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authorDavid Howells <dhowells@redhat.com>2020-01-14 16:16:25 +0000
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-14 09:40:06 -0800
commit40a708bd622b78582ae3d280de29b09b50bd04c0 (patch)
tree2a359efe3c25cac13f68e7847925888fc160bc21 /fs
parent8379bb84be757d5df2d818509faec5d66adb861d (diff)
afs: Fix use-after-loss-of-ref
afs_lookup() has a tracepoint to indicate the outcome of d_splice_alias(), passing it the inode to retrieve the fid from. However, the function gave up its ref on that inode when it called d_splice_alias(), which may have failed and dropped the inode. Fix this by caching the fid. Fixes: 80548b03991f ("afs: Add more tracepoints") Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/afs/dir.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 497f979018c2..813db1708494 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -908,6 +908,7 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct afs_vnode *dvnode = AFS_FS_I(dir);
+ struct afs_fid fid = {};
struct inode *inode;
struct dentry *d;
struct key *key;
@@ -957,15 +958,16 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
dentry->d_fsdata =
(void *)(unsigned long)dvnode->status.data_version;
}
+
+ if (!IS_ERR_OR_NULL(inode))
+ fid = AFS_FS_I(inode)->fid;
+
d = d_splice_alias(inode, dentry);
if (!IS_ERR_OR_NULL(d)) {
d->d_fsdata = dentry->d_fsdata;
- trace_afs_lookup(dvnode, &d->d_name,
- inode ? AFS_FS_I(inode) : NULL);
+ trace_afs_lookup(dvnode, &d->d_name, &fid);
} else {
- trace_afs_lookup(dvnode, &dentry->d_name,
- IS_ERR_OR_NULL(inode) ? NULL
- : AFS_FS_I(inode));
+ trace_afs_lookup(dvnode, &dentry->d_name, &fid);
}
return d;
}

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