| Message ID | 20240601113749.473058-1-lizhi.xu@windriver.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | [V5] ext4: check hash version and filesystem casefolded consistent | expand |
Lizhi Xu <lizhi.xu@windriver.com> writes: > When mounting the ext4 filesystem, if the hash version and casefolded are not > consistent, exit the mounting. > > Reported-by: syzbot+340581ba9dceb7e06fb3@syzkaller.appspotmail.com > Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com> > --- > fs/ext4/super.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index c682fb927b64..0ad326504c50 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -5262,6 +5262,11 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) > goto failed_mount; > > ext4_hash_info_init(sb); > + if (es->s_def_hash_version == DX_HASH_SIPHASH && > + !ext4_has_feature_casefold(sb)) { Can we ever have DX_HASH_SIPHASH set up in the super block? I thought it was used solely for directories where ext4_hash_in_dirent(inode) is true. If this is only for the case of a superblock corruption, perhaps we should always reject the mount, whether casefold is enabled or not?
On Mon, 03 Jun 2024 10:50:51 -0400, Gabriel Krisman Bertazi wrote: > > When mounting the ext4 filesystem, if the hash version and casefolded are not > > consistent, exit the mounting. > > > > Reported-by: syzbot+340581ba9dceb7e06fb3@syzkaller.appspotmail.com > > Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com> > > --- > > fs/ext4/super.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > > index c682fb927b64..0ad326504c50 100644 > > --- a/fs/ext4/super.c > > +++ b/fs/ext4/super.c > > @@ -5262,6 +5262,11 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) > > goto failed_mount; > > > > ext4_hash_info_init(sb); > > + if (es->s_def_hash_version == DX_HASH_SIPHASH && > > + !ext4_has_feature_casefold(sb)) { > > Can we ever have DX_HASH_SIPHASH set up in the super block? I thought > it was used solely for directories where ext4_hash_in_dirent(inode) is > true. The value of s'def_hash_version is obtained by reading the super block from the buffer cache of the block device in ext4_load_super(). > > If this is only for the case of a superblock corruption, perhaps we > should always reject the mount, whether casefold is enabled or not? Based on the existing information, it cannot be confirmed whether the superblock is corrupt, but one thing is clear: if the default hash version of the superblock is set to DX_HASH_SIPHASH, but the casefold feature is not set at the same time, it is definitely an error. Lizhi
Lizhi Xu <lizhi.xu@windriver.com> writes: > On Mon, 03 Jun 2024 10:50:51 -0400, Gabriel Krisman Bertazi wrote: >> > When mounting the ext4 filesystem, if the hash version and casefolded are not >> > consistent, exit the mounting. >> > >> > Reported-by: syzbot+340581ba9dceb7e06fb3@syzkaller.appspotmail.com >> > Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com> >> > --- >> > fs/ext4/super.c | 5 +++++ >> > 1 file changed, 5 insertions(+) >> > >> > diff --git a/fs/ext4/super.c b/fs/ext4/super.c >> > index c682fb927b64..0ad326504c50 100644 >> > --- a/fs/ext4/super.c >> > +++ b/fs/ext4/super.c >> > @@ -5262,6 +5262,11 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) >> > goto failed_mount; >> > >> > ext4_hash_info_init(sb); >> > + if (es->s_def_hash_version == DX_HASH_SIPHASH && >> > + !ext4_has_feature_casefold(sb)) { >> >> Can we ever have DX_HASH_SIPHASH set up in the super block? I thought >> it was used solely for directories where ext4_hash_in_dirent(inode) is >> true. > The value of s'def_hash_version is obtained by reading the super block from the > buffer cache of the block device in ext4_load_super(). Yes, I know. My point is whether this check should just be: if (es->s_def_hash_version == DX_HASH_SIPHASH) goto failed_mount; Since, IIUC, DX_HASH_SIPHASH is done per-directory and not written to the sb. >> If this is only for the case of a superblock corruption, perhaps we >> should always reject the mount, whether casefold is enabled or not? > Based on the existing information, it cannot be confirmed whether the superblock > is corrupt, but one thing is clear: if the default hash version of the superblock > is set to DX_HASH_SIPHASH, but the casefold feature is not set at the same time, > it is definitely an error.
