From: Filipe Manana <fdmanana(a)suse.com>
mainline inclusion
from mainline-v6.13-rc5
commit 44f52bbe96dfdbe4aca3818a2534520082a07040
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBG2PK
CVE: CVE-2024-56759
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?…
--------------------------------
When a COWing a tree block, at btrfs_cow_block(), and we have the
tracepoint trace_btrfs_cow_block() enabled and preemption is also enabled
(CONFIG_PREEMPT=y), we can trigger a use-after-free in the COWed extent
buffer while inside the tracepoint code. This is because in some paths
that call btrfs_cow_block(), such as btrfs_search_slot(), we are holding
the last reference on the extent buffer @buf so btrfs_force_cow_block()
drops the last reference on the @buf extent buffer when it calls
free_extent_buffer_stale(buf), which schedules the release of the extent
buffer with RCU. This means that if we are on a kernel with preemption,
the current task may be preempted before calling trace_btrfs_cow_block()
and the extent buffer already released by the time trace_btrfs_cow_block()
is called, resulting in a use-after-free.
Fix this by moving the trace_btrfs_cow_block() from btrfs_cow_block() to
btrfs_force_cow_block() before the COWed extent buffer is freed.
This also has a side effect of invoking the tracepoint in the tree defrag
code, at defrag.c:btrfs_realloc_node(), since btrfs_force_cow_block() is
called there, but this is fine and it was actually missing there.
Reported-by: syzbot+8517da8635307182c8a5(a)syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/6759a9b9.050a0220.1ac542.000d.GAE@googl…
CC: stable(a)vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu(a)suse.com>
Signed-off-by: Filipe Manana <fdmanana(a)suse.com>
Signed-off-by: David Sterba <dsterba(a)suse.com>
Conflicts:
fs/btrfs/ctree.c
[__btrfs_cow_block did not rename to btrfs_force_cow_block yet.]
Signed-off-by: Yifan Qiao <qiaoyifan4(a)huawei.com>
---
fs/btrfs/ctree.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 2eb4e03080ac..ddcc22384e36 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -648,6 +648,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
btrfs_free_tree_block(trans, btrfs_root_id(root), buf,
parent_start, last_ref);
}
+
+ trace_btrfs_cow_block(root, buf, cow);
if (unlock_orig)
btrfs_tree_unlock(buf);
free_extent_buffer_stale(buf);
@@ -699,7 +701,6 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 search_start;
- int ret;
if (unlikely(test_bit(BTRFS_ROOT_DELETING, &root->state))) {
btrfs_abort_transaction(trans, -EUCLEAN);
@@ -740,12 +741,8 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
* Also We don't care about the error, as it's handled internally.
*/
btrfs_qgroup_trace_subtree_after_cow(trans, root, buf);
- ret = __btrfs_cow_block(trans, root, buf, parent,
+ return __btrfs_cow_block(trans, root, buf, parent,
parent_slot, cow_ret, search_start, 0, nest);
-
- trace_btrfs_cow_block(root, buf, *cow_ret);
-
- return ret;
}
ALLOW_ERROR_INJECTION(btrfs_cow_block, ERRNO);
--
2.39.2
From: Filipe Manana <fdmanana(a)suse.com>
mainline inclusion
from mainline-v6.13-rc5
commit 44f52bbe96dfdbe4aca3818a2534520082a07040
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBG2PK
CVE: CVE-2024-56759
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?…
--------------------------------
When a COWing a tree block, at btrfs_cow_block(), and we have the
tracepoint trace_btrfs_cow_block() enabled and preemption is also enabled
(CONFIG_PREEMPT=y), we can trigger a use-after-free in the COWed extent
buffer while inside the tracepoint code. This is because in some paths
that call btrfs_cow_block(), such as btrfs_search_slot(), we are holding
the last reference on the extent buffer @buf so btrfs_force_cow_block()
drops the last reference on the @buf extent buffer when it calls
free_extent_buffer_stale(buf), which schedules the release of the extent
buffer with RCU. This means that if we are on a kernel with preemption,
the current task may be preempted before calling trace_btrfs_cow_block()
and the extent buffer already released by the time trace_btrfs_cow_block()
is called, resulting in a use-after-free.
Fix this by moving the trace_btrfs_cow_block() from btrfs_cow_block() to
btrfs_force_cow_block() before the COWed extent buffer is freed.
This also has a side effect of invoking the tracepoint in the tree defrag
code, at defrag.c:btrfs_realloc_node(), since btrfs_force_cow_block() is
called there, but this is fine and it was actually missing there.
