From 57bc19ec472ab303209b2d96a59a619c5221594d Mon Sep 17 00:00:00 2001 From: Andrew Chant Date: Wed, 8 Feb 2017 15:33:48 -0800 Subject: [PATCH] sdcardfs: limit stacking depth Limit filesystem stacking to prevent stack overflow. Bug: 32761463 Change-Id: I8b1462b9c0d6c7f00cf110724ffb17e7f307c51e Signed-off-by: Andrew Chant --- fs/sdcardfs/main.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c index a6522286d7314..8b51a124298f4 100755 --- a/fs/sdcardfs/main.c +++ b/fs/sdcardfs/main.c @@ -223,6 +223,13 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name, atomic_inc(&lower_sb->s_active); sdcardfs_set_lower_super(sb, lower_sb); + sb->s_stack_depth = lower_sb->s_stack_depth + 1; + if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { + pr_err("sdcardfs: maximum fs stacking depth exceeded\n"); + err = -EINVAL; + goto out_sput; + } + /* inherit maxbytes from lower file system */ sb->s_maxbytes = lower_sb->s_maxbytes;