On Tue, 04 Jun 2024 15:06:32 -0400, Gabriel Krisman Bertazi wrote: > >> > When mounting the ext4 filesystem, if the hash version and casefolded are not > >> > consistent, exit the mounting. > >> > > >> > Reported-by: syzbot+340581ba9dceb7e06fb3@syzkaller.appspotmail.com > >> > Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com> > >> > --- > >> > fs/ext4/super.c | 5 +++++ > >> > 1 file changed, 5 insertions(+) > >> > > >> > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > >> > index c682fb927b64..0ad326504c50 100644 > >> > --- a/fs/ext4/super.c > >> > +++ b/fs/ext4/super.c > >> > @@ -5262,6 +5262,11 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) > >> > goto failed_mount; > >> > > >> > ext4_hash_info_init(sb); > >> > + if (es->s_def_hash_version == DX_HASH_SIPHASH && > >> > + !ext4_has_feature_casefold(sb)) { > >> > >> Can we ever have DX_HASH_SIPHASH set up in the super block? I thought > >> it was used solely for directories where ext4_hash_in_dirent(inode) is > >> true. > > The value of s'def_hash_version is obtained by reading the super block from the > > buffer cache of the block device in ext4_load_super(). > > Yes, I know. My point is whether this check should just be: Based on the existing information, it cannot be confirmed that it is incorrect to separately determine the value of s_def_hash_version as DX_HASH_SIPHASH. Additionally, I have come up with a better solution, and I will issue the next fixed version in a while. > > if (es->s_def_hash_version == DX_HASH_SIPHASH) > goto failed_mount; > > Since, IIUC, DX_HASH_SIPHASH is done per-directory and not written to > the sb. > > >> If this is only for the case of a superblock corruption, perhaps we > >> should always reject the mount, whether casefold is enabled or not? > > Based on the existing information, it cannot be confirmed whether the superblock > > is corrupt, but one thing is clear: if the default hash version of the superblock > > is set to DX_HASH_SIPHASH, but the casefold feature is not set at the same time, > > it is definitely an error. Lizhi
On Tue, Jun 04, 2024 at 03:06:32PM -0400, Gabriel Krisman Bertazi wrote: > Lizhi Xu <lizhi.xu@windriver.com> writes: > > > On Mon, 03 Jun 2024 10:50:51 -0400, Gabriel Krisman Bertazi wrote: > >> > When mounting the ext4 filesystem, if the hash version and casefolded are not > >> > consistent, exit the mounting. > >> > > >> > Reported-by: syzbot+340581ba9dceb7e06fb3@syzkaller.appspotmail.com > >> > Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com> > >> > --- > >> > fs/ext4/super.c | 5 +++++ > >> > 1 file changed, 5 insertions(+) > >> > > >> > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > >> > index c682fb927b64..0ad326504c50 100644 > >> > --- a/fs/ext4/super.c > >> > +++ b/fs/ext4/super.c > >> > @@ -5262,6 +5262,11 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) > >> > goto failed_mount; > >> > > >> > ext4_hash_info_init(sb); > >> > + if (es->s_def_hash_version == DX_HASH_SIPHASH && > >> > + !ext4_has_feature_casefold(sb)) { > >> > >> Can we ever have DX_HASH_SIPHASH set up in the super block? I thought > >> it was used solely for directories where ext4_hash_in_dirent(inode) is > >> true. > > The value of s'def_hash_version is obtained by reading the super block from the > > buffer cache of the block device in ext4_load_super(). > > Yes, I know. My point is whether this check should just be: > > if (es->s_def_hash_version == DX_HASH_SIPHASH) > goto failed_mount; > > Since, IIUC, DX_HASH_SIPHASH is done per-directory and not written to > the sb. > That seems right to me. SipHash can never be the default because it's only used on directories that are both encrypted and casefolded. - Eric
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index c682fb927b64..0ad326504c50 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5262,6 +5262,11 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) goto failed_mount; ext4_hash_info_init(sb); + if (es->s_def_hash_version == DX_HASH_SIPHASH && + !ext4_has_feature_casefold(sb)) { + err = -EINVAL; + goto failed_mount; + } err = ext4_handle_clustersize(sb); if (err)
When mounting the ext4 filesystem, if the hash version and casefolded are not consistent, exit the mounting. Reported-by: syzbot+340581ba9dceb7e06fb3@syzkaller.appspotmail.com Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com> --- fs/ext4/super.c | 5 +++++ 1 file changed, 5 insertions(+)