Reported-by: syzbot+8517da8635307182c8a5(a)syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/6759a9b9.050a0220.1ac542.000d.GAE@googl…
CC: stable(a)vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu(a)suse.com>
Signed-off-by: Filipe Manana <fdmanana(a)suse.com>
Signed-off-by: David Sterba <dsterba(a)suse.com>
Conflicts:
fs/btrfs/ctree.c
[__btrfs_cow_block did not rename to btrfs_force_cow_block yet.]
Signed-off-by: Yifan Qiao <qiaoyifan4(a)huawei.com>
---
fs/btrfs/ctree.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 55896280b2dd..21b5c0f12beb 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1127,6 +1127,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
btrfs_free_tree_block(trans, root, buf, parent_start,
last_ref);
}
+
+ trace_btrfs_cow_block(root, buf, cow);
if (unlock_orig)
btrfs_tree_unlock(buf);
free_extent_buffer_stale(buf);
@@ -1493,7 +1495,6 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 search_start;
- int ret;
if (test_bit(BTRFS_ROOT_DELETING, &root->state))
btrfs_err(fs_info,
@@ -1527,12 +1528,8 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
* Also We don't care about the error, as it's handled internally.
*/
btrfs_qgroup_trace_subtree_after_cow(trans, root, buf);
- ret = __btrfs_cow_block(trans, root, buf, parent,
+ return __btrfs_cow_block(trans, root, buf, parent,
parent_slot, cow_ret, search_start, 0, nest);
-
- trace_btrfs_cow_block(root, buf, *cow_ret);
-
- return ret;
}
/*
--
2.39.2
From: Filipe Manana <fdmanana(a)suse.com>
mainline inclusion
from mainline-v6.13-rc5
commit 44f52bbe96dfdbe4aca3818a2534520082a07040
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBG2PK
CVE: CVE-2024-56759
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?…
--------------------------------
When a COWing a tree block, at btrfs_cow_block(), and we have the
tracepoint trace_btrfs_cow_block() enabled and preemption is also enabled
(CONFIG_PREEMPT=y), we can trigger a use-after-free in the COWed extent
buffer while inside the tracepoint code. This is because in some paths
that call btrfs_cow_block(), such as btrfs_search_slot(), we are holding
the last reference on the extent buffer @buf so btrfs_force_cow_block()
drops the last reference on the @buf extent buffer when it calls
free_extent_buffer_stale(buf), which schedules the release of the extent
buffer with RCU. This means that if we are on a kernel with preemption,
the current task may be preempted before calling trace_btrfs_cow_block()
and the extent buffer already released by the time trace_btrfs_cow_block()
is called, resulting in a use-after-free.
Fix this by moving the trace_btrfs_cow_block() from btrfs_cow_block() to
btrfs_force_cow_block() before the COWed extent buffer is freed.
This also has a side effect of invoking the tracepoint in the tree defrag
code, at defrag.c:btrfs_realloc_node(), since btrfs_force_cow_block() is
called there, but this is fine and it was actually missing there.
Reported-by: syzbot+8517da8635307182c8a5(a)syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/6759a9b9.050a0220.1ac542.000d.GAE@googl…
CC: stable(a)vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu(a)suse.com>
Signed-off-by: Filipe Manana <fdmanana(a)suse.com>
Signed-off-by: David Sterba <dsterba(a)suse.com>
Conflicts:
fs/btrfs/ctree.c
[__btrfs_cow_block did not rename to btrfs_force_cow_block yet.]
Signed-off-by: Yifan Qiao <qiaoyifan4(a)huawei.com>
---
fs/btrfs/ctree.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f88c443cffea..ebc4fff273a6 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1127,6 +1127,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
btrfs_free_tree_block(trans, root, buf, parent_start,
last_ref);
}
+
+ trace_btrfs_cow_block(root, buf, cow);
if (unlock_orig)
btrfs_tree_unlock(buf);
free_extent_buffer_stale(buf);
@@ -1493,7 +1495,6 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 search_start;
- int ret;
if (test_bit(BTRFS_ROOT_DELETING, &root->state))
btrfs_err(fs_info,
@@ -1527,12 +1528,8 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
* Also We don't care about the error, as it's handled internally.
*/
btrfs_qgroup_trace_subtree_after_cow(trans, root, buf);
- ret = __btrfs_cow_block(trans, root, buf, parent,
+ return __btrfs_cow_block(trans, root, buf, parent,
parent_slot, cow_ret, search_start, 0, nest);
-
- trace_btrfs_cow_block(root, buf, *cow_ret);
-
- return ret;
}
/*
--
2.39.2