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once in a lifetime pull request; Hurr durr I'ma ninja sloth #866

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wants to merge 1 commit into from
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once in a lifetime pull request; Hurr durr I'ma ninja sloth #866

wants to merge 1 commit into from

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pparaxan
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for_the_culture

@WilliamAnimate
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LGTM; should merge at 6.9.4

@pparaxan
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Context: the kernel is now on 6.9

@tigercoding56
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i support this +1

@pparaxan pparaxan changed the title once in a lifetime pull request once in a lifetime pull request; Hurr durr I'ma ninja sloth May 18, 2024
@pparaxan pparaxan closed this by deleting the head repository Jun 5, 2024
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Aug 22, 2024
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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Sep 4, 2024
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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Sep 4, 2024
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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Oct 8, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Oct 8, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Oct 8, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Oct 8, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Oct 8, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Oct 8, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
KexyBiscuit pushed a commit to AOSC-Tracking/linux that referenced this pull request Oct 8, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
intersectRaven pushed a commit to intersectRaven/linux that referenced this pull request Oct 10, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
riccardv pushed a commit to riccardv/linux that referenced this pull request Oct 10, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
1054009064 pushed a commit to 1054009064/linux that referenced this pull request Oct 10, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Oct 14, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Oct 15, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
staging-kernelci-org pushed a commit to kernelci/linux that referenced this pull request Oct 17, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
1054009064 pushed a commit to 1054009064/linux that referenced this pull request Oct 17, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
1054009064 pushed a commit to 1054009064/linux that referenced this pull request Oct 17, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
1054009064 pushed a commit to 1054009064/linux that referenced this pull request Nov 8, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
1054009064 pushed a commit to 1054009064/linux that referenced this pull request Nov 8, 2024
commit a164f3a 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 torvalds#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 <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 10809df ("ext4: teach ext4_ext_find_extent() to realloc path if necessary")
Cc: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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3 participants