Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 072/153] ext4: fix use-after-iput when fscrypt contexts are inconsistent | Date | Fri, 10 Mar 2017 10:08:25 +0100 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Eric Biggers <ebiggers@google.com>
commit dd01b690f8f4b1e414f89e5a9a5326bf720d6652 upstream.
In the case where the child's encryption context was inconsistent with its parent directory, we were using inode->i_sb and inode->i_ino after the inode had already been iput(). Fix this by doing the iput() in the correct places.
Note: only ext4 had this bug, not f2fs and ubifs.
Fixes: d9cdc9033181 ("ext4 crypto: enforce context consistency") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/ext4/namei.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1616,13 +1616,15 @@ static struct dentry *ext4_lookup(struct !fscrypt_has_permitted_context(dir, inode)) { int nokey = ext4_encrypted_inode(inode) && !fscrypt_has_encryption_key(inode); - iput(inode); - if (nokey) + if (nokey) { + iput(inode); return ERR_PTR(-ENOKEY); + } ext4_warning(inode->i_sb, "Inconsistent encryption contexts: %lu/%lu", (unsigned long) dir->i_ino, (unsigned long) inode->i_ino); + iput(inode); return ERR_PTR(-EPERM); } }
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