From: Bob Peterson rpeterso@redhat.com
[ Upstream commit 2c47c1be51fbded1f7baa2ceaed90f97932f79be ]
Before this patch, gfs2_create_inode had a use-after-free for the iopen glock in some error paths because it did this:
gfs2_glock_put(io_gl); fail_gunlock2: if (io_gl) clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);
In some cases, the io_gl was used for create and only had one reference, so the glock might be freed before the clear_bit(). This patch tries to straighten it out by only jumping to the error paths where iopen is properly set, and moving the gfs2_glock_put after the clear_bit.
Signed-off-by: Bob Peterson rpeterso@redhat.com Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/inode.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index d968b5c5df217..a52b8b0dceeb9 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -715,7 +715,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
error = gfs2_trans_begin(sdp, blocks, 0); if (error) - goto fail_gunlock2; + goto fail_free_inode;
if (blocks > 1) { ip->i_eattr = ip->i_no_addr + 1; @@ -726,7 +726,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
error = gfs2_glock_get(sdp, ip->i_no_addr, &gfs2_iopen_glops, CREATE, &io_gl); if (error) - goto fail_gunlock2; + goto fail_free_inode;
BUG_ON(test_and_set_bit(GLF_INODE_CREATING, &io_gl->gl_flags));
@@ -735,7 +735,6 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, goto fail_gunlock2;
glock_set_object(ip->i_iopen_gh.gh_gl, ip); - gfs2_glock_put(io_gl); gfs2_set_iop(inode); insert_inode_hash(inode);
@@ -768,6 +767,8 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
mark_inode_dirty(inode); d_instantiate(dentry, inode); + /* After instantiate, errors should result in evict which will destroy + * both inode and iopen glocks properly. */ if (file) { file->f_mode |= FMODE_CREATED; error = finish_open(file, dentry, gfs2_open_common); @@ -775,15 +776,15 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, gfs2_glock_dq_uninit(ghs); gfs2_glock_dq_uninit(ghs + 1); clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags); + gfs2_glock_put(io_gl); return error;
fail_gunlock3: glock_clear_object(io_gl, ip); gfs2_glock_dq_uninit(&ip->i_iopen_gh); - gfs2_glock_put(io_gl); fail_gunlock2: - if (io_gl) - clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags); + clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags); + gfs2_glock_put(io_gl); fail_free_inode: if (ip->i_gl) { glock_clear_object(ip->i_gl, ip);