Description
In the Linux kernel, the following vulnerability has been resolved: ext4: Fix function prototype mismatch for ext4_feat_ktype With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. ext4_feat_ktype was setting the "release" handler to "kfree", which doesn't have a matching function prototype. Add a simple wrapper with the correct prototype. This was found as a result of Clang's new -Wcast-function-type-strict flag, which is more sensitive than the simpler -Wcast-function-type, which only checks for type width mismatches. Note that this code is only reached when ext4 is a loadable module and it is being unloaded: CFI failure at kobject_put+0xbb/0x1b0 (target: kfree+0x0/0x180; expected type: 0x7c4aa698) ... RIP: 0010:kobject_put+0xbb/0x1b0 ... Call Trace: <TASK> ext4_exit_sysfs+0x14/0x60 [ext4] cleanup_module+0x67/0xedb [ext4]
Product status
b99fee58a20ab8e0557cce87b6f187e325993142 (git) before 2b69cdd9f9a7f596e3dd31f05f9852940d177924
b99fee58a20ab8e0557cce87b6f187e325993142 (git) before 99e3fd21f8fc975c95e8cf76fbf6a3d2656f8f71
b99fee58a20ab8e0557cce87b6f187e325993142 (git) before 1ba10d3640e9783dad811fe4e24d55465c37c64d
b99fee58a20ab8e0557cce87b6f187e325993142 (git) before c98077f7598a562f51051eec043be0cb3e1b1b5e
b99fee58a20ab8e0557cce87b6f187e325993142 (git) before 0a1394e07c5d6bf1bfc25db8589ff1b1bfb6f46a
b99fee58a20ab8e0557cce87b6f187e325993142 (git) before 94d8de83286fb1827340eba35b61c308f6b46ead
b99fee58a20ab8e0557cce87b6f187e325993142 (git) before 118901ad1f25d2334255b3d50512fa20591531cd
4.16
Any version before 4.16
4.19.274 (semver)
5.4.233 (semver)
5.10.170 (semver)
5.15.96 (semver)
6.1.14 (semver)
6.2.1 (semver)
6.3 (original_commit_for_fix)
References
git.kernel.org/...c/2b69cdd9f9a7f596e3dd31f05f9852940d177924
git.kernel.org/...c/99e3fd21f8fc975c95e8cf76fbf6a3d2656f8f71
git.kernel.org/...c/1ba10d3640e9783dad811fe4e24d55465c37c64d
git.kernel.org/...c/c98077f7598a562f51051eec043be0cb3e1b1b5e
git.kernel.org/...c/0a1394e07c5d6bf1bfc25db8589ff1b1bfb6f46a
git.kernel.org/...c/94d8de83286fb1827340eba35b61c308f6b46ead
git.kernel.org/...c/118901ad1f25d2334255b3d50512fa20591531cd
