It's possible to specify a non-zero s_want_extra_isize via debugging
option, and this can cause bad things(tm) to happen when using a file
system with an inode size of 128 bytes.
Add better checking when the file system is mounted, as well as when
we are actually doing the trying to do the inode expansion.
Reported-by: syzbot+f8d6f8386ceacdbfff57@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
---
fs/ext4/inode.c | 14 ++++++++++++++
fs/ext4/super.c | 21 ++++++++++++---------
2 files changed, 26 insertions(+), 9 deletions(-)
@@ -5569,8 +5569,22 @@ static int __ext4_expand_extra_isize(struct inode *inode,{structext4_inode*raw_inode;structext4_xattr_ibody_header*header;+unsignedintinode_size=EXT4_INODE_SIZE(inode->i_sb);interror;+/* this was checked at iget time, but double check for good measure */+if((EXT4_GOOD_OLD_INODE_SIZE+ei->i_extra_isize>inode_size)||+(ei->i_extra_isize&3)){+EXT4_ERROR_INODE(inode,"bad extra_isize %u (inode size %u)",+ei->i_extra_isize,+EXT4_INODE_SIZE(inode->i_sb));+return-EFSCORRUPTED;+}+if((new_extra_isize<ei->i_extra_size)||+(new_extra_isize<4)||+(new_extra_size>inode_size-EXT4_GOOD_OLD_INODE_SIZE))+retun-EINVAL;/* Should never happen */+raw_inode=ext4_raw_inode(iloc);header=IHDR(inode,raw_inode);
@@ -3545,12 +3545,15 @@ static void ext4_clamp_want_extra_isize(struct super_block *sb){structext4_sb_info*sbi=EXT4_SB(sb);structext4_super_block*es=sbi->s_es;+unsigneddef_extra_isize=sizeof(structext4_inode)-+EXT4_GOOD_OLD_INODE_SIZE;-/* determine the minimum size of new large inodes, if present */-if(sbi->s_inode_size>EXT4_GOOD_OLD_INODE_SIZE&&-sbi->s_want_extra_isize==0){-sbi->s_want_extra_isize=sizeof(structext4_inode)--EXT4_GOOD_OLD_INODE_SIZE;+if(sbi->s_inode_size==EXT4_GOOD_OLD_INODE_SIZE){+sbi->s_want_extra_isize=0;+return;+}+if(sbi->s_want_extra_isize<4){+sbi->s_want_extra_isize=def_extra_isize;if(ext4_has_feature_extra_isize(sb)){if(sbi->s_want_extra_isize<le16_to_cpu(es->s_want_extra_isize))
@@ -3563,10 +3566,10 @@ static void ext4_clamp_want_extra_isize(struct super_block *sb)}}/* Check if enough inode space is available */-if(EXT4_GOOD_OLD_INODE_SIZE+sbi->s_want_extra_isize>-sbi->s_inode_size){-sbi->s_want_extra_isize=sizeof(structext4_inode)--EXT4_GOOD_OLD_INODE_SIZE;+if((sbi->s_want_extra_isize>sbi->s_inode_size)||+(EXT4_GOOD_OLD_INODE_SIZE+sbi->s_want_extra_isize>+sbi->s_inode_size)){+sbi->s_want_extra_isize=def_extra_isize;ext4_msg(sb,KERN_INFO,"required extra inode space not available");}
From: kbuild test robot <hidden> Date: 2019-11-10 10:13:47
Hi Theodore,
I love your patch! Perhaps something to improve:
[auto build test WARNING on ext4/dev]
[also build test WARNING on v5.4-rc6 next-20191108]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Theodore-Ts-o/ext4-add-more-paranoia-checking-in-ext4_expand_extra_isize-handling/20191110-005324
base: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev
config: i386-randconfig-d003-201945 (attached as .config)
compiler: gcc-7 (Debian 7.4.0-14) 7.4.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <redacted>
All warnings (new ones prefixed by >>):
In file included from include/linux/export.h:44:0,
from include/linux/linkage.h:7,
from include/linux/fs.h:5,
from fs//ext4/inode.c:22:
fs//ext4/inode.c: In function '__ext4_expand_extra_isize':
fs//ext4/inode.c:5576:34: error: 'ei' undeclared (first use in this function)
if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
^
include/linux/compiler.h:58:52: note: in definition of macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
quoted
fs//ext4/inode.c:5576:2: note: in expansion of macro 'if'
if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
^~
fs//ext4/inode.c:5576:34: note: each undeclared identifier is reported only once for each function it appears in
if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
^
include/linux/compiler.h:58:52: note: in definition of macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
quoted
fs//ext4/inode.c:5576:2: note: in expansion of macro 'if'
if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
^~
fs//ext4/inode.c:5585:7: error: 'new_extra_size' undeclared (first use in this function); did you mean 'new_extra_isize'?
(new_extra_size > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
^
include/linux/compiler.h:58:52: note: in definition of macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
fs//ext4/inode.c:5583:2: note: in expansion of macro 'if'
if ((new_extra_isize < ei->i_extra_size) ||
^~
fs//ext4/inode.c:5586:3: error: 'retun' undeclared (first use in this function); did you mean 'semun'?
retun -EINVAL; /* Should never happen */
^~~~~
semun
vim +/if +5576 fs//ext4/inode.c
5564
5565 static int __ext4_expand_extra_isize(struct inode *inode,
5566 unsigned int new_extra_isize,
5567 struct ext4_iloc *iloc,
5568 handle_t *handle, int *no_expand)
5569 {
5570 struct ext4_inode *raw_inode;
5571 struct ext4_xattr_ibody_header *header;
5572 unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
5573 int error;
5574
5575 /* this was checked at iget time, but double check for good measure */
5576 if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
From: "Theodore Y. Ts'o" <tytso@mit.edu> Date: 2019-11-10 12:15:32
I hadn't gotten around to resending the patch. The original version
had a number of last-minute typos that had crept in...
