprm),
@@ -1553,12 +1554,17 @@ static void bprm_fill_uid(struct linux_binprm *bprm) 
	/* Be careful if suid/sgid is set */

	inode_lock(inode);



	/* reload atomically mode/uid/gid now that lock held */

	/* Atomically reload and check mode/uid/gid now that lock held. */

	mode = inode->i_mode;

	uid = inode->i_uid;

	gid = inode->i_gid;

	err = inode_permission(inode, MAY_EXEC);

	inode_unlock(inode);



	/* Did the exec bit vanish out from under us? Give up. */

	if (err)

		return;



	/* We ignore suid/sgid if there are no mappings for them in the ns */

	if (!kuid_has_mapping(bprm->cred->user_ns, uid) ||

		 !kgid_has_mapping(bprm->cred->user_ns, gid))