From 6456ca6520ab6c9aec589b4640169cd6da378c68 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Tue, 3 Sep 2019 01:43:17 -0400 Subject: ext4: fix kernel oops caused by spurious casefold flag If an directory has the a casefold flag set without the casefold feature set, s_encoding will not be initialized, and this will cause the kernel to dereference a NULL pointer. In addition to adding checks to avoid these kernel oops, attempts to load inodes with the casefold flag when the casefold feature is not enable will cause the file system to be declared corrupted. Signed-off-by: Theodore Ts'o --- fs/ext4/dir.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'fs/ext4/dir.c') diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index 86054f31fe4d..9fdd2b269d61 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -668,14 +668,15 @@ static int ext4_d_compare(const struct dentry *dentry, unsigned int len, const char *str, const struct qstr *name) { struct qstr qstr = {.name = str, .len = len }; + struct inode *inode = dentry->d_parent->d_inode; - if (!IS_CASEFOLDED(dentry->d_parent->d_inode)) { + if (!IS_CASEFOLDED(inode) || !EXT4_SB(inode->i_sb)->s_encoding) { if (len != name->len) return -1; return memcmp(str, name->name, len); } - return ext4_ci_compare(dentry->d_parent->d_inode, name, &qstr, false); + return ext4_ci_compare(inode, name, &qstr, false); } static int ext4_d_hash(const struct dentry *dentry, struct qstr *str) @@ -685,7 +686,7 @@ static int ext4_d_hash(const struct dentry *dentry, struct qstr *str) unsigned char *norm; int len, ret = 0; - if (!IS_CASEFOLDED(dentry->d_inode)) + if (!IS_CASEFOLDED(dentry->d_inode) || !um) return 0; norm = kmalloc(PATH_MAX, GFP_ATOMIC); -- cgit v1.2.3