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[PATCH openEuler-22.03-LTS-SP1] ext4: fix double brelse() the buffer of the extents path
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v5.10.227 commit b6c29c8f3d7cb67b505f3b2f6c242d52298d1f2e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYR8Z CVE: CVE-2024-49882 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit dcaa6c31134c0f515600111c38ed7750003e1b9c upstream. In ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been released, otherwise it may be released twice. An example of what triggers this is as follows: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path->p_depth == 0 ext4_split_extent // 1. do split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&neh->eh_depth, 1) | ext4_find_extent | // return -ENOMEM |// get error and try zeroout |path = ext4_find_extent | path->p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path->p_depth = 0 | brelse(path[1].p_bh) ---> not set to NULL here |// zeroout success // 2. update path ext4_find_extent // 3. do split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&neh->eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path->p_depth = 1 read_extent_tree_block ---> return err // path[1].p_bh is still the old value ext4_free_ext_path ext4_ext_drop_refs // path->p_depth == 1 brelse(path[1].p_bh) ---> brelse a buffer twice Finally got the following WARRNING when removing the buffer from lru: ============================================ VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Call Trace: <TASK> __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================ Fixes: ecb94f5fdf4b ("ext4: collapse a single extent tree block into the inode if possible") Cc: stable(a)kernel.org Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Tested-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Link: https://patch.msgid.link/20240822023545.1994557-9-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 04b0346599c5..d7be8b8ed3da 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1878,6 +1878,7 @@ static void ext4_ext_try_to_merge_up(handle_t *handle, path[0].p_hdr->eh_max = cpu_to_le16(max_root); brelse(path[1].p_bh); + path[1].p_bh = NULL; ext4_free_blocks(handle, inode, NULL, blk, 1, EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); } -- 2.46.1

2 1

[PATCH OLK-5.10] ext4: fix double brelse() the buffer of the extents path
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v5.10.227 commit b6c29c8f3d7cb67b505f3b2f6c242d52298d1f2e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYR8Z CVE: CVE-2024-49882 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit dcaa6c31134c0f515600111c38ed7750003e1b9c upstream. In ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been released, otherwise it may be released twice. An example of what triggers this is as follows: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path->p_depth == 0 ext4_split_extent // 1. do split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&neh->eh_depth, 1) | ext4_find_extent | // return -ENOMEM |// get error and try zeroout |path = ext4_find_extent | path->p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path->p_depth = 0 | brelse(path[1].p_bh) ---> not set to NULL here |// zeroout success // 2. update path ext4_find_extent // 3. do split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&neh->eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path->p_depth = 1 read_extent_tree_block ---> return err // path[1].p_bh is still the old value ext4_free_ext_path ext4_ext_drop_refs // path->p_depth == 1 brelse(path[1].p_bh) ---> brelse a buffer twice Finally got the following WARRNING when removing the buffer from lru: ============================================ VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Call Trace: <TASK> __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================ Fixes: ecb94f5fdf4b ("ext4: collapse a single extent tree block into the inode if possible") Cc: stable(a)kernel.org Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Tested-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Link: https://patch.msgid.link/20240822023545.1994557-9-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index d191aa400c35..4db1d47ccf0b 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1878,6 +1878,7 @@ static void ext4_ext_try_to_merge_up(handle_t *handle, path[0].p_hdr->eh_max = cpu_to_le16(max_root); brelse(path[1].p_bh); + path[1].p_bh = NULL; ext4_free_blocks(handle, inode, NULL, blk, 1, EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); } -- 2.46.1

2 1

[PATCH OLK-6.6] ext4: fix double brelse() the buffer of the extents path
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v6.6.55 commit 68a69cf60660c73990c1875f94a5551600b04775 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYR8Z CVE: CVE-2024-49882 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit dcaa6c31134c0f515600111c38ed7750003e1b9c upstream. In ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been released, otherwise it may be released twice. An example of what triggers this is as follows: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path->p_depth == 0 ext4_split_extent // 1. do split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&neh->eh_depth, 1) | ext4_find_extent | // return -ENOMEM |// get error and try zeroout |path = ext4_find_extent | path->p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path->p_depth = 0 | brelse(path[1].p_bh) ---> not set to NULL here |// zeroout success // 2. update path ext4_find_extent // 3. do split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&neh->eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path->p_depth = 1 read_extent_tree_block ---> return err // path[1].p_bh is still the old value ext4_free_ext_path ext4_ext_drop_refs // path->p_depth == 1 brelse(path[1].p_bh) ---> brelse a buffer twice Finally got the following WARRNING when removing the buffer from lru: ============================================ VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Call Trace: <TASK> __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================ Fixes: ecb94f5fdf4b ("ext4: collapse a single extent tree block into the inode if possible") Cc: stable(a)kernel.org Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Tested-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Link: https://patch.msgid.link/20240822023545.1994557-9-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 922718422ba6..25e077682aff 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1888,6 +1888,7 @@ static void ext4_ext_try_to_merge_up(handle_t *handle, path[0].p_hdr->eh_max = cpu_to_le16(max_root); brelse(path[1].p_bh); + path[1].p_bh = NULL; ext4_free_blocks(handle, inode, NULL, blk, 1, EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); } -- 2.46.1

