cbcvebase.
CVE-2024-49884
published 2024-10-21

CVE-2024-49884: In the Linux kernel, the following vulnerability has been resolved: ext4: fix slab-use-after-free in ext4_split_extent_at() We hit the following…

PriorityP339high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.27%
18.8th percentile
In the Linux kernel, the following vulnerability has been resolved: ext4: fix slab-use-after-free in ext4_split_extent_at() We hit the following use-after-free: BUG: KASAN: slab-use-after-free in ext4_split_extent_at+0xba8/0xcc0 Read of size 2 at addr ffff88810548ed08 by task kworker/u20:0/40 CPU: 0 PID: 40 Comm: kworker/u20:0 Not tainted 6.9.0-dirty #724 Call Trace: kasan_report+0x93/0xc0 ext4_split_extent_at+0xba8/0xcc0 ext4_split_extent.isra.0+0x18f/0x500 ext4_split_convert_extents+0x275/0x750 ext4_ext_handle_unwritten_extents+0x73e/0x1580 ext4_ext_map_blocks+0xe20/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] Allocated by task 40: __kmalloc_noprof+0x1ac/0x480 ext4_find_extent+0xf3b/0x1e70 ext4_ext_map_blocks+0x188/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] Freed by task 40: kfree+0xf1/0x2b0 ext4_find_extent+0xa71/0x1e70 ext4_ext_insert_extent+0xa22/0x3260 ext4_split_extent_at+0x3ef/0xcc0 ext4_split_extent.isra.0+0x18f/0x500 ext4_split_convert_extents+0x275/0x750 ext4_ext_handle_unwritten_extents+0x73e/0x1580 ext4_ext_map_blocks+0xe20/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] The flow of issue triggering is as follows: ext4_split_extent_at path = *ppath ext4_ext_insert_extent(ppath) ext4_ext_create_new_leaf(ppath) ext4_find_extent(orig_path) path = *orig_path read_extent_tree_block // return -ENOMEM or -EIO ext4_free_ext_path(path) kfree(path) *orig_path = NULL a. If err is -ENOMEM: ext4_ext_dirty(path + path->p_depth) // path use-after-free !!! b. If err is -EIO and we have EXT_DEBUG defined: ext4_ext_show_leaf(path) eh = path[depth].p_hdr // path also use-after-free !!! So when trying to zeroout or fix the extent length, call ext4_find_extent() to update the path. In addition we use *ppath directly as an ext4_ext_show_leaf() input to avoid possible use-after-free when EXT_DEBUG is defined, and to avoid unnecessary path updates.

Affected

37 ranges· showing 25
VendorProductVersion rangeFixed in
debiandebian_linux
debianlinux< linux 6.1.115-1 (bookworm)linux 6.1.115-1 (bookworm)
debianlinux-6.1< linux 6.1.115-1 (bookworm)linux 6.1.115-1 (bookworm)
linuxlinux
linuxlinux>= dfe5080939ea4686b3414b5d970a9b26733c57a4 < 393a46f60ea4f249dc9d496d4eb2d542f5e11ade393a46f60ea4f249dc9d496d4eb2d542f5e11ade
linuxlinux>= dfe5080939ea4686b3414b5d970a9b26733c57a4 < 448100a29395b0c8b4c42967155849fe0fbe808f448100a29395b0c8b4c42967155849fe0fbe808f
linuxlinux>= dfe5080939ea4686b3414b5d970a9b26733c57a4 < e52f933598b781d291b9297e39c463536da0e185e52f933598b781d291b9297e39c463536da0e185
linuxlinux>= dfe5080939ea4686b3414b5d970a9b26733c57a4 < cafcc1bd62934547c76abf46c6d0d54f135006fecafcc1bd62934547c76abf46c6d0d54f135006fe
linuxlinux>= dfe5080939ea4686b3414b5d970a9b26733c57a4 < a5401d4c3e2a3d25643c567d26e6de327774a2c9a5401d4c3e2a3d25643c567d26e6de327774a2c9
linuxlinux>= dfe5080939ea4686b3414b5d970a9b26733c57a4 < 8fe117790b37c84c651e2bad9efc0e7fda73c0e38fe117790b37c84c651e2bad9efc0e7fda73c0e3
linuxlinux>= dfe5080939ea4686b3414b5d970a9b26733c57a4 < 5d949ea75bb529ea6342e83465938a3b0ac512385d949ea75bb529ea6342e83465938a3b0ac51238
linuxlinux>= dfe5080939ea4686b3414b5d970a9b26733c57a4 < 915ac3630488af0ca194dc63b86d99802b4f6e18915ac3630488af0ca194dc63b86d99802b4f6e18
linuxlinux>= dfe5080939ea4686b3414b5d970a9b26733c57a4 < c26ab35702f8cd0cdc78f96aa5856bfb77be798fc26ab35702f8cd0cdc78f96aa5856bfb77be798f
linuxlinux_kernel>= 0 < 5.10.234-15.10.234-1
linuxlinux_kernel>= 0 < 6.1.115-16.1.115-1
linuxlinux_kernel>= 0 < 6.11.4-16.11.4-1
linuxlinux_kernel>= 0 < 6.11.4-16.11.4-1
linuxlinux_kernel>= 0 < 5.4.0-211.2315.4.0-211.231
linuxlinux_kernel>= 0 < 5.15.0-127.1375.15.0-127.137
linuxlinux_kernel>= 0 < 6.8.0-54.566.8.0-54.56
linuxlinux_kernel>= 0 < 6.11.0-18.186.11.0-18.18
linuxlinux_kernel>= 3.18 < 4.19.3234.19.323
linuxlinux_kernel>= 4.20 < 5.4.2905.4.290
linuxlinux_kernel>= 5.11 < 5.15.1685.15.168
linuxlinux_kernel>= 5.16 < 6.1.1136.1.113

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian7.8HIGH
vendor_msrc7.8HIGH
vendor_redhat7.8HIGH
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