Messages in this thread Patch in this message | | | From | Colin King <> | Subject | [PATCH][next] ovl: fix null pointer dereference on null stack pointer on error return | Date | Wed, 3 Jun 2020 16:45:59 +0100 |
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From: Colin Ian King <colin.king@canonical.com>
There are two error return paths where the call to path_put is dereferencing the null pointer 'stack'. Fix this by avoiding the error exit path via label 'out_err' that will lead to the path_put calls and instead just return the error code directly.
Addresses-Coverity: ("Dereference after null check)" Fixes: 4155c10a0309 ("ovl: clean up getting lower layers") Signed-off-by: Colin Ian King <colin.king@canonical.com> --- fs/overlayfs/super.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 1094836f7e31..4be1b041b32c 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -1594,20 +1594,18 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, unsigned int i; struct ovl_entry *oe; - err = -EINVAL; if (!ofs->config.upperdir && numlower == 1) { pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); - goto out_err; + return ERR_PTR(-EINVAL); } else if (!ofs->config.upperdir && ofs->config.nfs_export && ofs->config.redirect_follow) { pr_warn("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); ofs->config.nfs_export = false; } - err = -ENOMEM; stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); if (!stack) - goto out_err; + return ERR_PTR(-ENOMEM); err = -EINVAL; for (i = 0; i < numlower; i++) { -- 2.25.1
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