From: Chuck Lever <chuck.lever@oracle.com> mainline inclusion from mainline-v6.12-rc3 commit 903dc9c43a155e0893280c7472d4a9a3a83d75a6 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBLWT7 CVE: CVE-2024-57952 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Testing shows that the EBUSY error return from mtree_alloc_cyclic() leaks into user space. The ERRORS section of "man creat(2)" says:
EBUSY O_EXCL was specified in flags and pathname refers to a block device that is in use by the system (e.g., it is mounted).
ENOSPC is closer to what applications expect in this situation. Note that the normal range of simple directory offset values is 2..2^63, so hitting this error is going to be rare to impossible. Fixes: 6faddda69f62 ("libfs: Add directory operations for stable offsets") Cc: stable@vger.kernel.org # v6.9+ Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Yang Erkun <yangerkun@huawei.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Link: https://lore.kernel.org/r/20241228175522.1854234-2-cel@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Yongjian Sun <sunyongjian1@huawei.com> --- fs/libfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/libfs.c b/fs/libfs.c index 71a1893e7b71..8f13f8b27803 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -286,8 +286,8 @@ int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry) ret = mtree_alloc_cyclic(&octx->mt, &offset, dentry, DIR_OFFSET_MIN, LONG_MAX, &octx->next_offset, GFP_KERNEL); - if (ret < 0) - return ret; + if (unlikely(ret < 0)) + return ret == -EBUSY ? -ENOSPC : ret; offset_set(dentry, offset); return 0; -- 2.39.2