2 1

[PATCH openEuler-1.0-LTS] ext4: fix double brelse() the buffer of the extents path
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v5.10.227 commit b6c29c8f3d7cb67b505f3b2f6c242d52298d1f2e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYR8Z CVE: CVE-2024-49882 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit dcaa6c31134c0f515600111c38ed7750003e1b9c upstream. In ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been released, otherwise it may be released twice. An example of what triggers this is as follows: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path->p_depth == 0 ext4_split_extent // 1. do split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&neh->eh_depth, 1) | ext4_find_extent | // return -ENOMEM |// get error and try zeroout |path = ext4_find_extent | path->p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path->p_depth = 0 | brelse(path[1].p_bh) ---> not set to NULL here |// zeroout success // 2. update path ext4_find_extent // 3. do split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&neh->eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path->p_depth = 1 read_extent_tree_block ---> return err // path[1].p_bh is still the old value ext4_free_ext_path ext4_ext_drop_refs // path->p_depth == 1 brelse(path[1].p_bh) ---> brelse a buffer twice Finally got the following WARRNING when removing the buffer from lru: ============================================ VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Call Trace: <TASK> __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================ Fixes: ecb94f5fdf4b ("ext4: collapse a single extent tree block into the inode if possible") Cc: stable(a)kernel.org Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Tested-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Link: https://patch.msgid.link/20240822023545.1994557-9-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 257e0b2b0e64..7d506187cc79 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1925,6 +1925,7 @@ static void ext4_ext_try_to_merge_up(handle_t *handle, path[0].p_hdr->eh_max = cpu_to_le16(max_root); brelse(path[1].p_bh); + path[1].p_bh = NULL; ext4_free_blocks(handle, inode, NULL, blk, 1, EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); } -- 2.46.1

2 1

[PATCH openEuler-22.03-LTS-SP1] ext4: aovid use-after-free in ext4_ext_insert_extent()
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v5.10.227 commit 5e811066c5ab709b070659197dccfb80ab650ddd category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYRCP CVE: CVE-2024-49883 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit a164f3a432aae62ca23d03e6d926b122ee5b860d upstream. As Ojaswin mentioned in Link, in ext4_ext_insert_extent(), if the path is reallocated in ext4_ext_create_new_leaf(), we'll use the stale path and cause UAF. Below is a sample trace with dummy values: ext4_ext_insert_extent path = *ppath = 2000 ext4_ext_create_new_leaf(ppath) ext4_find_extent(ppath) path = *ppath = 2000 if (depth > path[0].p_maxdepth) kfree(path = 2000); *ppath = path = NULL; path = kcalloc() = 3000 *ppath = 3000; return path; /* here path is still 2000, UAF! */ eh = path[depth].p_hdr ================================================================== BUG: KASAN: slab-use-after-free in ext4_ext_insert_extent+0x26d4/0x3330 Read of size 8 at addr ffff8881027bf7d0 by task kworker/u36:1/179 CPU: 3 UID: 0 PID: 179 Comm: kworker/u6:1 Not tainted 6.11.0-rc2-dirty #866 Call Trace: <TASK> ext4_ext_insert_extent+0x26d4/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 [...] Allocated by task 179: ext4_find_extent+0x81c/0x1f70 ext4_ext_map_blocks+0x146/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] Freed by task 179: kfree+0xcb/0x240 ext4_find_extent+0x7c0/0x1f70 ext4_ext_insert_extent+0xa26/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] ================================================================== So use *ppath to update the path to avoid the above problem. Reported-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Closes: https://lore.kernel.org/r/ZqyL6rmtwl6N4MWR@li-bb2b2a4c-3307-11b2-a85c-8fa5c… Fixes: 10809df84a4d ("ext4: teach ext4_ext_find_extent() to realloc path if necessary") Cc: stable(a)kernel.org Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Link: https://patch.msgid.link/20240822023545.1994557-7-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index af7b253dfe86..04b0346599c5 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2106,6 +2106,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, ppath, newext); if (err) goto cleanup; + path = *ppath; depth = ext_depth(inode); eh = path[depth].p_hdr; -- 2.46.1

