| Message ID | 20221213081103.2182231-1-jun.nie@linaro.org (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
| Series | fscrypt: Fix null pointer when defer i_crypt_info | expand |
On Tue, Dec 13, 2022 at 04:11:03PM +0800, Jun Nie wrote: > syzbot report below bug[1]. Fix it with checking null pointer before > deferring i_crypt_info. > > [1] > general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] > CPU: 3 PID: 456 Comm: repro Not tainted 6.1.0+gc0daf896 #169 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 > RIP: 0010:fscrypt_limit_io_blocks+0xfa/0x2c0 > Call Trace: > <TASK> > ext4_iomap_begin+0x6c5/0x7e0 > ? asym_cpu_capacity_scan+0x6b0/0x6b0 > ? ext4_iomap_begin_report+0x6b0/0x6b0 > ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 > ? ext4_commit_super+0x3c1/0x560 > ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 > ? ext4_handle_error+0x3bf/0x6b0 > ? ext4_iomap_begin_report+0x6b0/0x6b0 > iomap_iter+0x538/0xc80 > iomap_bmap+0x1ed/0x2d0 > ? iomap_to_fiemap+0x220/0x220 > ? rwsem_down_read_slowpath+0xc00/0xc00 > ? __ext4_iget+0x19c/0x4370 > ext4_bmap+0x288/0x470 > ? mpage_prepare_extent_to_map+0xd80/0xd80 > bmap+0xb1/0x120 > jbd2_journal_init_inode+0x7d/0x3f0 > ? up_write+0x6c/0xb0 > ? jbd2_journal_init_dev+0x130/0x130 > ? register_shrinker+0x33/0x160 > ext4_fill_super+0xa467/0xc650 > ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 > ? ext4_reconfigure+0x2ad0/0x2ad0 > ? snprintf+0xbb/0xf0 > ? vsprintf+0x40/0x40 > ? up_write+0x6c/0xb0 > ? __sanitizer_cov_trace_cmp4+0x16/0x20 > ? set_blocksize+0x2f0/0x380 > get_tree_bdev+0x438/0x740 > ? get_tree_bdev+0x438/0x740 > ? ext4_reconfigure+0x2ad0/0x2ad0 > ext4_get_tree+0x1d/0x30 > vfs_get_tree+0x88/0x2e0 > path_mount+0x6ca/0x1ec0 > ? putname+0x110/0x150 > ? finish_automount+0x790/0x790 > ? putname+0x115/0x150 > __x64_sys_mount+0x2aa/0x340 > ? copy_mnt_ns+0xab0/0xab0 > ? __sanitizer_cov_trace_cmp4+0x16/0x20 > ? exit_to_user_mode_prepare+0x40/0x120 > do_syscall_64+0x35/0x80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > Fixes: 5fee36095cda ("fscrypt: add inline encryption support") > Reported-by: syzbot+ba9dac45bc76c490b7c3@syzkaller.appspotmail.com > Signed-off-by: Jun Nie <jun.nie@linaro.org> > --- > fs/crypto/inline_crypt.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c > index cea8b14007e6..fec859e83774 100644 > --- a/fs/crypto/inline_crypt.c > +++ b/fs/crypto/inline_crypt.c > @@ -232,7 +232,7 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb, > > bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode) > { > - return inode->i_crypt_info->ci_inlinecrypt; > + return inode->i_crypt_info && inode->i_crypt_info->ci_inlinecrypt; > } > EXPORT_SYMBOL_GPL(__fscrypt_inode_uses_inline_crypto); Thanks, but this has already been fixed upstream by commit 105c78e12468 ("ext4: don't allow journal inode to have encrypt flag"). Also, I don't think adding a NULL check to __fscrypt_inode_uses_inline_crypto() is a good idea because it is only meant to be called when the inode's encryption key has already been set up. Instead of making the function return a potentially-incorrect result, it was better to address the root cause of why it was being called at an inappropriate time in the first place. - Eric
Eric Biggers <ebiggers@kernel.org> 于2022年12月14日周三 02:54写道： > > On Tue, Dec 13, 2022 at 04:11:03PM +0800, Jun Nie wrote: > > syzbot report below bug[1]. Fix it with checking null pointer before > > deferring i_crypt_info. > > > > Thanks, but this has already been fixed upstream by commit 105c78e12468 > ("ext4: don't allow journal inode to have encrypt flag"). > > Also, I don't think adding a NULL check to __fscrypt_inode_uses_inline_crypto() > is a good idea because it is only meant to be called when the inode's encryption > key has already been set up. Instead of making the function return a > potentially-incorrect result, it was better to address the root cause of why it > was being called at an inappropriate time in the first place. > > - Eric Thanks for the information! Do you know what's the plan/schedule of back porting, such as linux-5.15.y branch? - Jun
