CVE - CVE-2024-49884

CVE-ID
CVE-2024-49884	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
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: <TASK> 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.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/5d949ea75bb529ea6342e83465938a3b0ac51238 URL:https://git.kernel.org/stable/c/5d949ea75bb529ea6342e83465938a3b0ac51238 MISC:https://git.kernel.org/stable/c/8fe117790b37c84c651e2bad9efc0e7fda73c0e3 URL:https://git.kernel.org/stable/c/8fe117790b37c84c651e2bad9efc0e7fda73c0e3 MISC:https://git.kernel.org/stable/c/915ac3630488af0ca194dc63b86d99802b4f6e18 URL:https://git.kernel.org/stable/c/915ac3630488af0ca194dc63b86d99802b4f6e18 MISC:https://git.kernel.org/stable/c/a5401d4c3e2a3d25643c567d26e6de327774a2c9 URL:https://git.kernel.org/stable/c/a5401d4c3e2a3d25643c567d26e6de327774a2c9 MISC:https://git.kernel.org/stable/c/c26ab35702f8cd0cdc78f96aa5856bfb77be798f URL:https://git.kernel.org/stable/c/c26ab35702f8cd0cdc78f96aa5856bfb77be798f MISC:https://git.kernel.org/stable/c/cafcc1bd62934547c76abf46c6d0d54f135006fe URL:https://git.kernel.org/stable/c/cafcc1bd62934547c76abf46c6d0d54f135006fe MISC:https://git.kernel.org/stable/c/e52f933598b781d291b9297e39c463536da0e185 URL:https://git.kernel.org/stable/c/e52f933598b781d291b9297e39c463536da0e185
Assigning CNA
kernel.org
Date Record Created
20241021	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20241021)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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