2 1

[PATCH OLK-5.10] ext4: aovid use-after-free in ext4_ext_insert_extent()
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v5.10.227 commit 5e811066c5ab709b070659197dccfb80ab650ddd category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYRCP CVE: CVE-2024-49883 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit a164f3a432aae62ca23d03e6d926b122ee5b860d upstream. As Ojaswin mentioned in Link, in ext4_ext_insert_extent(), if the path is reallocated in ext4_ext_create_new_leaf(), we'll use the stale path and cause UAF. Below is a sample trace with dummy values: ext4_ext_insert_extent path = *ppath = 2000 ext4_ext_create_new_leaf(ppath) ext4_find_extent(ppath) path = *ppath = 2000 if (depth > path[0].p_maxdepth) kfree(path = 2000); *ppath = path = NULL; path = kcalloc() = 3000 *ppath = 3000; return path; /* here path is still 2000, UAF! */ eh = path[depth].p_hdr ================================================================== BUG: KASAN: slab-use-after-free in ext4_ext_insert_extent+0x26d4/0x3330 Read of size 8 at addr ffff8881027bf7d0 by task kworker/u36:1/179 CPU: 3 UID: 0 PID: 179 Comm: kworker/u6:1 Not tainted 6.11.0-rc2-dirty #866 Call Trace: <TASK> ext4_ext_insert_extent+0x26d4/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 [...] Allocated by task 179: ext4_find_extent+0x81c/0x1f70 ext4_ext_map_blocks+0x146/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] Freed by task 179: kfree+0xcb/0x240 ext4_find_extent+0x7c0/0x1f70 ext4_ext_insert_extent+0xa26/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] ================================================================== So use *ppath to update the path to avoid the above problem. Reported-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Closes: https://lore.kernel.org/r/ZqyL6rmtwl6N4MWR@li-bb2b2a4c-3307-11b2-a85c-8fa5c… Fixes: 10809df84a4d ("ext4: teach ext4_ext_find_extent() to realloc path if necessary") Cc: stable(a)kernel.org Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Link: https://patch.msgid.link/20240822023545.1994557-7-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 1c70f48238b0..d191aa400c35 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2106,6 +2106,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, ppath, newext); if (err) goto cleanup; + path = *ppath; depth = ext_depth(inode); eh = path[depth].p_hdr; -- 2.46.1

2 1

[PATCH OLK-6.6] ext4: aovid use-after-free in ext4_ext_insert_extent()
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v6.6.55 commit 8162ee5d94b8c0351be0a9321be134872a7654a1 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYRCP CVE: CVE-2024-49883 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit a164f3a432aae62ca23d03e6d926b122ee5b860d upstream. As Ojaswin mentioned in Link, in ext4_ext_insert_extent(), if the path is reallocated in ext4_ext_create_new_leaf(), we'll use the stale path and cause UAF. Below is a sample trace with dummy values: ext4_ext_insert_extent path = *ppath = 2000 ext4_ext_create_new_leaf(ppath) ext4_find_extent(ppath) path = *ppath = 2000 if (depth > path[0].p_maxdepth) kfree(path = 2000); *ppath = path = NULL; path = kcalloc() = 3000 *ppath = 3000; return path; /* here path is still 2000, UAF! */ eh = path[depth].p_hdr ================================================================== BUG: KASAN: slab-use-after-free in ext4_ext_insert_extent+0x26d4/0x3330 Read of size 8 at addr ffff8881027bf7d0 by task kworker/u36:1/179 CPU: 3 UID: 0 PID: 179 Comm: kworker/u6:1 Not tainted 6.11.0-rc2-dirty #866 Call Trace: <TASK> ext4_ext_insert_extent+0x26d4/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 [...] Allocated by task 179: ext4_find_extent+0x81c/0x1f70 ext4_ext_map_blocks+0x146/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] Freed by task 179: kfree+0xcb/0x240 ext4_find_extent+0x7c0/0x1f70 ext4_ext_insert_extent+0xa26/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] ================================================================== So use *ppath to update the path to avoid the above problem. Reported-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Closes: https://lore.kernel.org/r/ZqyL6rmtwl6N4MWR@li-bb2b2a4c-3307-11b2-a85c-8fa5c… Fixes: 10809df84a4d ("ext4: teach ext4_ext_find_extent() to realloc path if necessary") Cc: stable(a)kernel.org Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Link: https://patch.msgid.link/20240822023545.1994557-7-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 25e077682aff..ef37cee9c27e 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2115,6 +2115,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, ppath, newext); if (err) goto cleanup; + path = *ppath; depth = ext_depth(inode); eh = path[depth].p_hdr; -- 2.46.1