On Wed, Dec 14, 2022 at 09:33:41AM +0800, Jun Nie wrote: > Eric Biggers <ebiggers@kernel.org> 于2022年12月14日周三 02:54写道： > > > > On Tue, Dec 13, 2022 at 04:11:03PM +0800, Jun Nie wrote: > > > syzbot report below bug[1]. Fix it with checking null pointer before > > > deferring i_crypt_info. > > > > > > > Thanks, but this has already been fixed upstream by commit 105c78e12468 > > ("ext4: don't allow journal inode to have encrypt flag"). > > > > Also, I don't think adding a NULL check to __fscrypt_inode_uses_inline_crypto() > > is a good idea because it is only meant to be called when the inode's encryption > > key has already been set up. Instead of making the function return a > > potentially-incorrect result, it was better to address the root cause of why it > > was being called at an inappropriate time in the first place. > > > > - Eric > > Thanks for the information! Do you know what's the plan/schedule of > back porting, > such as linux-5.15.y branch? > > - Jun The commit has 'Cc: stable@vger.kernel.org', and it is marked as fixing a commit in 5.9. So it will be backported to 5.10 LTS and later. It will take a little while for the stable maintainers to pick it up, though, since it just made it upstream yesterday. - Eric
diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index cea8b14007e6..fec859e83774 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -232,7 +232,7 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb, bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode) { - return inode->i_crypt_info->ci_inlinecrypt; + return inode->i_crypt_info && inode->i_crypt_info->ci_inlinecrypt; } EXPORT_SYMBOL_GPL(__fscrypt_inode_uses_inline_crypto);
syzbot report below bug[1]. Fix it with checking null pointer before deferring i_crypt_info. [1] general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 3 PID: 456 Comm: repro Not tainted 6.1.0+gc0daf896 #169 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:fscrypt_limit_io_blocks+0xfa/0x2c0 Call Trace: <TASK> ext4_iomap_begin+0x6c5/0x7e0 ? asym_cpu_capacity_scan+0x6b0/0x6b0 ? ext4_iomap_begin_report+0x6b0/0x6b0 ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 ? ext4_commit_super+0x3c1/0x560 ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 ? ext4_handle_error+0x3bf/0x6b0 ? ext4_iomap_begin_report+0x6b0/0x6b0 iomap_iter+0x538/0xc80 iomap_bmap+0x1ed/0x2d0 ? iomap_to_fiemap+0x220/0x220 ? rwsem_down_read_slowpath+0xc00/0xc00 ? __ext4_iget+0x19c/0x4370 ext4_bmap+0x288/0x470 ? mpage_prepare_extent_to_map+0xd80/0xd80 bmap+0xb1/0x120 jbd2_journal_init_inode+0x7d/0x3f0 ? up_write+0x6c/0xb0 ? jbd2_journal_init_dev+0x130/0x130 ? register_shrinker+0x33/0x160 ext4_fill_super+0xa467/0xc650 ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 ? ext4_reconfigure+0x2ad0/0x2ad0 ? snprintf+0xbb/0xf0 ? vsprintf+0x40/0x40 ? up_write+0x6c/0xb0 ? __sanitizer_cov_trace_cmp4+0x16/0x20 ? set_blocksize+0x2f0/0x380 get_tree_bdev+0x438/0x740 ? get_tree_bdev+0x438/0x740 ? ext4_reconfigure+0x2ad0/0x2ad0 ext4_get_tree+0x1d/0x30 vfs_get_tree+0x88/0x2e0 path_mount+0x6ca/0x1ec0 ? putname+0x110/0x150 ? finish_automount+0x790/0x790 ? putname+0x115/0x150 __x64_sys_mount+0x2aa/0x340 ? copy_mnt_ns+0xab0/0xab0 ? __sanitizer_cov_trace_cmp4+0x16/0x20 ? exit_to_user_mode_prepare+0x40/0x120 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: 5fee36095cda ("fscrypt: add inline encryption support") Reported-by: syzbot+ba9dac45bc76c490b7c3@syzkaller.appspotmail.com Signed-off-by: Jun Nie <jun.nie@linaro.org> --- fs/crypto/inline_crypt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)