DEBIAN-CVE-2021-47162
- Source
- https://security-tracker.debian.org/tracker/DEBIAN-CVE-2021-47162
- Import Source
- https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47162.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/DEBIAN-CVE-2021-47162
- Upstream
- Published
- 2024-03-25T10:15:08Z
- Modified
- 2025-09-19T06:21:18Z
- Summary
- [none]
- Details
-
In the Linux kernel, the following vulnerability has been resolved: tipc: skblinearize the head skb when reassembling msgs It's not a good idea to append the frag skb to a skb's fraglist if the fraglist already has skbs from elsewhere, such as this skb was created by pskbcopy() where the fraglist was cloned (all the skbs in it were skbget'ed) and shared by multiple skbs. However, the new appended frag skb should have been only seen by the current skb. Otherwise, it will cause use after free crashes as this appended frag skb are seen by multiple skbs but it only got skbget called once. The same thing happens with a skb updated by pskbmaypull() with a skbcloned skb. Li Shuang has reported quite a few crashes caused by this when doing testing over macvlan devices: [] kernel BUG at net/core/skbuff.c:1970! [] Call Trace: [] skbclone+0x4d/0xb0 [] macvlanbroadcast+0xd8/0x160 [macvlan] [] macvlanprocessbroadcast+0x148/0x150 [macvlan] [] processonework+0x1a7/0x360 [] workerthread+0x30/0x390 [] kernel BUG at mm/usercopy.c:102! [] Call Trace: [] checkheapobject+0xd3/0x100 [] _checkobjectsize+0xff/0x16b [] simplecopytoiter+0x1c/0x30 [] _skbdatagramiter+0x7d/0x310 [] _skbdatagramiter+0x2a5/0x310 [] skbcopydatagramiter+0x3b/0x90 [] tipcrecvmsg+0x14a/0x3a0 [tipc] [] _sysrecvmsg+0x91/0x150 [] _sysrecvmsg+0x7b/0xc0 [] kernel BUG at mm/slub.c:305! [] Call Trace: [] <IRQ> [] kmemcachefree+0x3ff/0x400 [] _netifreceiveskbcore+0x12c/0xc40 [] ? kmemcachealloc+0x12e/0x270 [] netifreceiveskbinternal+0x3d/0xb0 [] ? getrxpageinfo+0x8e/0xa0 [be2net] [] bepoll+0x6ef/0xd00 [be2net] [] ? irqexit+0x4f/0x100 [] netrxaction+0x149/0x3b0 ... This patch is to fix it by linearizing the head skb if it has fraglist set in tipcbufappend(). Note that we choose to do this before calling skbunshare(), as _skblinearize() will avoid skbcopy(). Also, we can not just drop the fraglist either as the early time.
- References
Affected packages
Debian:11 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source
Debian:12 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source
Debian:13 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source
Debian:14 / linux
Package
- Name
- linux
- Purl
- pkg:deb/debian/linux?arch=source