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[PATCH openEuler-1.0-LTS] ext4: aovid use-after-free in ext4_ext_insert_extent()
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v5.10.227 commit 5e811066c5ab709b070659197dccfb80ab650ddd category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYRCP CVE: CVE-2024-49883 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit a164f3a432aae62ca23d03e6d926b122ee5b860d upstream. As Ojaswin mentioned in Link, in ext4_ext_insert_extent(), if the path is reallocated in ext4_ext_create_new_leaf(), we'll use the stale path and cause UAF. Below is a sample trace with dummy values: ext4_ext_insert_extent path = *ppath = 2000 ext4_ext_create_new_leaf(ppath) ext4_find_extent(ppath) path = *ppath = 2000 if (depth > path[0].p_maxdepth) kfree(path = 2000); *ppath = path = NULL; path = kcalloc() = 3000 *ppath = 3000; return path; /* here path is still 2000, UAF! */ eh = path[depth].p_hdr ================================================================== BUG: KASAN: slab-use-after-free in ext4_ext_insert_extent+0x26d4/0x3330 Read of size 8 at addr ffff8881027bf7d0 by task kworker/u36:1/179 CPU: 3 UID: 0 PID: 179 Comm: kworker/u6:1 Not tainted 6.11.0-rc2-dirty #866 Call Trace: <TASK> ext4_ext_insert_extent+0x26d4/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 [...] Allocated by task 179: ext4_find_extent+0x81c/0x1f70 ext4_ext_map_blocks+0x146/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] Freed by task 179: kfree+0xcb/0x240 ext4_find_extent+0x7c0/0x1f70 ext4_ext_insert_extent+0xa26/0x3330 ext4_ext_map_blocks+0xe22/0x2d40 ext4_map_blocks+0x71e/0x1700 ext4_do_writepages+0x1290/0x2800 ext4_writepages+0x26d/0x4e0 do_writepages+0x175/0x700 [...] ================================================================== So use *ppath to update the path to avoid the above problem. Reported-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Closes: https://lore.kernel.org/r/ZqyL6rmtwl6N4MWR@li-bb2b2a4c-3307-11b2-a85c-8fa5c… Fixes: 10809df84a4d ("ext4: teach ext4_ext_find_extent() to realloc path if necessary") Cc: stable(a)kernel.org Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Link: https://patch.msgid.link/20240822023545.1994557-7-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index e29b55991e8f..257e0b2b0e64 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2152,6 +2152,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, ppath, newext); if (err) goto cleanup; + path = *ppath; depth = ext_depth(inode); eh = path[depth].p_hdr; -- 2.46.1

