diff options
| author | Vasiliy Kovalev <kovalev@altlinux.org> | 2025-12-02 12:03:16 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-12-07 06:08:24 +0900 |
| commit | f77618291836168eca99e89cd175256f928f5e64 (patch) | |
| tree | 33dc014655ccbfaaeb343ac1f6a7006caa2127bb | |
| parent | 6289fc489e94c9beb6be2b502ccc263663733d72 (diff) | |
ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up
[ Upstream commit c84e125fff2615b4d9c259e762596134eddd2f27 ]
The issue was caused by dput(upper) being called before
ovl_dentry_update_reval(), while upper->d_flags was still
accessed in ovl_dentry_remote().
Move dput(upper) after its last use to prevent use-after-free.
BUG: KASAN: slab-use-after-free in ovl_dentry_remote fs/overlayfs/util.c:162 [inline]
BUG: KASAN: slab-use-after-free in ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
ovl_dentry_remote fs/overlayfs/util.c:162 [inline]
ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167
ovl_link_up fs/overlayfs/copy_up.c:610 [inline]
ovl_copy_up_one+0x2105/0x3490 fs/overlayfs/copy_up.c:1170
ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1223
ovl_rename+0x39e/0x18c0 fs/overlayfs/dir.c:1136
vfs_rename+0xf84/0x20a0 fs/namei.c:4893
...
</TASK>
Fixes: b07d5cc93e1b ("ovl: update of dentry revalidate flags after copy up")
Reported-by: syzbot+316db8a1191938280eb6@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=316db8a1191938280eb6
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
Link: https://lore.kernel.org/r/20250214215148.761147-1-kovalev@altlinux.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
[ Minor context change fixed. ]
Signed-off-by: Bin Lan <lanbincn@qq.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/overlayfs/copy_up.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 65ac504595ba..a1ec45fc77d8 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -469,7 +469,6 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c) err = PTR_ERR(upper); if (!IS_ERR(upper)) { err = ovl_do_link(ovl_dentry_upper(c->dentry), udir, upper); - dput(upper); if (!err) { /* Restore timestamps on parent (best effort) */ @@ -477,6 +476,7 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c) ovl_dentry_set_upper_alias(c->dentry); ovl_dentry_update_reval(c->dentry, upper); } + dput(upper); } inode_unlock(udir); if (err) |