- Ted
From a67ad537964d10f94a4b990c084365e75316cde8 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 7 Nov 2019 21:43:41 -0500
Subject: [PATCH] ext4: add more paranoia checking in ext4_expand_extra_isize
handling
It's possible to specify a non-zero s_want_extra_isize via debugging
option, and this can cause bad things(tm) to happen when using a file
system with an inode size of 128 bytes.
Add better checking when the file system is mounted, as well as when
we are actually doing the trying to do the inode expansion.
Reported-by: syzbot+f8d6f8386ceacdbfff57@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
---
fs/ext4/inode.c | 15 +++++++++++++++
fs/ext4/super.c | 21 ++++++++++++---------
2 files changed, 27 insertions(+), 9 deletions(-)
@@ -5569,8 +5569,23 @@ static int __ext4_expand_extra_isize(struct inode *inode,{structext4_inode*raw_inode;structext4_xattr_ibody_header*header;+unsignedintinode_size=EXT4_INODE_SIZE(inode->i_sb);+structext4_inode_info*ei=EXT4_I(inode);interror;+/* this was checked at iget time, but double check for good measure */+if((EXT4_GOOD_OLD_INODE_SIZE+ei->i_extra_isize>inode_size)||+(ei->i_extra_isize&3)){+EXT4_ERROR_INODE(inode,"bad extra_isize %u (inode size %u)",+ei->i_extra_isize,+EXT4_INODE_SIZE(inode->i_sb));+return-EFSCORRUPTED;+}+if((new_extra_isize<ei->i_extra_isize)||+(new_extra_isize<4)||+(new_extra_isize>inode_size-EXT4_GOOD_OLD_INODE_SIZE))+return-EINVAL;/* Should never happen */+raw_inode=ext4_raw_inode(iloc);header=IHDR(inode,raw_inode);
@@ -3545,12 +3545,15 @@ static void ext4_clamp_want_extra_isize(struct super_block *sb){structext4_sb_info*sbi=EXT4_SB(sb);structext4_super_block*es=sbi->s_es;+unsigneddef_extra_isize=sizeof(structext4_inode)-+EXT4_GOOD_OLD_INODE_SIZE;-/* determine the minimum size of new large inodes, if present */-if(sbi->s_inode_size>EXT4_GOOD_OLD_INODE_SIZE&&-sbi->s_want_extra_isize==0){-sbi->s_want_extra_isize=sizeof(structext4_inode)--EXT4_GOOD_OLD_INODE_SIZE;+if(sbi->s_inode_size==EXT4_GOOD_OLD_INODE_SIZE){+sbi->s_want_extra_isize=0;+return;+}+if(sbi->s_want_extra_isize<4){+sbi->s_want_extra_isize=def_extra_isize;if(ext4_has_feature_extra_isize(sb)){if(sbi->s_want_extra_isize<le16_to_cpu(es->s_want_extra_isize))
@@ -3563,10 +3566,10 @@ static void ext4_clamp_want_extra_isize(struct super_block *sb)}}/* Check if enough inode space is available */-if(EXT4_GOOD_OLD_INODE_SIZE+sbi->s_want_extra_isize>-sbi->s_inode_size){-sbi->s_want_extra_isize=sizeof(structext4_inode)--EXT4_GOOD_OLD_INODE_SIZE;+if((sbi->s_want_extra_isize>sbi->s_inode_size)||+(EXT4_GOOD_OLD_INODE_SIZE+sbi->s_want_extra_isize>+sbi->s_inode_size)){+sbi->s_want_extra_isize=def_extra_isize;ext4_msg(sb,KERN_INFO,"required extra inode space not available");}
From: Eric Biggers <ebiggers@kernel.org> Date: 2019-11-19 02:15:29
On Sun, Nov 10, 2019 at 07:15:10AM -0500, Theodore Y. Ts'o wrote:
I hadn't gotten around to resending the patch. The original version
had a number of last-minute typos that had crept in...
- Ted
From a67ad537964d10f94a4b990c084365e75316cde8 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 7 Nov 2019 21:43:41 -0500
Subject: [PATCH] ext4: add more paranoia checking in ext4_expand_extra_isize
handling
It's possible to specify a non-zero s_want_extra_isize via debugging
option, and this can cause bad things(tm) to happen when using a file
system with an inode size of 128 bytes.
Add better checking when the file system is mounted, as well as when
we are actually doing the trying to do the inode expansion.
Reported-by: syzbot+f8d6f8386ceacdbfff57@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Yes, it appears to be the same issue. Thanks for pointing this out!
- Ted
There's actually a third that looks very similar too:
"KASAN: use-after-free Write in __ext4_expand_extra_isize (2)"
https://lkml.kernel.org/linux-ext4/0000000000000d74c7059564e17f@google.com/
If these are all fixed by this patch, you can use:
Reported-by: syzbot+f8d6f8386ceacdbfff57@syzkaller.appspotmail.com
Reported-by: syzbot+33d7ea72e47de3bdf4e1@syzkaller.appspotmail.com
Reported-by: syzbot+44b6763edfc17144296f@syzkaller.appspotmail.com