CVE-2024-35921

In the Linux kernel, the following vulnerability has been resolved:

media: mediatek: vcodec: Fix oops when HEVC init fails

The stateless HEVC decoder saves the instance pointer in the context regardless if the initialization worked or not. This caused a use after free, when the pointer is freed in case of a failure in the deinit function. Only store the instance pointer when the initialization was successful, to solve this issue.

Hardware name: Acer Tomato (rev3 - 4) board (DT) pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : vcodecvpusendmsg+0x4c/0x190 [mtkvcodecdec] lr : vcodecsendapipi+0x78/0x170 [mtkvcodecdec] sp : ffff80008750bc20 x29: ffff80008750bc20 x28: ffff1299f6d70000 x27: 0000000000000000 x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 x23: ffff80008750bc98 x22: 000000000000a003 x21: ffffd45c4cfae000 x20: 0000000000000010 x19: ffff1299fd668310 x18: 000000000000001a x17: 000000040044ffff x16: ffffd45cb15dc648 x15: 0000000000000000 x14: ffff1299c08da1c0 x13: ffffd45cb1f87a10 x12: ffffd45cb2f5fe80 x11: 0000000000000001 x10: 0000000000001b30 x9 : ffffd45c4d12b488 x8 : 1fffe25339380d81 x7 : 0000000000000001 x6 : ffff1299c9c06c00 x5 : 0000000000000132 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000010 x1 : ffff80008750bc98 x0 : 0000000000000000 Call trace: vcodecvpusendmsg+0x4c/0x190 [mtkvcodecdec] vcodecsendapipi+0x78/0x170 [mtkvcodecdec] vpudecdeinit+0x1c/0x30 [mtkvcodecdec] vdechevcslicedeinit+0x30/0x98 [mtkvcodecdec] vdecifdeinit+0x38/0x68 [mtkvcodecdec] mtkvcodecdecrelease+0x20/0x40 [mtkvcodecdec] fopsvcodecrelease+0x64/0x118 [mtkvcodecdec] v4l2release+0x7c/0x100 _fput+0x80/0x2d8 _fputsync+0x58/0x70 _arm64sysclose+0x40/0x90 invokesyscall+0x50/0x128 el0svccommon.constprop.0+0x48/0xf0 doel0svc+0x24/0x38 el0svc+0x38/0xd8 el0t64synchandler+0xc0/0xc8 el0t64sync+0x1a8/0x1b0 Code: d503201f f9401660 b900127f b900227f (f9400400)