| Message ID | 2481796.1742296819@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | afs: Fix afs_atcell_get_link() to check if ws_cell is unset first | expand |
On Tue, 18 Mar 2025 11:20:19 +0000, David Howells wrote: > Fix afs_atcell_get_link() to check if the workstation cell is unset before > doing the RCU pathwalk bit where we dereference that. > > Fixes: 823869e1e616 ("afs: Fix afs_atcell_get_link() to handle RCU pathwalk") > Reported-by: syzbot+76a6f18e3af82e84f264@syzkaller.appspotmail.com > Signed-off-by: David Howells <dhowells@redhat.com> > Tested-by: syzbot+76a6f18e3af82e84f264@syzkaller.appspotmail.com > cc: Marc Dionne <marc.dionne@auristor.com> > cc: linux-afs@lists.infradead.org > cc: linux-fsdevel@vger.kernel.org My fix already sent, it is much earlier than your patch. https://lore.kernel.org/all/tencent_8CA5671E3C533638973237484A0874917609@qq.com/ BR, Edward
On Tue, 18 Mar 2025 11:20:19 +0000, David Howells wrote: > Fix afs_atcell_get_link() to check if the workstation cell is unset before > doing the RCU pathwalk bit where we dereference that. > > Applied to the vfs.fixes branch of the vfs/vfs.git tree. Patches in the vfs.fixes branch should appear in linux-next soon. Please report any outstanding bugs that were missed during review in a new review to the original patch series allowing us to drop it. It's encouraged to provide Acked-bys and Reviewed-bys even though the patch has now been applied. If possible patch trailers will be updated. Note that commit hashes shown below are subject to change due to rebase, trailer updates or similar. If in doubt, please check the listed branch. tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git branch: vfs.fixes [1/1] afs: Fix afs_atcell_get_link() to check if ws_cell is unset first https://git.kernel.org/vfs/vfs/c/0307d16f3610
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c index 9732a1e17db3..691e0ae607a1 100644 --- a/fs/afs/dynroot.c +++ b/fs/afs/dynroot.c @@ -210,6 +210,9 @@ static const char *afs_atcell_get_link(struct dentry *dentry, struct inode *inod const char *name; bool dotted = vnode->fid.vnode == 3; + if (!rcu_access_pointer(net->ws_cell)) + return ERR_PTR(-ENOENT); + if (!dentry) { /* We're in RCU-pathwalk. */ cell = rcu_dereference(net->ws_cell); @@ -221,9 +224,6 @@ static const char *afs_atcell_get_link(struct dentry *dentry, struct inode *inod return name; } - if (!rcu_access_pointer(net->ws_cell)) - return ERR_PTR(-ENOENT); - down_read(&net->cells_lock); cell = rcu_dereference_protected(net->ws_cell, lockdep_is_held(&net->cells_lock));
Fix afs_atcell_get_link() to check if the workstation cell is unset before doing the RCU pathwalk bit where we dereference that. Fixes: 823869e1e616 ("afs: Fix afs_atcell_get_link() to handle RCU pathwalk") Reported-by: syzbot+76a6f18e3af82e84f264@syzkaller.appspotmail.com Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: syzbot+76a6f18e3af82e84f264@syzkaller.appspotmail.com cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org --- fs/afs/dynroot.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)