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[PATCH openEuler-22.03-LTS-SP1] ext4: avoid use-after-free in ext4_ext_show_leaf()
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v5.10.227 commit b0cb4561fc4284d04e69c8a66c8504928ab2484e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYR98 CVE: CVE-2024-49889 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 4e2524ba2ca5f54bdbb9e5153bea00421ef653f5 ] In ext4_find_extent(), path may be freed by error or be reallocated, so using a previously saved *ppath may have been freed and thus may trigger use-after-free, as follows: ext4_split_extent path = *ppath; ext4_split_extent_at(ppath) path = ext4_find_extent(ppath) ext4_split_extent_at(ppath) // ext4_find_extent fails to free path // but zeroout succeeds ext4_ext_show_leaf(inode, path) eh = path[depth].p_hdr // path use-after-free !!! Similar to ext4_split_extent_at(), we use *ppath directly as an input to ext4_ext_show_leaf(). Fix a spelling error by the way. Same problem in ext4_ext_handle_unwritten_extents(). Since 'path' is only used in ext4_ext_show_leaf(), remove 'path' and use *ppath directly. This issue is triggered only when EXT_DEBUG is defined and therefore does not affect functionality. Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Tested-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Link: https://patch.msgid.link/20240822023545.1994557-5-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index db3ed0fb7bdb..af7b253dfe86 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3341,7 +3341,7 @@ static int ext4_split_extent_at(handle_t *handle, } /* - * ext4_split_extents() splits an extent and mark extent which is covered + * ext4_split_extent() splits an extent and mark extent which is covered * by @map as split_flags indicates * * It may result in splitting the extent into multiple extents (up to three) @@ -3418,7 +3418,7 @@ static int ext4_split_extent(handle_t *handle, goto out; } - ext4_ext_show_leaf(inode, path); + ext4_ext_show_leaf(inode, *ppath); out: return err ? err : allocated; } @@ -3883,14 +3883,13 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode, struct ext4_ext_path **ppath, int flags, unsigned int allocated, ext4_fsblk_t newblock) { - struct ext4_ext_path __maybe_unused *path = *ppath; int ret = 0; int err = 0; ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n", (unsigned long long)map->m_lblk, map->m_len, flags, allocated); - ext4_ext_show_leaf(inode, path); + ext4_ext_show_leaf(inode, *ppath); /* * When writing into unwritten space, we should not fail to @@ -3987,7 +3986,7 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode, if (allocated > map->m_len) allocated = map->m_len; map->m_len = allocated; - ext4_ext_show_leaf(inode, path); + ext4_ext_show_leaf(inode, *ppath); out2: return err ? err : allocated; } -- 2.46.1

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[PATCH OLK-5.10] ext4: avoid use-after-free in ext4_ext_show_leaf()
by Baokun Li 02 Nov '24

02 Nov '24

stable inclusion from stable-v5.10.227 commit b0cb4561fc4284d04e69c8a66c8504928ab2484e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYR98 CVE: CVE-2024-49889 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- [ Upstream commit 4e2524ba2ca5f54bdbb9e5153bea00421ef653f5 ] In ext4_find_extent(), path may be freed by error or be reallocated, so using a previously saved *ppath may have been freed and thus may trigger use-after-free, as follows: ext4_split_extent path = *ppath; ext4_split_extent_at(ppath) path = ext4_find_extent(ppath) ext4_split_extent_at(ppath) // ext4_find_extent fails to free path // but zeroout succeeds ext4_ext_show_leaf(inode, path) eh = path[depth].p_hdr // path use-after-free !!! Similar to ext4_split_extent_at(), we use *ppath directly as an input to ext4_ext_show_leaf(). Fix a spelling error by the way. Same problem in ext4_ext_handle_unwritten_extents(). Since 'path' is only used in ext4_ext_show_leaf(), remove 'path' and use *ppath directly. This issue is triggered only when EXT_DEBUG is defined and therefore does not affect functionality. Signed-off-by: Baokun Li <libaokun1(a)huawei.com> Reviewed-by: Jan Kara <jack(a)suse.cz> Reviewed-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Tested-by: Ojaswin Mujoo <ojaswin(a)linux.ibm.com> Link: https://patch.msgid.link/20240822023545.1994557-5-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso(a)mit.edu> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Baokun Li <libaokun1(a)huawei.com> --- fs/ext4/extents.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 32746616faf7..1c70f48238b0 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3318,7 +3318,7 @@ static int ext4_split_extent_at(handle_t *handle, } /* - * ext4_split_extents() splits an extent and mark extent which is covered + * ext4_split_extent() splits an extent and mark extent which is covered * by @map as split_flags indicates * * It may result in splitting the extent into multiple extents (up to three) @@ -3395,7 +3395,7 @@ static int ext4_split_extent(handle_t *handle, goto out; } - ext4_ext_show_leaf(inode, path); + ext4_ext_show_leaf(inode, *ppath); out: return err ? err : allocated; } @@ -3860,14 +3860,13 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode, struct ext4_ext_path **ppath, int flags, unsigned int allocated, ext4_fsblk_t newblock) { - struct ext4_ext_path __maybe_unused *path = *ppath; int ret = 0; int err = 0; ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n", (unsigned long long)map->m_lblk, map->m_len, flags, allocated); - ext4_ext_show_leaf(inode, path); + ext4_ext_show_leaf(inode, *ppath); /* * When writing into unwritten space, we should not fail to @@ -3964,7 +3963,7 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode, if (allocated > map->m_len) allocated = map->m_len; map->m_len = allocated; - ext4_ext_show_leaf(inode, path); + ext4_ext_show_leaf(inode, *ppath); out2: return err ? err : allocated; } -- 2.46.1

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